Spring Build

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10/16/13 springbuild

www.chopperhandbook.com/springbuild.htm 1/47

The Rude and Crude Old School Springer Build

I still think that our original CBH Springer is about one of the finest designs on the market today but even though it is simple to build westill get requests for a design that is even less complex and less expensive to fabricate.

In response to this demand weve prepared this modern revision of a true Old School Springer very similar to those we used to build inthe sixties. The fancier CBH Springer we published in 2005 was actually just a refinement of this old original design.

We call this one the Rude and Crude Old School Springer because thats exactly what it is; pretty rude and pretty crude but it rides andhandles very well and you dont need to do any fancy machine work or have any special tools. All of the components are readi ly available,

nothing is custom made, and it is a relatively economical fork system to build if you want an affordable Springer on your bike.

Springers have been used on bikes for decades, in fact the first were introduced way back in the 1800s on bicycles and Harley was anearly adopter for their motorcycle applications but they didnt become the cool thing to do on chopped bikes until custom buildersexceeded the limits for modern hydraulic forks in the early sixties.

Once you start to rake the neck angle on a bike and then combine it with extended forks the effectiveness of the so-called modernhydraulic forks soon start to fail and fail very fast. It didnt take to long for bike builders to realize that running hydraulic forks on any bikehaving a rake angle of more than 35 degrees was asking for trouble so the fall-back at first was just some solid legs with no suspensionsystem at all except for the springy bend in the legs themselves. These long raked solid forks behaved almost exactly like a set of non-performing hydraulic forks only better. The drawback was that over time they began to take a set and looked like theyd been run througha ring roller. To counteract this tendency we started to add a girder truss to the backside of these rigid legs and it worked up to a pointwhere you still had a little springiness but beyond this point you simply ended up with a very rigid, non-yielding set of forks with nosuspension component at all since they didnt flex even a few fractions of an inch.

(For those of you who still remember the old rigid forks you might be interested to know that Freddie Hernandez still builds them but hebuilds them a lot better than they used to be so give him a call if you want something unique).

The solution for raked bikes ended up being a resurrection of the old original Springer except with massively extended legs. This conceptworked and it worked no matter how long the forks were and believe me back in those days we were building some incredibly extendedforks for bikes with outlandish amounts of rake. The old Springer suspension kept working no matter how far we pushed the designenvelope. Even today on a radical bike the old extended Springer design concept will provide a good suspension solution to a trickydesign problem. An excellent example of this old technology that has been optimized can be seen in the work of Springer builderextraordinaire, Sugar Bear (Al Myers), seen below.

Figure 1

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,back in the early days of the craft.

There are several other noted Springer builders out there today. Mondo at Denvers Choppers comes to mind as well as Jeri Exner, BigAl Wilkerson and one of the pioneers of the craft, Freddie Hernandez, but this article isnt about where to buy a good set of forks but howto build them.

Tools

About all you need to build these forks are a hacksaw or reciprocal saw, belt sander, small drill press, mini-grinder and access to a

welder. Depending on which rocker system you decide to use you might also have to buy a tap to thread the rockers. Of course moretools are great if you have them but for a guy just starting out these forks require a minimum of gear. For a complete rundown on tools andsome substitutions or workarounds see the Girder building article as it goes into considerable depth on the subject.

I get a little bent when I hear about people postponing a project because they dont have a complete computerized machine shop at theirdisposal since if we all waited for that day to arrive nothing would ever get done. I figure that if guys like Burt Munro can build a recordsetting bike with nothing but hand tools and a power drill then it seems to me like anybody with the desire can accomplish amazing featsof engineering and fabrication.

Materials and Costs

To build these forks you need relatively few raw materials and in fact most people who have been building their own frames probably

have a lot of the appropriate stock already at hand in their scrap pile. You can very easily do some creative scrounging at local fabricationshops and come up with the steel needed for the project just by digging through the box of drops most fab shops have in the corner ofthe shop. If push comes to shove you can buy on-line through suppliers such as Online Metals which Ive had excellent results with. In factI now use this resource as my main steel supply outlet as they usually beat the prices and delivery times from my local sources.

As of 6-14-08 the costs for all of the steel and tubing for this particular design ordered on-line, which is premium prices, is $146.93, whichincludes shipping. Local sourcing and scrounging can bring this down significantly. Unfortunately Springers compared to other types offorks are somewhat material intensive so it is pretty hard to save a bunch of money on the raw materials. The raw stock doesnt have tobe ordered all at one time so the cost can be spread out as youre working on specific parts of the design and if youre willing to do somescrounging you can save some very big bucks. I built my first Springer entirely from scrap and swap meet parts for fewer than thirty bucksbut then again that was almost forty years ago so you have to factor inflation into the picture.

My goal for this project was to keep the finished product ready to install at under three hundred and fi fty dollars minus powder coating.

The pre-made materials and parts such as the springs, retainers, bushings and spring rods can be purchased from a wide variety ofsources. I prefer to do business with only a few companies for these parts, the first being Bitter End Old School Choppers and thesecond being 45 Restoration Company. I dont get any kickbacks in case youre wondering. Both outfits offer below average prices andfar above average services and Ive tried doing business with a lot of suppliers. Both of these shops stand out against the rest and theystand behind what they sell which is very unusual today.

On average, including shipping, the cost for all the springs, rods, retainers, nuts, sleeves and other small parts ran $157.85 (chromed) soyou can see were already up to $334.78 paying full retail and buying everything on-line. To me this is expensive but compared to $800for a cheap imported piece of junk it looks pretty good. Compared to a top flight American made Springer at $2500 it looks really goodindeed.

Projects like this one arent always about saving money but more about gaining the pride and satisfaction of doing something yourselfthat makes your bike unique and a truly personal creation.

Materials Preparation

Im kind of a fanatic about material prep and the older I get the more obsessed I become.

The first thing I normally do when receiving an order of stock is to clean i t with lacquer thinner. On tubing I also swab out the interior bores,as they are usually full of filth.


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Figure 2

The snapshot above is the crap that came out of a relatively clean section of DOM tubing.

Once the tubing is clean Ill check it for straightness. Youd be surprised to find how many times you receive tubing that has a slight bow to

it. If you end up with some distorted sections you really cant use it for Springer legs. If youre lucky and have some nice straight stock thenyou need to examine every square inch of the exterior surfaces and look for any significant gouges, nicks, dents, cracks or otherimperfections.

Unfortunately steel products are treated like crap at most distribution yards so its rare that you receive some good virgin material. I haveto admit that Ive been getting some good stuff from the online sources. In some cases far better that what I can purchase locally but itdoes cost more.

On flat stock I try to remove as much mill scale as possible before I do any pattern layout. At least I give it a quick sanding and knock offany sharp edges where the material has been cut to order. Whatever you do dont try to use hot-rolled material for anything as it takes farto long to get down through the mill scale to find a good surface and even then its probably going to be marginal. Its tempting to buy it asits a lot cheaper but I dont think worth it in the long run. Every now and then however you have to use it to get the sizes you might requireso if that happens be prepared for a lot of prep work.

Design Considerations

From my standpoint I look at a typical Springer as being made up from four basic elements. There are the legs or fork tubes, both thefront and the rear. Then there is what I call the structural elements, which are the bridges, perches and trees (yokes). Then there are thesuspension elements, which are the springs, rods, rod bushing, spring seats and associated fasteners. Finally there are the rockersthemselves and their associated hardware and fasteners. I give the rockers a separate class of their own and treat them as distinctelements because there are several different rocker variations that can be used with any suspension system.

I typically design a Springer from the bottom up. I start with a rocker design and then work upward through the other various elements.During fabrication I use the same procedure, which is opposite to what many builders do. There is nothing special about my personalmethod. It is just how I was taught to do things so you can work from the top down if that better suits your particular fabrication habits.

