This jig is used to mark out for crossing out clock wheels to form the ‘spokes’. I had previously done this on a milling machine and it is no coincidence that the two clockmakers that saw my wheels commented on the lack of taper on the spoke. There are a variety of plans available for this type of jig.
I used a scrap piece of brass plate that had been heavily scribed on one face but had a clean upper face. The brass is approximately 1/8″ thick. It was roughed to size with a piercing saw and then screwed to an aluminium back plate in what will turn into the centre holes and the four holes in the first circumference.
Ok, a little more done and this should show how it works. It’s nothing mind blowing, just a simple jig to quickly cross out wheels.
So I’ve turned up a few stubs and pins but I need to turn up more, the idea is you build up a collection as time goes by so it isn’t something you need to keep doing.
The wheel is mounted on a central stub that is tight fitting:
There is a tiny centre pop in the centre stub to mark out the inner centre and outer rim:
Then if you want 1/8″ spokes, you machine up two 1/8 pins, put them in the appropriate dividing holes and mark up.
This can easily be done marking out in other ways but it’s fast and I hope to maintain an interest in clocks, it should be a useful tool. The real benefit is that using different size pins, you can achieve taper on the spokes… More pics to follow.,,
Hi Chris,
I’ve learned a lot from you in connection with gear cutting etc for which many thanks.
However I thought the following would be of interest.In his book Watchmaking, page 123, George Daniels says the following:
Wheel Cutting, preparing the blanks.
The wheels should be crossed out BEFORE the teeth are cut to avoid possible distortion of the rim. The crossings need not be finished but the bulk of unwanted metal should be removed.
I think you’re doing it the other way round. Any reason for that?