Refurbishing Bobbin Winder

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    There are three main types ofbobbin winder. Before you startto dismantle one and work on it,you firstly need to identify whichtype it is.

    And then familiarise yourselfwith how it works.

    (1) With small variations, TYPE Awas installed on 66, 99 and 15Kmodels over a long period.

    It has a winder, thread guide anda release mechanism. It is the onemost frequently seen and is themost complicated.

    For this reason, it is really usefulto have an assembled spare

    example to hand, so you can referto it as you work.

    (2) An empty bobbin is insertedon to the bobbin spindle until thesmall pin in the spindle shoulderlocates in the hole in the bobbinside plate.

    (3) When the spindle housing ispressed down, the stop latch

    snaps forward.

    (4) With this action, two thingshappen:

    (a) The rubber wheel is pressedagainst the balance wheel and...

    (b) The stop latch comes to restbetween the side plates of thebobbin and holds it in place.

    (5) As the handle is turned the

    bobbin fills with cotton, the stoplatch is forced upwards until iteventually spring releases backinto its original

    Thread GuideSpring loaded, thethread guide movesfrom side to side in asweeping movement.

    Rubber WheelPresses on the insideflange of the balance

    wheel.

    Spindle WormRevolves with thespindle, engages withthe gear teeth andturns the gear wheel.

    Cam Gear Wheel

    CamAttached underneath(and revolving with)the gear wheel, thecam pushes against

    and moves the threadlaying guide.

    Stop LatchSpring loaded tosnap into workingposition and quickrelease back to rest.

    PressureControlScrew

    Bobbin Control LeverThis part of the Stop Latchpushes backwards as thebobbin fills up.

    Spindle Shaft

    Holds the bobbin

    The bobbin winder is a separateunit screwed on to the machine,adjacent to the balance wheel.

    Its function is to wind a reserve ofcotton evenly onto an emptybobbin and (in most cases) springrelease when the bobbin is full.

    The most frequently seen typeactually performs three tasks: (1)winding (2) evenly distributing(or guiding) the thread and (3)stopping when full.

    In order to achieve this multi-tasking, the bobbin winder hasthree sets of components, springsand levers doing different jobs

    but all working in unison.

    TYPE A

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    When the handle is turned theworm on the spindle turns thethread guide gear wheel. This isfixed to a cam which pushes thethread laying guide to one side.

    (6) When the cam is at its maxi-mum diameter the thread guidelever is pushed to the right

    (7) The guide is held against theelliptical cam by a spring, sowhen the cam rotates the guidereturns with a sweeping action,distributing the cotton evenlyalong the drum of the bobbin.

    (8) On some bobbin winders thecam is fixed behind the gearwheel (as shown here) but theprincipal is the same.

    (9) The gear wheel is retained by acentral (eccentric) screw with asmall square lock nut at the back.

    It is a common mistake to remove

    the eccentric screw and gearwheel for cleaning not realisingthe adjustment between theworm and gear teeth must be setcorrectly on reassembly.

    (10) Type B has a winder andrelease mechanism but no threadguide. It was fitted to 201s andlater models of the 66, 99 & 15K.

    (11) This modification dispensedwith the complicated thread lay-ing device and introduced a baseplate bracket.

    In its simplest form the brackethas two slots that the thread istaken through.

    (12) Another variation of the base

    plate thread guide has two small -sprung loaded - tension wheels.

    (13) These base plate threadguides can be moved to the right- if the the bobbin winds tooheavily on the left side - and viceversa, then locked in position.

    There is also often a second cot-ton reel holder on the base platefor bobbin winding.

    It is important to clean this areabut be careful about oiling. Overoiling could negate the tension

    by allowing the cotton to slip.

    TYPE B

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    TYPE C

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    (14) This simple winder - withoutthread guide or release - relies onthe operator to stop when thebobbin is full.

    It uses the same brackets on thebase plate to deliver the thread tothe bobbin. When in use, theoperator pushes the arm downon to the balance wheel.

    (15) Make sure the screw holdingthe arm is tight enough to keepthe arm on the balance wheel.

    Apart from oiling, cleaning and

    checking the rubber ring, thereshould be no other problems.

    Type C has a spring fitted in thebobbin shaft which providesenough resistance to keep thebobbin in place while winding.

    It was fitted to electric machinesand recent models of the manualones.

    TYPE C

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    (1) Undo the single attachmentscrew and remove thebobbin winder assemblyfrom the machine.

    (2) Sometimes the bobbinwinder is held on by twoscrews which are only visible

    when the balance wheel isremoved.

    If the bobbin winder appears tobe in good working order, it isbetter to avoid taking it apart.

    (3) Remove the rubber wheel.

    This small rubber wheel on the

    end of the bobbin winder spindleis pressed against the balancewheel to pick up the momentumwhen the handle is turned.

    The rubber wheel has to be inperfect condition and must bereplaced if it is hard and cracked,or spongy and loose on its rim.

    (4) Clean all the componentsand lightly oil all the movingparts.

    This may be all that is necessary.Remove all traces of oil from thedrive wheel before replacing (orrenewing) the rubber wheel. Oilrots rubber - therefore do notover-oil the mechanism.

    Also, to avoid the wheels slipping,take a clean dry cloth and wipe

    the inside flange of the balancewheel where it comes into con-tact with the rubber wheel.

    If there are no problems you canre-attach the unit to the machineand move on to the next section.

    If the bobbin winder unit is reallydirty in places you cant get to, orif the components do not movesmoothly or do not perform thefunctions properly then you will

    have to dismantle it.