Almost the worse thing you can do to a chopped bike is to install an off-the-shelf Springer as in almost 90% of the cases the pre-madeitem will not suit the design characteristics of your particular bike. Springers are a little peculiar and what works with one bike geometrywont work with another. Of course the factory spent years designing their own forks and rockers and they work wonderfully for the bikesthey were designed for. Bolting a stock fork to a little custom made Bobber with a 32 degree neck as opposed to the stock 28 and 30 will

result in entirely different handling characteristics unless the rockers are modified to suit the new bikes geometry. This is just a fact of lifeand its the reason that custom fork builders are still in business today. Canned solutions for chopper forks just dont work very well sinceeach bike is unique. Unfortunately most people dont know whats good and whats bad so they settle for what the mass-producers givethem and assume thats how its supposed to be even if its a really horrible ride.

Thats not going to happen to you because youre going to build your own Springer and its going to be designed for your particular bike.

Were going to start at the bottom and get this thing built for as little money as we can without sacrificing safety or quality.

Rocker to Leg Attachment

In my forty years of building Choppers I have probably seen just about every conceivable method used to mount the rockers to the legs on

Springers and no matter how bad the lash-up was I have never seen a fai lure at the rocker connections themselves and I have seen somepretty poor examples. Ive seen bikes where the rockers were connected to the legs with just regular old hardware store bolts run throughbare holes with separation provided by brass washers and some of these forks had seen hundreds of thousands of miles of use and stillworked. I wouldnt recommend this method but I just wanted to point out that almost anything can and does work. Some methods are justbetter and safer.

The weak point of Springers is not the rocker connection but the tube legs themselves and especially the junction point where the rearlegs enter the lower fork tree.

I have seen hundreds of Springers with bent and broken rear legs but in almost all cases the front (sprung) legs were not nearly as badlydamaged which goes to show where the stress points actually are on a set of Springer forks. The rear legs are the weak link in thesystem.

There are at least six basic rocker to leg mounting designs available to the builder and within these six basic arrangements there are

several variations with respect to the arrangement of the various parts.

Everybody claims that their own unique arrangement is the best but in reality all of these designs and their variations perform satisfactorilyso its up to you the prospective builder to select a system best suited to your particular applications.

Note that in the pseudo-sectional drawings to follow that we have not shown shim washers, which are typically used to adjust theclearances and compression for the bushings and thrust washers.


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The first method involves rockers that have a trunnion that houses the pivot bushing and this is the method seen on the old originalHarley rockers and many modern forks as well. This method greatly simplifies building the fork legs but makes the fabrication of therockers much more complicated. Figure 3 illustrates a stock connection configuration.

The big advantage these types of rocker have over flat-plate types is that they provide much more bearing surface so the bushings willlast much longer before needing replacement. In fact some old springers still in use today are still using their original bushings from theforties so the theory has been proven in reality.

Figure 3

The second method is a modern rendition of the old stock arrangement except a shoulder bolt replaces the stock stud. In almost allrespects this design as seen in Figure 4 is a good substitution for the factory connection.

Figure 4

The third method involves the use of what we call flat rockers. In other words rockers that are fabricated from flat steel stock with nointegral trunnions for the bushings and this is the style most often seen on old Springers from the sixties and seventies and the basicconstruction is shown in Figure 5.


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Figure 5

The fourth method also involves flat rockers but adds a trunnion or boss to the ends of the Springer tube legs instead of a flat tab tohouse the bushings as shown in Figure 6. This is a nice way to finish off the ends of the tube legs but since the sleeves protrude a little

into the space between the legs it does reduce the space available for the wheel so its typically only seen on wider Springers.

Figure 6

Figure 7 illustrates another popular alternative on this theme but in this case the shoulder bolt actually threads into the rocker so the boltand rocker both rotate within the bushings inside of the sleeve welded to the tube leg.

Figure 7

Figure 8 depicts a method popular in the sixties and still used today by many builders. The sleeve bolt is usually custom-made but theywere available from Paughco at one time and perhaps still are. This is the same arrangement youll most often find on the forks thatSugar Bear builds. Its very clean and the relatively flat fastener heads leave plenty of clearance for disc brakes on a wider hub than youcan usually run with other connection methods.


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Figure 8

As already mentioned there are numerous variations on each of the basic schemes just outlined. I dont think any particular arrangementis better than another. They all work just fine so pick one thats easy for you to build and go with it.

There are several methods we havent illustrated since their construction is obvious, like the method used by Redneck Engineering forinstance.

If youve already considered building a Springer I assume that youve also already purchased plans from Crime Scene Choppers, BCCOrlando, and the several others out there selling Springer plans. I also figure that youve probably downloaded our free Springer plans aswell. You can see the wide variation in design used by the different suppliers just by an examination of the various plans. If you visit

various Chopper web sites youll see even more variations in rocker/leg connection designs. The possible combinations are perhapsendless as every builder tries to improve on the work of others in an attempt to perfect the ultimate configuration. This is somewhat ironicconsidering that the old original design has been in reliable and economically practical service for over 50 years with few problemsbeyond owner neglect.

The reason Ive gone into so much detail about this particular aspect of Springer design is because there are so many variations. Itslooks complicated, and to a point it is as there are certain engineering and fabrications constraints that apply to any single arrangement.

Before you start your project I want you to go out and look at bikes at shows that have Springers installed. Take a critical look at therocker connections you see. Try to reverse engineer them in your own mind. You can look at my drawings all day long and they wontmake nearly as much sense as seeing the real thing up close and personal. In my opinion this single aspect of Springer design is themost critical but more often than not it the last thing people normally consider when they first begin to approach a new project.

Figure 9 shows a very old Springer, most likely built between 1966 and 1969, that uses flat rockers and flat rocker mounting tabs on theends of the legs. There are no trunnions at all. According to the various Internet discussion board Springer experts this particular

arrangement cant possibly work to begin with but I know the history of these forks and can say with certainty that they have just a littleunder 150,000 miles on them without any rebuilding of any kind and are still very tight even though the bronze thrust washers are wornalmost paper thin.

Figure 9

You have to excuse the axle bolt as we didnt have an axle that would fit when we took this picture but you get the idea of what Im tryingto convey.

This is a very good example of flat rockers mounted to flat tabs on the tube legs and well dissect these rockers later on in the article, asthey are a classic example of why modern experts on Chopper fabrication cant be taken to seriously. There is a bushing in there but youcant see it once the parts are bolted up.

Figure 10 shows a mockup using a stock H-D Springer rocker stud which is shown in the exploded sectional drawing labeled figure 3.


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Figure 10

Basically this stud has a short shaft on one end with an unthreaded portion that is very near 5/16 of an inch in length and then a threadedsection about one half inches long. The stud mounts to the 5/16 thick pivot tab, shown here as a piece of 5/16 x 1.5 steel strap stock, by

just being inserted into a 1/2 diameter hole in the pivot tab at the end of the fork leg. A nut and lock washer secures the stud in place. Therocker trunnion slides down over the bushing and is secured in place by the large diameter hex head bolt and lock washer.

This system is relatively primitive but its cheap and easy to duplicate and it does work very well as history can testify. If you decide to gowith this route you can also use stock H-D rockers from the old flathead Big-Twin bikes.

This will save you a huge amount of fabrication time but will also cost you about $165 for the studs, bushings and rockers.

There is however a way to replicate the easy fabrication method adopted by the factory and save about a hundred dollars at the sametime and this is to substitute readily available shoulder bolts for the fancy machined studs and special rockers.

There are two ways of doing this and well show both methods. Keep in mind that what follows is just a mockup so dont pay any attentionto the size of the particular fasteners. Well get into specifics later. For now this is just meant to illustrate the general methods that can beused.

Figure 11

Figure 11 shows one method utilizing a standard shoulder bolt. The threaded portion of the shank is placed through an unthread hole inthe pivot plate that welds into the tube end. The bolt is pulled up tight with a jam nut and topped off with a cap nut for the sake ofappearance. The bushing and rocker ride on the shaft of this bolt. This method is almost identical in every respect to a stock factoryarrangement but far cheaper and easier to implement.

The downside to this method is that any shear stresses are placed on the bolt at a point of its smallest diameter. This is also a problemwith the factory installation although I have never heard of a stud ever being sheared off.

Another method simply reverses the shoulder bolt but more than doubles its load carrying capacity as seen in figure 12.


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Figure 12

In this particular snapshot that is a smaller shoulder bolt than shown above but I was too lazy to drill the hole in the pivot plate out to thelarger size. The concept still applies but I do not recommend that you use smaller bolts.

