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Watches - Conversions And Alterations In Movements

( Originally Published 1918 )

A VERGE with a good frame, good train wheels, and a sound case often pays to convert to a lever. An English cylinder or duplex, when the escapement has become worn, may be so altered. A pocket chronometer that has become badly damaged in the escapement will often cost many pounds to restore, and still be no better and not so strong as if converted to a lever at a quarter of the cost.

Making the New Escapement.—These are all cases in which conversion is advisable. The task is not a formidable one, and can be undertaken by any fairly good workman. An English full-plate cylinder, duplex or chronometer, is the most easy to alter. In these cases the pallet staff may be fitted to the old scape-wheel holes and the jewelling may remain as before. A new fourth wheel of a smaller diameter may be fitted, and the new scape wheel and pinion pitched as near to a right angle as possible, like Fig. 183, in which the dotted circles show the position of the old fourth wheel and scape wheel.

Scape wheels and pallets are bought in pairs matched to each other. Levers and rollers similarly matched can also be bought, but in this case, as the pallet-holes are fixed, a lever and roller must be specially made to the depth. The distance from the pallet holes to the balance holes must be measured and divided into four parts. One-fourth should be the distance from the balance staff to the ruby pin hole in the roller; the other three parts should equal from the pallet hole in the lever to the notch. This gives a ratio of lever to roller of 3 to 1.

First, procure a rough roller, or make one from steel rod. Measure and mark the ruby pin hole. Drill it and broach it true. Ordinary flatted pins are fitted in round holes. A D-shaped, half-round pin, an oval, or a triangular pin, require holes in the roller to fit them. A round hole is first drilled; then a hard steel punch of the right shape is driven in the hole. The roller edge in front of the hole can be hammered in a little to ease the punch and flatten the front of the hole. The roller can then be hardened and tempered, and turned true and flat. It should be reduced in diameter until there is a little more steel outside the pin hole than is necessary for the passing hollow. The surplus is to be trimmed off at a later stage. The hollow can be filed.

To make the lever, take a strip of lever steel and cut off a short length. Drill the centre hole, and measure and mark the position of the notch. Drill a hole there and file into it, slanting on each side to form the "horns," as in Fig 184. With a slitting file cut the notch, and open its sides true and square with a notch " side file."

Fit a brass pin in the roller and put roller and lever in the depth tool on turning arbors. Set the tool to the depth from the pivot holes in the plate. Open out the notch to depth and width. Mark and drill the guard pin hole as small as possible, and close to the bottom of the notch.

The pallet staff can be turned and fitted to the pallets and pivoted, the balance staff made, the balance mounted, the scape pinion turned and pivoted, and the wheel mounted, colleting it with gold, as this metal will enable a good rivet to be burnished on it. Broach out the centre hole of the lever to go tightly on the pallet staff up to the pallets. It is important that it should be quite tight. Put the pallets and scape wheel in the depth tool and adjust to depth accurately, leaving it just the least shade too deep. Strike this circle from the pallet hole as a centre. Put the scape pinion and fourth wheel in the depth tool, and strike another circle from the fourth wheel hole as a centre. The intersection of these circles marks the point for the top scape pivot. Drill the pivot hole, upright it in the mandrel, and mark and drill the bottom hole. Run in the scape wheel. Then put in the lever and pallets, scape wheel, and balance. Turn the lever round upon the pallet staff until it is " in angle." That is, the teeth must " drop " on the pallets at equal distances on each side of the line of centres. If the roller edge is trimmed down by trial, until when a tooth drops the guard pin just touches its edge, there will be no difficulty in getting the escapement in angle. When correct, drill the lever and pallets and pin them together. This done, the lever may be shaped up, hardened and tempered, its flats and edges polished, and the notch opened out to fit the ruby pin and polished inside. The roller can be polished on flats and edges. The flat can be done overhand on a brass polishing block. The edges may be polished in the lathe or turns. An escapement maker would use swing tools for this polishing, but the average repairer does not possess these, and would not have sufficient practice to use them properly.

The scape depth must be carefully tried to see how deep it locks, and the wheel topped in the turns until it locks as lightly as possible.