    Some problems with the bobbinwinder may not become appar-ent until you have reassembledthe handle and balance wheeland begun the sewing test proce-dure.

    Luckily, the most frequentlyfound and complicated bobbinwinder unit Type A, can beremoved independently.

    What follows is a breakdown ofthe most commonly found faults,of Type A and Type B, togetherwith suggestions of how to reme-dy them:

    Pin Badly Worn

    Change the bobbin winder ifyou have an available spare, oth-erwise make a note on the Netleyrefurbishment form.

    Worm Gear does not engagewith cam gear, or wont turn.

    (5) Loosen the nut at the back ofthe eccentric screw.

    Turn the screw until theworm gear engages with the camgear without binding.

    Re-tighten the nut, making surethe screw doesnt move, and re-check.

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    FAULTS & SOLUTIONS

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    Thread guide does not followthe cam.

    The answer may be a missing

    or damaged spring under thescrew in the base of the guide.

    (6) First undo the cam screwand remove the screw, nut,

    wheel and washer.

    (7) Now undo the thread guidescrew and remove the guidelever and the spring.

    When replacing the spring

    you will see that one small bentend locates in a pin hole in thelever housing the other end of thespring has a short tail.

    Put the thread guide back on topand locate the other end of thespring in the hole in the threadguide.

    The thread guide must be turned

    anticlockwise, pointing well overto the left - as it was (see 6) whenyou dismantled it.

    When you have replaced andtightened the screw, make surethe thread guide lever movesfreely with the tension from thespring.

    Replace and adjust the cam asalready explained (see 5).

    The rubber wheel does notturn when pressing on thebalance wheel.

    (8) Loosen the pressure controlscrew.

    (9) Re-tighten the screw whilstpressing the rubber wheelfirmly against the balance

    wheel.

    You may need to repeat thisuntil you get the tension betweenthe two wheels just right for easyturning action.

    The rubber wheel is stillnot pressing firmly enoughagainst the balance wheel.

    (10) Try loosening the pressure

    screw and the pivot screwvery slightly and leveringthe pressure arm upwardsusing a screwdriver

    The rubber wheel stopsturning before the bobbinis full.

    This should also be cured by

    getting the correct pressurebetween the rubber wheel andthe balance wheel

    (11) With the pressure screw andthe pivot screw very slightlyloosened tap gently down-

    wards on the pressure armwith a punch or screwdriver.

    The bobbin does not turnwith the shaft.

    If the pin on the spindleshoulder is okay (see previouspage) the bobbin may not beengaging with it.

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    This probably means the stoplatch is not holding the bobbinclose enough to the right end ofthe shaft.

    (12) Using a pair of pliers, bendthe stop latch slightly to theright.

    The winder does not lift offwhen the bobbin is full.

    This could be for one of two rea-sons:

    Hopefully, it may simply be -

    that with years of use - the stoplatch has been bent backwardsslightly and, if this is so, it is easi-ly corrected.

    (13) Bend the stop latch slightlyforward.

    When an empty bobbin isslid on the shaft and the winderpushed down in the engagedposition, there should only be avery small gap between the stoplatch and the bobbin core.

    This is to make sure the bobbinwinder will snap off before thebobbin is over-wound.

    The winder still does not liftoff when the bobbin is full.

    It may be that lifting spring ismissing or not correctly fitted

    and you will need to dismantlethe Bracket Assembly.

    14 Remove the pressure screw,then release the pivot screwand detach the assemblyfrom the bracket.

    The whole assembly is actuallypivoted and sprung at two points.The main one is the lifting spring,located in a housing at the end ofthe lifting arm.

    As with the thread guide assem-bly, this spring also has the twoends bent at right angles to locatein retaining holes.

    15 Detach latch and pressurearm from the lifting arm.

    16 Detach the latch from thepressure arm.

    Now replace any missing,

    worn or broken springs or partsand reassemble.

    17 Re-connect the latch andthe pressure arm with notension in the spring.

    The next par t is tr icky - but th i s

    t ip w i l l m ake i t a l i t t le easier :

    18 Place this sub assembly on

    the bracket and - just fornow - put the pivotal screwthrough the arm andtighten.

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    (19) Put the pressure screwthrough the slot in the armand screw tightly home intothe bracket.

    (20) Now,with the assembly heldfirmly in place, remove thepivotal screw.

    (21) Pick up frame assembly andplace spring into the deeprecess - again locating theend of the spring in the hole.

    As the complete unit is reassem-bled the long tail of the spring ispushed round to create the pres-sure to release the winder whenthe bobbin is fully wound.

    Heres a reminder of the assem-bled unit (back view) to see theultimate position of the springtail resting against the bend in

    the pressure arm.

    At this stage the spring tailcomes to rest against the shoul-der of the cutaway in the side of

    the deep recess.

    Sometimes the spring does notstay in the recess and preventsthe screw tightening properly,but with patience and practicethe whole assembly will rotateround the pivotal screw again.

    The thread does not lay

    evenly on the bobbin.

    First check that the bobbin shaftis turning the cam and that thethread guide is following the camsmoothly.

    If these are working properly,it could be that the thread guidehas been bent so that it does nottraverse the full width.

    The spring can (If youre lucky)be persuaded to fit inside therecess completely, making therest of the assembly easier.

    (22) Hold the two halves of theframe assembly together(against the pressure) andpush the pivotal screw backthrough the frame and screwinto the bracket again.

    (23) Using a pair of pliers,

    carefully bend the threadguide so that it is centredbetween the cheeks of thebobbin.

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