As you can see what weve done is to bore a hole in the pivot plate, the tab thats welded into the bottom of the tube legs, thats the samediameter as the shoulder bolt. By doing so the shear stress is now applied to the bolt at its largest diameter. This makes for an incrediblystrong connection with respect to bending loads as well as shear loads. This method is about three times stronger than either the method

shown in Figure 11 or the stock factory setup.

The bushings were using in these mockups are just very cheap plain bronze material but for the real thing you need to use at a minimumSAE 841 bronze (oilite) bushings which are not only much better at resisting impact loads but also much more precise in dimensionalcharacteristics (plus or minus 0.005).

Figure 13

The rocker bushing and rocker are then slipped over the exposed portion of the shoulder bolt shaft and secured with either a jam nut andcap nut, or a lock washer and cap nut. Well get onto detailed descriptions of specific fastening methods later on.

This is the method well be using for this specific project to mount the rockers to the fork tubes since its probably the easiest andcheapest for the home-based builder to fabricate and implement. Its not the ultimate setup but it works very well, is easy to maintain,cheap and easy to implement and very strong. Its also a very flexible method and allows room for improvements and refinements overtime if you decide to build rockers having trunnions some day. Its very easy to simply change out the bolts for another size so yourenever locked into a specific design element as you are with some other connection methods.

Rocker Geometry

Once you decide on how you want to secure the rockers to the tube leg tabs it time to decide on what the rockers look like and how theyrelate to the forks and the wheel axle from a geometric standpoint.

Even a quick look around the Internet and a trip through a couple of bike shows will reveal the wide variety of shapes and sizes seen incustom Springer rockers. They range from mild to wild and even super-wild. Unfortunately about 90% of the designs youll see weredeveloped purely for looks and have nothing to do with improving the handling characteristics of the forks. In fact some designs, eventhose that appear to be conservative or traditional, actually hurt the steering and suspension geometry. Equally surprising is that somedesigns that appear to be ultra radical in appearance were actually designed specifically to improve handling. For this reason one cantgo by looks alone.


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Figure 14

Figure 14 is my so-called standard rocker shown in the loaded condition, which means supporting the weight of the bike plus the rider.Note that the axle is about 1 higher than the rear leg pivot point.

This is a somewhat extended rocker design but its not radical. By pushing the axle 1.375 further forward than a stock rocker it permitsthe use of a wider hub in a narrow set of fork tubes and reduces trail to 2.625-inches on a bike with a 40-degree neck.

Figure 15 is another design I use quite often. It is virtually identical to the standard pattern with the exception of the axle location. Note howmuch higher the axle axis is located relative to the rear pivot point. It is also 1-inch further forward reducing trail even more.

In general the higher the axle axis is relative to the rear leg rocker pivot point the less tendency for the front wheel to flop. Its acombination of geometry and weight distribution that reduces flop but the biggest factor is weight; that is, the more weight you have below

the axle axis the less likely the wheel is to suddenly flop. By placing the ends of the fork tubes, the rockers and the associated hardwarebelow the axle line youve lowered the center of gravity of the wheel assembly relative to the rotation axis. This is one of the primaryreasons why bikes having scimitar type rockers behave so well despite their radical appearance; they just have a lot of weight below theaxle axis. Of course the same anti-flop elements can be accomplished by just running a lightweight wheel and tire to begin with in the firstplace and then you dont need to worry about anything else but for some reason in this day and age simple stuff like this seems to get lostsomewhere.

Figure 15

Figure 16 represents a stylized sketch of what we used to call Scimitar rockers that were popularized in the early sixties and still builttoday by Sugar Bear and a few others.


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Figure 16

If you take the time to look at Springer geometry over a wide range of neck rakes youll soon find that there is a mathematical relationshipbetween the values for trail and the location of the axle axis relative to the rear leg rocker pivot point. If you make a plot youll end up withsomething very similar to that shown above.

If the curve is drawn accurately it closely resembles a segment of whats called a Fibonacci spiral but this gives you some idea of howand why such rockers were developed. In practice their effectiveness really doesnt come into play until you start building long forks for

bikes with fairly deep neck rakes. Figuring all this stuff out will keep you busy for a couple of decades so good luck if this is the directionyou want to follow.

Most custom builders have developed a comprehensive number of patterns over the years that suit a wide variety of fork geometries andbike configurations. Weve included three different patterns with the plans that work well on our particular fork designs and with mostchoppers having necks raked from 35 to 42 degrees. There is always room for improvement and experimentation so dont be afraid to tryout several different configurations for your particular project. If you accept the factory stuff youre only cheating yourself.

On this build-up were going to make two different sets of rockers. One set will be very simple and another set will be a little fancier andtake longer to make.

For the simple set all we need is some 1/2 thick steel strap 1.5-inches wide and about 14-inches long. We cut this in half and have twostraight segments (the cutting pattern is at the end of this article). The overall dimensions are shown below.

Were going to be using 5/8 shoulder bolts with 3/4" bushings so we bore two 3/4 diameter holes in each rocker for the pivot pins. Sincethis is a narrow Springer its likely that youll be using a small spool hub wheel or one of the mini-brake hubs and both normally use 5/8

axles so bore the axle holes with a 21/32nd drill bit. At this point, if you want, you can hold off drilling for the axle until you finally get thewheel and axle you actually want to use.


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Figure 17

Figure 17 shows the various parts in the progress of being shaped and sanded down prior to being finished. They dont look to pretty nowbut well dress them up a little as we go along.

Even thought these rockers are about as simple as one can build they work just as well as some fancy curvy design but they do needmore clearance with the tube leg termination caps than a sculpted or radiused type of rocker. You may have to grind a deep scallop onthe upper inside edge to provide clearance for the tube leg as the rocker moves through its complete cycle.

Once the rockers are finished Ill usually cut the pivot point tabs that weld up into the tubing of the front and rear legs. I normally makethese from 3/8 by 2 cold-rolled strap but all I had in the shop was some hot-rolled. Please dont try to use this stuff, as it just takes to longto get a good finish on it.

I do the rough cutting with a saber saw or a reciprocal saw as can be seen in the piece to the left in figure 18 and then dress down thesharp corners with a belt sander to the rough shape as seen on the tab to the right in the snapshot.

I do the final shaping and polishing later on at the same time as Im fitting the tabs into the tube legs. I use the same tabs for all projects,Girders, Leafers and Springers and have a different pattern for various tubing sizes. The patterns are included in the drawings and at theend of this article.

Its not shown but once I have the tabs roughed out I usually drill a -inch pilot hole at the pivot point location.

Figure 18

Whenever youre working on parts that have mates so to speak it pays to sometimes drill extra indexing holes and stack the rough-cutparts so that you can grind, shape and dress all of the separate pieces against a master that youre satisfied with. The index holes canbe plugged and welded closed if necessary later on in the fabrication process.

Figure 19 shows a set of pivot tabs being shaped.


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Figure 19

The piece on the top is my master and the piece on the bottom is in the process of being shaped on the belt sander. The goal is toeventually end up with both pieces being virtually identical in all respects.

Figure 20

Figure 20 shows the backside of the same pieces where were getting close to matching the profile after some sanding.

The big disadvantage we home based builders usually have is not having any fancy machine tools so each and every part we cut isactually a one-off. We spend a lot of time trying to make all of the parts identical and we do this with blood, sweat and tears. It takes a lotof time and a lot of labor.

Fortunately we dont pay ourselves so we can afford to take the time to make things right even though it may be a lengthy process. At one

time garage-based building got a bad name because people werent taking the time to do things right and just slapped things togetheras fast as possible. Thankfully those trends are gone and most home-built choppers today are just as good, if not a lot better, thananything being made by the manufacturers.

Always remember that you only get back what youre willing to put in and you cant go wrong.

After the tabs are roughed out Ill cut the notches in the tube legs. I normally keep a small supply of tubing on hand precut in 2-inchincrements for the more common Springer lengths. I always use DOM tubing on Springer legs. ERW is perfectly fine for Girders andLeafers but Springer legs take a lot more abuse plus we often have to add threaded slugs or pivot bungs inside the tubes so we need anice accurate inside dimension that DOM provides.