This depth is a very important one, and a minute error in drilling the pivot holes or in the registering of the depth tool is fatal to it. This is why it is advisable to pitch it just a shade deep, as the wheel can be topped to shallow it as required. Most depth tools have an error ; that is, the outside points do not accurately register the same as the inside centres. A good plan with a faulty depth tool is to reverse the runners with the points inside, and score the plate with the points in that position.

To mark the points for the banking pins, put the balance-staff and roller in, lay the lever on the top plate with the pallet-staff pivot in the top hole, and with the guard pin on either side of the roller mark just at the lever edge. Drill them a little closer than marked, and trim down the lever edges until the bankings are correct. Do not forget to poise the lever.

Three-quarter-plate Watches.—A 3/4 plate duplex or chronometer generally requires a new scape cock, as the old one is seldom the right size and shape to take the wheel and pallets. In these the new scape pinion can be run in the same holes as before, or the old pinion can sometimes be used again. If a very small wheel and pallets are used, a right-angled escapement can be made, though sometimes this is not possible. In such a case the lever has to be " dog leg," like Fig. 185, to accommodate the pins. For 4 plates a lever and roller to match may be bought, and the position of the pallet holes arranged to suit them ; or they may be made as before described. The arrangement of such a conversion is like Fig. 186, the dotted circle showing the old scape wheel.

In converting chronometers, duplex and cylinder watches, new fourth wheels, where required, and new scape pinions may be of the same numbers as before. Then the hairsprings will be used again, together with the balances, just as they are. But if such a watch has a plain balance, it will be much the best to put on a new compensation balance, if there is room for it. In this case it will need re-springing as well.

Converting Verges.—Verge conversions are rather more trouble. Some verge trains are so arranged that the third pinion can be left alone and the escapement planted quite free of it. But the ]majority require a platform made to go over the third wheel, like a bridge, and carry the escapement. The third pinion then must be cut down very short and its top pivot run in the bridge. The fourth pinion comes through a hole in it. The arrangement is shown in Fig. 187. The old potance can be generally filed and turned out to take the roller and allow the lever to reach it. If not, and a new potance has to be made, the entire escapement may as well be included in it, and the top third pivot run in its under side, as in Fig. 188 ; or the bridge shown in Fig. 187 may be extended to take the lower balance pivot as well. In converting a verge, a new fourth wheel and scape pinion will have to be supplied, and the numbers must be such as to make the train as near to 16,200 as possible. They can be calculated according to the directions given on p. 133.

An old "club roller" or "rack lever" is easily converted by supplying a new wheel and pallets, and lever and roller, and re pitching the depth.

Keyless Conversions.—A really good f plate key-wind fusee English lever is sometimes worth converting into a key-less. The best job is made by dispensing with the fusee and fitting a going barrel, with a new top plate, fitting ordinary rocking-bar keyless work and new motion work. The movement, if sent to a movement maker, will be fitted with top plate, new barrel, and keyless work all in the rough. It will then all require finishing as in a new watch. It will want " boxing in " to the case and a new case pendant. The case-maker will do this, part. He will fill in the keyholes also.

Improving Watches.—A good watch with compensation balance and a flat spring may often with advantage be altered to a breguet. Occasionally the same balance cock will do again, but generally it will be best to make a new one and stud it on the left, fitting a proper index. The old spring, if a good one, may be turned up into a breguet, or a new best hardened and tempered one put on.

Many a good 3/4 plate English lever may be much improved and made to look many years newer by a small outlay. Top plates of the shape shown in Fig. 189 may be filed up to a nice curve, as shown by the dotted line, and a balance cock like Fig. 190, A, may be turned like B. Plates may be stoned smooth and free from scratches, and the frame re-gilt. The squares, index, etc., can be re-polished and the screws re-blued. Scratchy blue screws may be re-blued without polishing, as may hands and other blue steel parts that have partially worn bright. Brush them clean and free from finger marks, and place on the blueing slip until the blue reappears all over.

The tops of brass jewel settings get shabby, or after stoning and gilding a plate, stand up too high. In such cases stone them smooth and level as they lie in the plate, then remove and polish them upon a pewter polishing block that has been filed flat. Apply red-stuff and oil and insert a peg point in the jewel hole to rub them over the block with circular strokes.

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