GENTS PULSYNETIC WAITING TRAIN FOR ELECTRIC MASTER CLOCK TURRET | eBay
Without it no clock dial, hand drive is possible. Though this will not affect the ability of the heavy pendulum to swing under power, is is very likely the ratchet wheel will spin around uselessly during part of the cycle.
An optimistic idealist might also have hoped for a bevel wheel cluster and crown wheel but there would be little point without a wormwheel to drive them. Since no known spares are available for these old movements it falls to the new owner to arrange the manufacture of a wormwheel and shaft. A second, cast support bracket, for the worm shaft is also missing and would need to be reproduced. Forked expansion [universal] joints for the lead off work would be desirable if a hand drive is needed for a clock dial. These are more readily made from channel section. Or can sometimes be found on eBay since they are almost universal in turret clock lead-off work to the dials.
There is a way to manufacture a wormwheel in aluminium by "hobbing" with a screw thread cutting tap in a lathe. Whether there is a screw thread which exactly matches the W's worm in all respects I really cannot say. Interestingly, the aluminium would not look too out of place. Bare, lightly brushed aluminium is not too dissimilar to the WT's original, matt plated components.
The original wormwheel would be a spoked casting in bronze. Perhaps a machining enthusiast can be found who would make a new wormwheel out of brass using a dividing head and hand-made, fly cutter. This would be much more difficult and require more equipment and skill than hobbing softer aluminium with a matching screw tap. [If one was available!] There is just a chance that Gents chose a standard thread for their WT worm so that it could be easily cut on a normal, screw-cutting lathe. So using a non-standard screw thread seems less likely. Gents were mechanical, turret clock makers so would have no problem producing wormwheels.
The original time setting crank is present on this WT. As is the Hipp toggle damper with dangling rubber hose. This has the effect of stopping the Hipp toggle from vibrating so wildly that it might seat in the Hipp V-block on the return swing. This would result in power being sent to the pendulum drive in opposition to its swing. Resulting in a stalled pendulum with the power running continuously through the contacts and drive electromagnets!
This is an unlikely, but not impossible, occurrence and rather depends on the lateral and vertical adjustment of the pendulum drive contacts. The simple toggle damper provides a high level of insurance against this happening. I ran my own similar WT without a damper for years without any problem during normal running. Only during manual contact adjustment was there ever a problem with the toggle rocking back and forth deep in the V-block.
The original, ceramic knob on the time setting crank is a nice detail. For some reason these hand cranks often go missing. This crank allows the time on the [missing] time setting dial to be quickly corrected for Summer and Winter time setting of the driven clock dial. Or the hands to be quickly set to time after a pause for maintenance. The time setting dial would be mounted on one of the bevel wheels and fitted with a small pointer This was standard turret clock practice though njhand cranks would serve no purpose .
This drive system can be most easily recognized as an inverted roller and pallet common to the gravity arm impulse of popular British master clocks like the Gents' Pulsynetic. The drive action can be repeated on demand from the Hipp amplitude switch up to 30 times normal during bad weather. Or when ice, birds or wind impede the hand movement on the exposed clock dial[s].
The only way to repair such a disaster could be to to unwind the entire coil to reach the broken wire. It goes without saying that such an event would destroy all originality in appearance of the affected coil. My own advice would be to leave the electromagnets in situ and wrap the coils with cling film[?] to protect them from gentle cleansing of the metalwork. I used odour free lamp oil to clean my own WT as a gentle solvent. [GB paraffin. US Kerosene?] A "factory gate finish" is highly undesirable IMPO. The patina of age on the movement is part of its history. It should be respected as much as possible.
The pitch of the worm and its diameter do not seem typical of imperial threads. Though worms do often use an ACME thread form. The worm is 5/8 [0.625"ø] and has 13 threads in 7/8" [22mm] Converting to the full inch makes 14.8 TPI. Perhaps it is a Metric thread? 1.69mm pitch?
The bevel wheel shown on the right is not always a standard feature on all WTs. The hands of a single dial may be driven straight off the wormwheel shaft via a universal, lead-off, expansion joint. Which is the plated forked device seen on the far end of the shaft.
Two dials in line on opposite ends of the WT movement may be driven by having another universal joint on the other end of the wormwheel shaft. Bevel gears are only necessary where there is a change of height or direction between the movement and dials. Or where three or four dials are driven from one movement. Or where two or more dials are at right angle to each other on a tower or building. WTs are incredibly powerful for their size and even this smaller C40A can drive the hands of four 6' dials.