I still cut all of the notches with a hand held mini grinder using an abrasive disc. Id probably still do it this way even if I had a millingmachine since it just takes a few minutes to do all four legs.

I normally skip the first step shown below but to do this properly you really should start the notches by drilling a 3/8 diameter hole (to

match the tab material thickness) completely through the tubes exactly on center as shown in Figure 21.

You can see my layout marks in felt marker pen.


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Figure 21

The finished product should look like figure 22.

Figure 22

Cut the notches with the grinder. You can clamp on a section of angle or channel to serve as a straight edge if you need to. The cutsshould be clean and straight and slightly less in width than needed for the 3/8 tabs.

Figure 23

Figure 23 shows the initial cuts. Note that the notch is smaller in width than whats required. To do the final dressing I use a large piece of3/8 strap material and the grinder to slowly and carefully widen the notch until the strap will just barely slip into place. Using this ratherlarge piece of steel makes it much easier to see if the notch is trying to veer off center when you sight down the tube from the end to end.


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Figure 24

Once you have a nice tight fit you can square up the ends of the notch where the drilled hole was by just using some hand files. Well addthe bevels for welding later on as were doing the final fitting on the pivot point tabs.

Once the slots are cut nice and straight we can go back and do the final rough work on the pivot point tabs. Figure 25 shows how muchweve cut down the pivot point tabs since we initially roughed them out earlier. At each step were getting closer to the final product but ittakes time when youre doing this with relatively primitive tools.

Figure 25

Everything is an iterative process where you work on the various bits and pieces a little at a time until all the parts are nearly ready for thefinal assembly. Many pieces wont actually reach their final stage of shaping until after everything is assembled.

Figure 26

I kind of break the work of making these small parts into several stages. The first is what I call hacking for lack of a better description.

Thats the stage where you take the chop saw, reciprocal saw, saber saw, mini-grinder or whatever and slice away cutting off as muchstock as possible to get somewhat close to your pattern outline. The next stage is what I call rough shaping where Ill use a grinder andbelt sander to knock down the sharp edges and corners working the piece down even closer to the pattern outline. This is the stagewhere any contours are developed and youve got a crude outline of the part. The next stage is what I call dressing and this is where you

use the belt sander to bring the part down to almost touching your pattern outline maybe being just a 32nd of an inch shy of being perfect. Ido 95% of all my layout, fixturing and trial fitting while the parts are in the rough stage saving the dressing until Im almost ready to start


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.completion prior to painting or plating.

Almost all of the parts shown above are in the early rough shaping phase so the contours havent been fully developed yet.

Getting back to the pivot point tabs there are several ways to finish the raw ends of the leg tubing where it meets the flat plate stock. Manybuilders like to use tubing caps and these do work well. Usually they are welded on before you cut the notches. Other folks just weld in asmall segment of 3/16-inch plate set at a 45-degree angle that is cheap and fast but doesnt look to great. I was taught to use what we callbullets to finish the ends.

Figure 27

A bullet is just a wedge shaped piece of tubing that gives the tube end a nice tapered transition down into a piece of flat stock.Depending on what angle you cut the bullet it can be long or short and thats up to you. The welds around the bullet are purely cosmetic sodont be afraid to grind them down into a nice transition.

I personally like long bullets which create the look of a very long taper but to use these effectively you have to have very deep legs on thetabs youre welding into the tube legs and this takes a lot of time to do.

Figure 28

This gives you an idea of what a long bullet might look like on a typical tube leg. Notice how deep youd have to make the plate so that it


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had at least 2-inches of good structural weld before the bullet starts. On a custom bike it might be worth the work.

When I first started working in a chopper shop cutting bullets was all that I did all day long. I think I was making $1.25 and hour and myboss sold the pieces for a dollar each and he was selling hundreds a week to shops all around the country. I got to where I could cut anddress about 20 an hour so he was doing pretty good on these little beauties.

I still like bullets but to be effective from a time standpoint they can only be about 1.5 inches long. I think regular tube caps look like somekind of crap that a manufacturer would use.

You can also create what I call a coved tube end that wraps around the rocker but its even more work so Ill leave that one for a later day,maybe a discussion board item.

Remember that no matter what type of tube-end termination you use it is vitally important that you leave enough clearance between thelower portion of the cap or bullet and the upper inner edge of the rocker so that rocker can cycle through a full range of travel withouthitting your tube cap. This seems like a logical matter but youd be surprised how many people dont think about the rocker movementwhen theyre capping the tube ends.

Figure 29

Heres a rocker mounted in a mockup. Imagine that it swivels around the axis point in a up and down direction and youll soon notice thatin the arc of travel it gets very close to the full diameter of the tube leg that occurs just above the cap. This is why you need plenty ofclearance between the end of the termination cap and the uppermost edge of the rocker bearing washer or bushing or even the rockeritself, especially if youre using flat style rockers. This will come back to bite you if not accounted for which is why Ive tried to restate thesituation and make it as clear as possible. Dont be afraid to make your tabs a little on the long side. In fact they actually look better if

theres about a half inch of clear space between the rocker and the termination of the leg cap. The leg in this picture is very tight and Ishould have scraped it but it works but just barely.

Tab Welding Fixture

With the pivot point tabs being close to finished its time to give them a trial fit in the tube legs. Id actually hold off welding them until laterin the progress of the project but since this segment of the work is related Im showing it here somewhat out of sequence.

I was taught that you never build a jig for anything where a simple fixture would do just as well so for welding tabs into tubes I was shownthis simple method I still use today.

This utilizes the materials themselves to become almost self-aligning so its really hard to make a mistake.


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Figure 30

Basically this consist of using two sections of 1x1/2 steel channel which is available at most hardware stores or builders outlets. You drillholes near the ends of the channel that match your pivot pin size. Needless to say the holes have to be exactly on the centerline of thechannel. A piece of dowel is run through the upper channel, through the pivot tab and into the hole on the lower channel. A level on theupper channel insures that the tube leg and the tab are aligned in both directions and perfectly plumb and square.

The snapshot below shows the set up in a little more detail. You can add precision washers top and bottom to center the tab with thetubing in the transverse direction but Ive found that if the notches were cut accurately this isnt really necessary.

Figure 31

With minor modifications this fixture and be made to handle multiple connections if youre doing a lot of similar items but for the homebuilder doing each leg one at a time is good enough.

Pre-tacking the tabs in place using this fixture makes it a lot easier to get everything aligned down the road when were ready to do thefinal welding on the entire fork assembly. If these tabs are tacked plumb and square with the tube legs then everything else can be basedon the relationship of these parts. Ironically they are the smallest but most important parts of the entire fork assembly. If these tabs are

crooked or skewed or cockeyed in the least bit youre up shit creek so take the time to do it right.

I make both the rear and front legs at the same time and do all of the final welding for the tabs and tube caps or bullets at a single sitting.Just make sure to leave the tube legs longer than you anticipate using on the final set of forks.

Spring Pedestal

The Spring Pedestal, sometimes called the Fork Bridge, and also the Cross Bar, is that relatively short structure that connects the twofront legs together at the top where the lower springs and spring rods mount to the legs. This should not be confused with the SpringPerch which will be described elsewhere.


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,particular piece. What were using is the simplest method since this is supposed to be a low-buck straightforward project.

To begin with we need a section of 1x1 cold-rolled steel bar stock about 8 long. To make the spring pads we need a short 6 longsection of 3/8x3 cold-rolled steel strap. (Actually 5/16 material works just as well and in many ways looks better).

We make the spring pads by simply drilling two circles out of the 3/8 material using a 2-1/4 hole saw as seen below.

Figure 32

This will give us two nice pads having an outside diameter of almost exactly 2-1/8 inches since you have to subtract the wall thickness ofthe hole saw and this is exactly what we want to match our springs. Verify the diameter of the springs you will be using and makeadjustments as required.

Figure 33

Using a 1 hole saw we make a cut at each end of the cross bar using our 6.5 center-to-center dimension shown on the plans betweenthe front fork legs. This creates the pockets where the tube legs will eventually be welded. Add a fat sixteenth to this length for weldingshrinkage.


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Figure 34

We then drill two 1/4" pilot holes for the spring rods at 3 on center as can be seen above.

