45 Colt Chamber Reamer

by sb327

I needed a chamber reamer, so I made one. Here is the process I use. I started with square stock 1095, not because

it was the best choice, but because it is what I have.

First pic is starting cut, this cut will tell you if your ts is way out.

Next is the roughing cut.

And then the first cut on the mill. This is where starting with square stock really helps, you don't spend any time

indexing. This cut is made to take a little more than past center and deep enough to leave some meat for the cutting

edge below this one. Just visualize here. The next cutting edge you cut will make more sense because you will

index this cut toward you and you can see the relationship of the two as you cut the next one...... and so on.

The first pic here shows how I cut just past center. What this does is basically makes the cutting edge <90 to the

tangent.

The next one shows how I mark the cutting edge (part that did not get touched by mill) with a sharpie. What I am

going to do is give a little bit of relief to the back side of the cutting edge before I harden it. Marking it shows you

where you are filing, forgot to mention you do this with a file. Leave just a tad there by the cutting edge, we will

get to that part later. If you have a bur on the cutting edge, leave it. It (in my mind anyway) helps to keep from

accidentally burning the carbon out in the hardening process.

The last here shows how much I leave for later.

First here is a pic after I hardened it. You can get all the scale off, I don't.

Next is marking the part of the cutting edge you left alone before. We are going to do the same thing as before, only

this time I use a diamond whetstone, held with both hands. I cut along the cutting edge, starting with the part of the

mark furthest from the cutting edge (right side of sharpie mark in pic). I work the stone until the mark just

disappears at the cutting edge. Do not sharpen that part any more. If you left the bur on there, it will shine up just

before you get to the cutting edge and a small, fine line will appear just beside the cutting edge, sharpen until this

line disappears and you are done. There should be no sharpie mark left when this step is done. Remember to relieve

behind the edge of your tapers. The tapered parts of reamers cut more material than the rest of the reamer.

The next one shows it making a cut. (I will splain the barrel situation in a bit)

And a completed chamber.

That was just the way I do a chamber reamer. The most important steps are getting it turned on the lathe to correct

dimensions ( I usually take the last coupe of .001's off with a file in the lathe) and the final sharpening (to keep

those dimensions you started with). The milling process is not that particular, I do not measure anything in that

step. Be aware you can cut the flutes backwards, still no big deal, just turn it to the left when you use it.