A Coil Winding Jig with Revolution Counter

Radio Record, Volume II, Issue 16, 2 November 1928, Page 28

A Coil Winding Jig with Revolution Counter

Useful Accessory

(SONSTRUCTORS, who frequently have to wind coils of various kinds for transformers, chokes, resistances, ete., soon find that it will pay them to construct a winding jig that may quick. ly be adapted to do any required winding. It goes without saying that such a winder must be fitted with a reliable revolution-counter capable of being thrown out of action at any time when required. Such a winder has been in use by the writer for some years, ani was recently improved in details, and a better class of counter added than was previously in use. A short description of ‘the winder will now be given With approximate dimensions as a guide, though many constructors will alter to suit their own fancy. The winder in question is arranged to run 1 to 1 ratio for careful winding of medium guage wire to about 30’s, or

thinner, where even winding is desired. When the wire is thin and run in irregularly, as on small chokes or telephone magnets, a 4 to 1 gearing is quickly brought into use, and a high speed may thus be attained. The baseboard should be lin. thick, about 19in. long, and about 8in. back to front, built so that it may be clamped to the bench in some way. The Diagrams. NO: 1 shows a general view, giving a few essential dimensions. The wood ‘used is mostl) 38-8in. thick, excepting the inch. piece to which the

dle, which is moved to the opposite three uprights are secured. The two end pieces are secured outside the end of this and the centre piece by a block, as shown. . Meccano parts are used for the metal working parts-the spindles, gear wheels, spindle coupler, and any brass collars that may be required to keep the spindle in place endways. At A and B are bearings made from a 3-8in. strip of 22’s soft brass, bent as shown at 4, and let into a slot in the wood. In order to prevent the spindle rising in these bearings a strip of 18’s brass is pivoted on a screw as shown at B, and at the other end is secured by a pin. Below the pinned end is a plate of-18’s brass to serve as a bearing for the large gear wheel (1zin. diameter), which is fitted with a short piece of spindle to connect to the han-

hole. The large wheel then gears with the pinion at B. The spindle should not be less than 3tin. from the board holding the uprights, and is 12in. long, joining up te a 2in. piece to which a handle cravic of 18’s hard brass is soldered, with a piece of spindle for a handle. A throw of 23 to 2#in. is convenient. The bearings by the handle are two holes drilled in a plate of 18’s brass about 2 x lin., screwed to top of upright. The Revolution CQounter.. A VERY useful type of counter is the "Irivo,’" which is obtainable from John .Chambers and Son, Létd., mi 5

Wellineton, for 18s. 9d., postage 3d. This counts in either direction, and registers up to 10,000, showing clear figures which are. arranged on drums in the usual way. A knob is provided, one revolution of which sets the counter at zero. It was decided to adapt this counter. to the winder in such a way that it might instantly be removed at any time for other uses. Thi« is effected as follows:-A brass pinion like that at B is secured by its setscrew and soldered to end of spindle. Then a piece of 3-Sin. (outside) brass tube is sawn off 1 1-8in. long. One en:! of this is cut with acute V-shaped serrations all round, first with a triangular file, then deepened with a hack-saw. The idea of this is to engage at any point with a small pin in the side of the counter spindle. The plain end of this tube is now soldered to the brass pinion, centring it correctly. Fig. 2 shows this. Now take a strip of metal-tin will do-5Hin. long. and width just less than the counter. Turn up fin. at X and notch to clear spindle. Put counter in place and

solder piece at back with notch to clear setting knob. Now take a block of wood 7-Sin. high, 24in. long, and width of counter. This is slotted on top with two V's meeting in the centre, to fit a 5-16 square lever L, which is pivoted on a block at back. The block. is attached to the tin strip by small serews from underneath, well sunk to give a flush surface. Two strips 3-8 square are now screwed to the platform, and between these the counter, on its holder, will slide; By pushing the lever to the left, the counter is dis: engaged from the spindle. 7 All that now remains is to take a 3-8 in. strip of 22’s brass about 33in. longs. and bend as shown in diagram 3. When the counter is engaged the lever drops into A and is held, but when the counter is disengaged the lever is raised slightly and rests on B. The 1tin. perforated meccano wheels are handy to slip on the spindle. one each side of a spool, to which they may be attached by screws. Larger formers for tuning coils may be held by larger flanges attached to these wheels.