The two short sections of tubing are there just to illustrate how the cross bar fits between the front fork legs and are not part of the finalassembly.

When were finished well weld the round spring pads to the spring pedestal and once its welded between the tube legs well have anassembly that looks like Figure 35 below.

Figure 35

Remember that the short sections of tube are just representational and not part of the assembly itself.

Another method I use for heavier bikes is to substitute a section of 1x2 rectangular tubing for the 1x1 solid bar stock as seen below.

Figure 36

This creates a very strong and clean arrangement but it does take longer to fabricate since you have to weld solid plugs below the springpads that are drilled and taper reamed to match the spring rod ends.

Once I have the pedestal roughed out I typically enlarge the -inch pilot holes to 3/8-inch diameter and then using a taper reamer theholes are slowly and carefully enlarged to match the final dimensions of the spring rod tapers. For the rods we purchased the taper is -inch per foot and the small end diameter is .4375 and the large diameter is .5-inches.

You can do this with a hand held reamer but it will take almost forever so invest in a good drill driven reamer or take the parts to a localmachinist. The fit should be as close to perfect as possible as its the taper on the rods that prevent the springs from simply pushing the

rods through the pedestal.

In my opinion this is one of the best design characteristic Harley came up with for the old original Springer but some modern buildersprefer to just use regular straight rod with threaded ends that screw into taped holes in the cross bar.


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Figure 37

You can see the slight taper on the ends of these stock H-D spring rods and weve tapered the bores through the spring pedestal tomatch. The nuts that come with these rods are special heat-treated material so always buy a complete set and not just the rods alone.

It is somewhat of a pain to use these original H-D designed tapered spring rods but its worth the trouble as youll never have a problemwith the rods pulling threads which is a relatively common problem on the cheaper method used by many builders. Once you do one setand get used to using the reamer it goes faster but the first project can be touchy since you have to be so careful not the ream out thepockets to much. The goal is that when viewed from the bottom with the rod in place, at least one thread is still up inside the pocket orright at the edge of the hole. This indicates that the taper is nearly perfect and should last for a couple of lifetimes. The nuts should betorqued to 20 ft. lbs. (14 ft. lbs. if loc-tite is used.

Figure 38

Figure 38 shows the spring pedestal after weve welded the spring pads in place and are in the process of fine-tuning the tapers for therods. The blue tape reminds me which hole still needs some work.

Figure 39


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Figure 39 is just another shot with the main springs set in place. You can buy all of these parts already chrome plated but this is a budgetproject that will be painted or powder coated so we opted for a Parkerized finish.

What isnt shown here, since I dont have any yet, is the aluminum or bronze stepped washers that serve to keep the springs centered onthe pads and act as bearing plates to prevent wear on the springs and the steel pads.

As you can see were working from the bottom to the top and so far we havent really needed any special tools beyond the taper reamerand were still a ways away from having to build an assembly and welding jig.

From my standpoint, coming from how I started with choppers, the whole thing about these bikes is that they were originally intended torepresent their owner which in the old days was the also the builder. It didnt make much difference if you were a good builder or a badbuilder. The whole deal was just about building your own stuff no matter how it looked or what other people thought about it. Even today Icant understand why anybody who wants to own a real chopper would even consider letting anybody else build their parts but this attitudecomes from my upbringing so I cant help it. I realize that in todays society a bike doesnt have the same importance as it once did andthat not everybody has the time or the resources to do everything themselves so it pays to take advantage of the other people out therewho can help with a project. Farm out the stuff you cant do at home but to be honest I dont think there is anything involved with building agood set of Springer forks that almost anybody cant do in their own garage with a few simple tools. If its your bike do you wantsomebody elses forks on it?

Fork Trees and Spring Perch

These are usually the parts that most people say they cant possibly build at home since they dont have any fancy machine tools. I say

that these are actually the easiest parts to build at home.

You start out with a slab of 3/4 thick steel and then make it do your bidding with whatever tools you have at hand. I have known people tocut the trees with nothing more than a hacksaw and at least one guy who carved them out using a hand held mini-grinder so anything ispossible. If you have access to a reciprocal saw youre in like Flint as this tool will make short work of cutting this material. Rent one if youhave to.

The secret to cutting thick stock is to make short and fast passes whittling away the excess material in small straight cuts working downtowards the outline of your pattern one little section at a time. You can make 5 or 6 small cuts in thick material about twice as fast as tryingto make one or two big cuts. If your using a reciprocal saw you also need a blade with an aggressive tooth count. The mistake mostpeople make is to buy a blade designed to cut sheet metal with a tooth count in the range of 12 to 14 when what you really need for thickstuff is a tooth count more like 8 or 10 and 8 is preferred for sure.

Dont try to follow any contours in the pattern as attempting to bend the path of the blade will only slow down the cut or break the blade.Make a series of short cuts that approximate the curve youre trying to follow. You do the blending with a grinder or belt sander later on.

Figure 40

Stick the material in a vice or clamp i t to your bench top and start whacking at it. Youll be amazed at how fast it goes. The whole secret isin the blade selection and you absolutely need to have a relatively course (and short) blade.

Believe me when I say that cutting this thick material is easy and fast if you have the right blade and I would not hesitate even for amoment cutting stock as thick as 1.5 inches using this method. Its far superior to using a cutting torch and vastly less expensive thanhaving parts farmed out to be plasma cut or cut on a water-jet machine.

The Rude and Crude Old School trees are about as simple as you can get. In the old days we just used to square off the ends and cut thestock with a hack saw. Basically you start out with some 3/4 thick by 2 cold-rolled strap and cut it into two short 8.5-inch sections.

There is zero offset in these trees so all of the holes are in the same line. Nothing gets as simple as this and these are exactly the sametype of trees the factory first built back in the twenties and thirties for their own Springers.

Figure 42 shows the trees in two different stages. The lower tree, which is at the top of the picture, has just been roughed out with the


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. , ,of being shaped to the final contour with the ends being radiused and weve bored the holes for the tube legs and stem with a hole saw.

Figure 41

Many people think that trees with zero offset are somehow inferior to so-called modern trees than can sometimes have offsets in thearea of 2.5-inches but this is just an old wives tale and in almost all cases the less offset one has to have in a set of forks the better thebike will handle especially if it has a steeply raked neck.

Figure 42

After we got these trees to the rough shaping stage it just looked to me as if this whole deal was just way to simple and perhaps kind ofboring for most of the readers so I decided to make another set of trees that are far more complicated to fabricate. There is nothingwrong with what we started out with. These are great trees and I plan to use them on a little Bobber but to mix things up we decided toshow how to use our narrow Springer trees instead as it involves a lot more work. All of the following procedures are identical its just thatwere using a slightly more complex set of trees on the project. You can build your forks using either design and the only difference will bein the offset. Even the spring perch is identical for either set of trees.

Figure 43

As you can see from the pattern these trees are going to be more challenging to work on but actually not any harder to make even thoughit will take more time.


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Figure 44

Here are our two narrow CBH trees, in figure 44, after only a few minutes of taking the rough blanks down to size with a multitude of smallshort cuts. If youre really good and really patient you can keep making small nibbles with the saw and get these blanks almost toperfection using just the saw. I personally dont have any patience so Ill do the rough shaping on the belt sander and with a grinder.

Generally I try to drill at least the pilot holes for all the bores in trees while they are still in the square before I cut the shapes out but thesewere so simple I just went ahead and chopped them out.

Drilling this material isnt hard its just a little slow and you do need nice sharp bits to get clean bores. For the larger holes I still use holesaws. Be sure to use a good quality lubricant whether youre using bits or hole saws. I prefer the wax sticks for lube and regular old spray-can WD-40 as a coolant.

Figure 45

Remember that the bore in the upper tree for the stem nut is 1.25-inches and the hole in the lower tree for the steering stem is 1-inch. Tryto hold off dri lling that bottom hole until you actually have your stem so you can get an accurate measurement.

On this Springer the legs are 1.25 tubing so the tube bores are cut with a 1.25 hole saw so the holes will be very tight. To get a littleclearance use some emery cloth wrapped around a dowel rod but dont go overboard. (The leg hole size in the upper will depend on how

you decide to attach the tree to the legs).

Figure 46

In figure 44 the tree in the foreground is in the process of being final shaped to match our cardboard pattern. Note that the sides are


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already becoming very smooth. The tree in the background is being rough shaped and so far only the corners have been knocked downand were working on blending the right hand radius and working down the right hand side of the flat area between the rounded ears.When they are finished they will look almost as good as any fancy machined set of trees and cost about $10 each for the material.

Upper Tree Configuration

There are two basic ways of building the upper (top) tree. One involves the use of so-called blind-bores or counter-bores and the other

is a simple full through bore for the tube legs.

A blind-bore simply involves counter-boring the tree to accept the tube legs and this counter-bore only goes about 1/2-inch deep. This isthe method we show on the fancy version of the standard CBH Springer trees. It involves machine work that the average garage-basedbuilder isnt likely to have access to. There is a work-around called the shade tree counter bore. This is pretty crude but it works everytime so dont laugh at it until youve tried it.

You bore the tube leg holes in the top tree all the way through with a 1.25 hole saw and then you cut two plugs with a 1.375 hole saw outof 1/4 or 3/8-inch material so that the plugs are just a wee bit shy of being 1.25-inches in diameter.

Figure 47

You weld these plugs into the holes in the top tree, flush with the upper-most surface as seen in the mock-up shown in figure 48.

Figure 48

You end up with a nice recess in the top tree thats exactly like a fancy machined counter-bore as seen in this mock-up snapshot of theunderside in figure 49.


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Figure 49

Make sure you have a really deep welding bevel on both the tree bores and the plugs as the top surface and the crown of the weld beadwill be sanded off smooth during finishing. You do not do any welding on the inside bore, as it needs to have a clean and sharp recess.

After welding and final grinding and sanding to get a perfectly smooth and seamless surface on the tree you can drill the boltholes in theplugs to the final dimensions for your cap screws.

The full-bore method involves drilling the top tree tube hole to match the outside diameter of a lug welded into the leg tubing. In mostcases the lug is 1-inch in diameter. The tree itself is secured to the tube leg with large washer and a bolt into this threaded lug. There areadvantages to this method as the tree is not locked to any particular steering neck dimension and can float by up to three eighths of an

inch pretty easily just by using some stainless steel shim washers under the bolt head or around the lug. This is the method I suggest forthe first time project since it provides some flexibility during fabrication and at least a little adjustability afterwards. In many cases the 1-inch lug will need a short section on the bottom turned down in a lath to match the inside diameter of your leg tubing.

Figure 50

Figure 50 illustrates a mock up showing how this method works in practice. The top tree is bored to match the diameter of the lug andwhen installed rests on the shoulder created by the diameter of the main leg tubing shown here by the short section of 1.25 tube on thebottom. The tree is secured with either a bolt or a nut. Off course you would use a nice chrome or stainless washer instead of the zinc oneshown here.

Figure 51

Figure 51 shows a mockup up using a threaded insert inside a hollow lug (plug welded in practice).

Figure 52 shows an alternate method where a shoulder bolt is welded inside a hollow lug, which in turn is welded inside the tubing leg.

Using some imagination you can usually come up with a simple method suited to your particular project that doesnt involve any machinework.


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Figure 52

Lower Tree Installation

One of most important and perhaps the most critical aspect of building a Springer is knowing where to weld the lower tree to the tubelegs. On most plans, including mine, this magic dimension is usually shown as to be verified by the builder. The reason for this is thatthere is no way of me knowing what the dimensions are of your particular steering neck assembly. There are standards for thismeasurement but unfortunately almost nobody including the factory actually adheres to these standards.

In a perfect world where everybody plays by the rules the length of a standard big twin steering neck is 5.625-inches. On each end of theneck are pressed in place bearing cups, usually called neck cups. These cups once installed are supposed to add another .75-inches ateach end of the neck for a total finished length of 7.125-inches.

The bearing cones when installed will stand proud of this dimension by another sixteenth of an inch on each end and we have to add inthe dust shields which adds another sixteenth so we end up with 7.3125-inches. On top of this we have to add in the bearing adjuster nutthat is usually .3125-inches to the shoulder for a total of 7.625 inches needed between the upper surface of the lower tree and the lower

surface of the upper tree at an absolute minimum.You can see the bearing adjuster nut in figure 48. Note that it has a shoulder on the upper surface and this shoulder rides inside the 1.25-inch bore we put in the upper tree. If the trees are properly spaced the upper will not actually bear down on this nut but will be about onesixteenth to three thirty-seconds of an inch clear of touching the index surface below the shoulder protrusion. If the tree actually bearsdown on the nut it will potentially loosen and tighten every time the forks are turned.

Figure 53

Most custom builders set this inside height between trees at 7.75-inches but many aftermarket manufacturers set this measurement at 8-inches. You can use either measurement but the point Im trying to make here is that you really need to know what this dimension is onyour particular build especially if youre using some weird aftermarket custom wiz-bang steering neck that a lot of people are selling sincethey look cool. Eight inches clear is usually the safe bet if you have to build without being able to actually measure the neck on a

particular bike. Minor adjustments can be made with shim washers if necessary.


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Figure 54

You can see the shoulder of the adjuster nut inside the upper tree bore in figure 49 and the shoulder on the stem cap nut lying on its side.

Spring Perch

The Spring Perch is the next major item to be cut. For this set of forks the perch is made from a section of 5/8 by 6 hot-rolled steelbecause we couldnt find a suitable piece of cold-rolled as big as we needed on short notice. We transfer the cutting outline using apaper pattern taken from the plans and using the reciprocal saw we cut the perch out just like we did with the trees.

Figure 55

After the part is cut I use a small 3 belt sander to begin cleaning up the edges. A 50 grit belt works wonders and you can quickly bring thepiece down to the pattern lines. The perch, shown with the spring pedestal, is in the process of being shaped in the snapshot below.

Figure 56

At this juncture we need to decide on what type of spring rod bushing were going to use in the spring perch. I prefer the stock units sincethey have a built-in spring seat which saves a lot of work but some builders prefer to use regular old bronze bushing, either flanged orplain sleeves.


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Figure 57

The reason bushing are needed in the first place is because the spring rods, when the rockers are actuated, move up and down a fewinches so we need some way to guide and gently restrain them to a limited amount of lateral movement without creating a situation wherethey get bound up.

The spring rods dont gyrate but instead move slightly back and forth at the juncture of the spring perch so the ideal bushing would beshaped like an oval but nobody makes anything like this, including the factory, but they came up with a really neat solution which is a

bushing that sits in an semicircular seat so it can pivot slightly.

Figure 58

This snapshot shows a very good modern rendition of the bushing socket cut into a custom spring perch with a ball-end milling bit. This ofcourse is the perfect way to do it but most of us dont have access to this type of machine tooling.

A lot of builders over the years had noticed however that the old stock rod bushing will still slightly rock back and forth if i ts just placedinside a 1.25 diameter hole in the perch since the only thing restraining it is the spring and as the spring follows the path of the rod sodoes the bushing as it pivots back and forth on its flange. This is the route well be taking on this particular fork and a method weve used

for decades. It does work and it works very well and it saves a lot of time and in fact its far superior to the shortcut of using regular oldbronze bushings as many commercial builders do. Perhaps they dont realize that this shortcut actually causes the rods to bend in themiddle or maybe they just dont care.


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Figure 59

Here are the stock rod bushings set into a 1.25-inch diameter hole in the perch. Note the integral spring retainer on the stock items. If youuse the standard bronze bushing shown in the bottom of the picture you will need to make a pair of retainers.

With the perch finished and the bushing installed its time to do the trial fit of the springs, rods and forward leg spring pedestal.

Figure 60

Now the fun begins as in order to install the upper springs weve got to fully compress the lowers and its here that you really gain someappreciation into exactly how stiff those lowers really are.

I just happen to have a C-clamp large enough for this operation but you can buy or build a simple spring compressor made from two shortsections of 3/4 bar stock with 5/8 all-thread rods and nuts. If you buy a 12-inch clamp from one of the import houses I can almostguarantee that itll eventually break. There is huge amount of pent up force in these springs as they are being compressed. Even my good

American made clamp bends a little bit when I really crank in the last few turns on the handle. It takes a ton of pressure to bend 1-inchsteel so you can kind of appreciate what youre dealing with here.

This is not a casual operation as the force generated by those springs is considerable and if something slips there will be hell to pay sonever stand downstream of the springs while doing this and if you have any doubts at all about your clamps dont attempt this to beginwith until you have some kind of apparatus that you have confidence in. People have actually been killed by a mishap when doing whatlooks like a simple procedure so this isnt something to do after having a few beers some evening.

Figure 61

You can usually push the upper springs down by hand just enough to get the retainers installed. Sometimes its great to have an extra pair


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o an s or s opera on so m g y a goo ay o ave a r en come y.

Figure 62

Figure 57 shows our spring perch with the springs installed on the spring pedestal and it looks as it should with no tendency for thesprings to bind or the rods bending.

Once you get the perch finished youve finished the last of the fabrication of all of the cut parts and were ready to address the overallconfiguration of the forks but before we can start welding things together we need to get some accurate dimensions for the legs.

Tube Lengths

There has been so much misinformation posted on the Internet about tube lengths that Im having a hard time trying to figure out where to

start so that people can have a uniform basis for measuring fork length. You can visit a dozen or so web sites and each one will have theirown method of figuring out tube length. Some si tes even have fancy interactive calculators and a variety of pundits trying to explain how tomeasure for the forks for your particular build. Ninety percent of the time all of the so-called experts and high-tech computer programs arewrong and if you believe their pitch youre forks will usually be to short. This is one of the reasons why forks are the most popular itemsbeing resold on auction sites and at swap meets. Almost everybody who orders forks based upon published dimensions and computerprograms ends up with a set that is too short for their specific bike. In one case out of a thousand somebody might actually get a set that

are to long but this is extremely rare.

One of the problems is that most, if not all, of the pundits providing recommendations about forks have never actually built any to beginwith but they have some catalogs and tables that they can consult for making selections.

I have to admit that the problem cant be stacked entirely on the pundits and the published tables on the Internet as bike owners have acertain share of the responsibility in providing fork suppliers with good accurate dimensions and measurements.

Some people imagine that you can order forks for a hypothetical frame just by quoting the up and out stretch and the neck rake along withthe wheel diameter by using a set of mathematical calculations or as mentioned before, some tables from a catalog. I guarantee you thatthis doesnt work.

The old original de-facto standard for fork length is based upon the classic UL Springer which measures 19.5-inches from the top of thebottom tree (bottom of the lower bearing cup) to the center of the rear leg rocker pivot point. These old forks had zero offset and well seea little later that is an important factor.

As time progressed the FXWG fork became the standard and is still used today by almost all builders when calculating extension. Thisparticular fork was introduced in accompaniment to a new factory frame that was about 2-inches taller at the neck than earlier models tohouse the upcoming new motor.

According to the factory this fork measures 31.75-inches from the underside of the upper tree to the center of the axle hole but we have toremember that it also incorporates a 2.25-inch offset in the trees and this is important with respect to measuring real fork length.

For example lets suppose we wanted to replace our stock FXWG with a new reproduction Springer. We can translate hydraulic forkmeasurements back to Springer forks measurements by just subtracting 8-inchs from the hydraulic dimensions since Springers aremeasured to the bottom cup and hydraulics are measured to the top cup. For this example it works out that wed need a Springer thatwas 4.25 over stock (19.5) or in other words a 23.75 leg length.

If this is all that we did wed end up with a reproduction Springer that was actually to long because the originals have zero offset in the

trees. The difference comes to almost 1.875-inches on a bike with a 40-degree rake. What we really need is a Springer with a 21.875leg length or a Springer with a 2.25 offset in the trees and the 23.75 legs.

I know a guy who bought a very expensive Santee softail frame that was supposed to be 4 up and 2 out with a 40-degree neck. Heordered a very expensive custom made chrome plated Springer from a noted maker and when he finally received both the frame and theSpringer the forks were almost 4-inches to long. The reason was simple. The frame neck angle was actually closer to 38.5 degrees andthe up stretch closer to 3-inches and the out stretch was about 1.5-inches.


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The only way to get good accurate dimensions and angles is to do a full scale mockup or better yet mockup the actual frame and usesome closet rods and wooded trees to simulate the characteristics of the forks you plan on buying. Even then however you have to becareful to double-check everything.

Figure 63

Figure 58 illustrates a fairly typical chopper with a Springer Front-end. These particular forks have a one-inch offset in the trees, which ispretty common on modern custom forks. The frame is sitting level with 4.5-inches of ground clearance shown as FH (frame height) in thediagram. The front wheel/tire has a radius of 13.5-inches. The neck height shown as NH in the drawings is 32-inches measured to thelower most edge of the lower bearing cup. The rake angle, RA is 40-degrees and the neck length, NL is 8-inches. This configurationuses a Springer that has a rear leg length of 27.75-inches measured from the center of the rear rocker pivot hole to the top surface of thelower tree.

Figure 64

Figure 59 is the same bike but weve raised the front portion of the bottom rails to 5.5 ground clearance by pivoting the frame assemblyaround the rear axle axis by two degrees, which changed the neck height to 33.75-inches. This configuration uses a leg length of 31.25-inches, almost 3.5-inches longer than if the lower rails sit level. This doesnt seem to make much sense since we only raised the front ofthe frame by an inch so why do we need legs that are 3.5-inches longer?

Remember that the neck rake is relative to a line perpendicular to the ground so when we rotated the frame by 2-degrees to add a littleground clearance up front we changed the effective neck rake to 42-degrees. Two degrees is a lot of additional rake and thats why theforks need to be so much longer.

The point of this long section is to illustrate why a real mockup is necessary to get a prefect fork fit on any particular chopper. You dontactually need the trees or the forks or even the wheels to do a good mockup but you do need a frame and you have to get accuratemeasurements of the wheels and tires you propose to use. You dont even need an angle finder to determine the neck rake because yourmockup will automatically take rake into consideration.

The Mockup

The reason this section of the article is so far into the build-up is because you actually dont need to do any accurate dimensioning on thelegs until youve already made about 95% of all the parts you need for the forks. Its only when you have to finally determine the length of

-


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.garages and build on speculation leaving the tube lengths long until they find a potential customer at a show or a swap meet or via theInternet.

To do a good mockup start with your bare frame and sit it on blocks at the exact ride height you intend for the bike to have in its loadedcondition. If you have the wheels and tires this is great because you will be guaranteed that the frame height will be exact. If you dont havethe wheels and tires then go a friends house, a shop or a store and get a good measurement on a set that match what you want to use. Allyou need is the distance from the ground to the centerline of the axle hole.

Keep in mind that its a good idea to have the forward portion of the frame lower rails slightly higher than in the rear. I personally try toplace the front height, about where the down tubes begin their upward curve, about 1 to 1.5-inches higher. After the bike is finished andfully loaded and the springs take a set over time this will usually drop by at least half an inch.

The easiest, cheapest and fastest way to do a good mockup is to cut out wood templates of your proposed Springer parts. These can bereally blocky and crude looking as long as the relevant centerlines for all of the holes are accurately located.

When youre working with a bare frame you probably wont have the bearing cups installed yet so just cut some 3/4 thick spacers tosimulate the cups.

Figure 65

I did these using hole saws but they can be cut square; it really doesnt make any difference in the accuracy of the project. In practice youjust run a 1 bolt up inside the neck. You can adjust the spacing to suit your actual finished neck by adding some washers as shims.

Cut some pieces from 3/4 plywood or solid stock to roughly serve as the trees. Make sure that the borehole for the stem in relation to thecenterline of the rear leg is accurate with respect to the offset for your finished trees.

Figure 66

Heres another shot of our mockup trees installed with our wooden bearing cup spacers. You can add 1-inch washers between the treesto shim the space to exactly match your actual dimension if needed.


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Figure 67

Cut some legs from 1x2 stock with a pivot hole in the bottom. You can cut these to almost any length so long as youre sure they arelonger than your finished forks.

Figure 68

You can get as fancy as you want with the mockup and even make some wooden rockers but usually you can get a pretty good eyeballidea of whats needed to be done with the real steel without going overboard.

For this particular setup I spent about twelve dollars in wood and about thirty minutes in time cutting everything out and bolting it to theframe. It does look crude and primitive but believe me when I say that its about 1000% more accurate than anything you can do with aCAD program or some online computer program and I actually use CAD drawings every day of the week. They are not intended to be asubstitute for a mockup. With this setup I can move the frame around in the horizontal by adding or subtracting spacers to look at variouswheel/tire combinations and even see the results of using some dropped rockers or other ideas. Its far faster than trying to draw thevarious scenarios; if it works with the wood itll certainly work when we do it all in steel.

I personally dont know of any fabricator who actually uses the data derived from computer generated drawings to do their layout work sothink about this for a moment. Even if you do a fancy drawing the shop owner is going to do a mockup anyway so why shouldnt you.There is a time on every project when you have to stop dreaming and thinking and planning and actually start to do something out in thegarage otherwise youll never have anything to show for your ideas.

Heres a shot where weve made the transition from wood to steel. Its our first mockup using the actual components of the final Springer.


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Figure 69

Notice in this shot that were still using the wooden bearing cup simulation spacers since we dont want to install the real cups at thisstage of the frame fabrication.

Its hard to see in this snapshot but were not using any expensive sleeve collars to hold the tube in place but instead just using cheaphose clamps that work very well for doing the initial setup. The bolt sleeve on the clamps serves as a good stop.

Figure 70

The overall length of the tubes in steel in comparison to our wood mockup was almost perfect and the relationship of the tube pivot pointand the wheel axle is with a sixteenth of being spot on the money for the ride height were looking for.

You can tell from the dirt and primer residue that this is a trial fit. This is the type of work that the TV programs dont like to show as itmeans somebody has to do something beyond just bolting on some part to make a bike.

These same mockup techniques can be adapted for any fork system whether its a Girder, Spirdur, Leafer or Springer or even some typeof hydraulic front-end. Just make sure youve accurately accounted for the offset in your trees.

Keep in mind that on a Springer or a Leafer you can have considerable flexibility as to final ride height by making rockers with more orless curvature which changes the location of the axle hole in relation to the rear pivot point. For this reason I often make the legs almost 2-inches longer than the mockup says is necessary, especially on a bike with a lot of rake. This provides a little wiggle room if the ownerdecides to switch to 19 rims someday or switches springs to a shorter version than the 8-inchers I prefer to use.

Lower Tree Attachment

Once we have determined the length of the rear legs from the rocker pivot hole to the upper surface of the lower tree we can get that treetacked into place.

At this point you need to decide if its worth the trouble to actually build a welding jig for the forks. If youre planning on building severalsets it will probably be a good idea but for one or two sets you really dont need anything fancy. I actually dont use a jig as such but aseries of fixtures instead as Springer forks are in many ways kind of self-aligning if you watch out for any racking or twisting in the legs.


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Figure 71

My main setup is simply a pair of runners I clamp the rear legs into. Those shown are made for sections of 1 by 1 square tubing with

some 1 by 1/2-inch channels on top. This gets the legs up and off of the welding table so I can fit the lower tree and the spring perch.

Notice Ive run a rod through the pivot points on the legs to keep the legs parallel with the bore-holes in the lower tree. The upper treetemporarily holds the upper portion of the tubes. Using a level and machinist square you simply verify that each tree and the temporaryaxle rod are square to the legs and level in the transverse direction. Its hard to see in this snapshot put I also have a long rod made from1-inch DOM with a section of 1.25-inch material that I run down through the steering neck holes. I then run a piece of 3/4-inch drill roddown inside this tube and verify that the bore is exactly on center relative to the ends of the legs at the pivot holes. This entire operation isfar simpler than it sounds and if youve drilled all of your holes accurately the forks will be very nearly perfectly aligned without anytweaking at all.

Take one last check with the square and level to insure that the lower tree is plumb and square and tack it in place to each one of the rearlegs. Then repeat for squaring and tacking the spring perch and thats the end of the hard work.

Front Legs and Spring Pedestal

Building the front legs is very simple since we use the tacked together trees and rear legs as a holding fixture.

Figure 72

After the rear leg assembly is tacked up we reinstall the springs in the perch and to the pedestal for the front legs. Run some rods throughthe pivot points and install the actual rockers. Hold everything properly spaced by using shim washers and shaft collars. Use a protractoror angle finder to set your rockers at the desired angle for the no-load condition of the forks with the lower springs fully extended. Thenslip the upper ends of your front legs into their notches in the spring pedestal. Note that I just use a small bungee to apply tension so thelegs dont drop out of their sockets. Mark the legs where you want to

Clamp everything together. Verify that the front legs are parallel with the rear legs, that the rockers are at the proper angle and that the

spring pedestal is at exact right angles to both the front and rear legs and then tack the tubes to the pedestal. Its hard to see in thispicture but I have a piece of 1x1/2 running transversely under the front legs that automatically insures that they are level and square with

the c-channel.


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I can assure you that it feels pretty good to have built something like this especially considering the cost and the time it has taken.

Figure 75

Heres a shot taken from the other side showing one of the alternate trunnion style rockers in place. Note that at this stage with finalconnection for the upper tree has not been made and we wont do this last step until the bikes frame is finished and the bearings andcups are installed.

From the start to stage this work has taken about 38 man-hours spread out over the course of three weekends. About 95% of that timewas involved with cutting and shaping the various parts. The final setup, tacking and assembly only took about two hours.

Top Tree Attachment

The top tree is secured to the tube legs with bolts that threads into a taped lug welded inside the upper portion of the tubing with plugwelds. The bolts can be almost anything you want. The ones in figure 48 are 1/2-18 tube plug bolts from a stock wide glide but you canuse cap screws, button head machine bolts or virtually anything that looks good. Keep in mind however that if youre using the throughbore method of drilling the trees youll need washers at least 1.5-inches in diameter under the bolt heads.

If you dont have access to a lath youll need to pay somebody to machine the lugs but they shouldnt cost very much.

This is usually the very last thing I do on a set of forks as holding off until the end generally allows me to make a few minor adjustments.

Purchased Items

Weve already mentioned the sources for pre-manufactured items like springs and rods and bushings and retainers which brings me tom ma or com laint about buildin a S rin er and that is that ou have to bu a certain amount of stuff u -front before ou can even et off


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of square one so that you have products to verify the dimensions with.

You really cant start a Springer project unless you at least have the springs you intend to use as they form a critical part of the overalldesign. You need to know the actual diameter and length of these springs in order to make design decisions.

Unfortunately there are at less four or five basic spring sets being sold by a variety of vendors and none of them are identical. I got sofrustrated a long time ago that I just made the arbitrary decision to only use stock WL/UL spring sets which I still do but that shouldnt betaken as some kind of endorsement. You need to use what you personally prefer and modify the plans, any plans, according to the itemsyou have in hand.

I think that in the worse case scenario this means having springs that are 2 shorter and .5 less in diameter than what I specify on the

drawings so keep this mind as we go forward on this project. The spring length to some extent will determine where the spring perch iswelded to the legs.

Always measure each and every manufactured part you buy. Never take anything for granted. Just because you ordered 8-inch springs or12-inch spring rods doesnt necessarily mean that the specified dimension is accurate. In fact it seldom is. In reality 12-inch rods fromvarious makers can vary by as much as half an inch. Always use the actual field measured dimensions taken from your parts in allaspects of the fabrication and dont just blindly follow a set of plans or go by catalog measurements.

Final Welding

Ive said it before and Ill say it again. If you are not a professional welder then simply tack your components into place as best that youcan and take the forks and the jig to a welding shop you trust to do the final welding.

The welds on a Springer are minimal compared to a Girder so Id be surprised if you had to pay anybody more than a hundred bucks todo a first class professional job on your forks and even if you spend more it will be money well spent in the long run.

Pay special attention to the welds where the lower tree attaches to the rear fork tubes and use minimal heat and minimal penetration atthis juncture. In fact this connection only really needs to be welded on the upper side of the tree and not on the bottom. For several yearsnow Ive been contemplating brazing this connection or using a Nickel solder, as this is where Springers fail on a routine basis. Manypeople think that putting a solid lu

Spring Build

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