2024-01-14

Last modified: 2024-01-14 16:20:52

Duplex escapement model

The plan is to work out exactly what is wrong with the balance shaft, or plates, and fix it so that there is clearance for the hairspring collet.

I'd also like to glue the balance cock to a superglue arbor and face off the top of it, because I did not do a satisfactory job with hand files.

The gap between the bottom of the balance wheel and the top of the mainplate is about 3.65mm. In CAD it is 3.5mm, so not actually a million miles away.

I've depened the lower cone pivot slightly, using the chamfer tool by hand, not sure I've done any good though. It seems to not be sharp enough for this application, the flat on the end of the tool is about 0.6mm across, which means my 0.3mm centre is effectively drilled in a flat surface instead of a cone!

Anyway, next up let's try to tidy up the balance cock, then cut the rollers on the balance shaft, and maybe shorten the adjustable pivot and the balance cock screws. And tidy up later because it is getting messy in here again.

Fitting on the superglue arbor:

Much better:

I think part of the problem with the upper pivot is just that the cone in the screw is too deep, so I'm going to face some of the cone off, then shorten the screw and cut a slot in it.

Well it's a bit shorter, and I shortened the cone:

But it still looks like the hairspring collet is bearing against the flat surface, instead of the point bearing in the cone. And the slot in the screw is bad because I cut it with the angle grinder. And obviously the screw is still way too long.

But let's move on, I need to cut the rollers on the balance shaft and then I can Loctite the balance wheel in place.

I think try to use the 3mm collet to clamp on the 2.4mm diameter. The other option is to make a 2.4mm or 1.6mm hole and try to superglue the shaft into it? I think the collet will work better.

Well it's clamped:

The paper is there to provide some clearance from the face of the collet, although I worry I will hit the collet anyway.

Ugh, I dropped a 1mm end mill on the floor and broke it. Great work jes.

After the first pass:

I think this is good, just obviously not deep enough.

Great success!

This looks like it might work, although the scale may be too small for my achievable precision in positioning the parts. The locking roller is probably too small.

I'm going to try to Loctite the balance wheel on and then stop for a bit. But how to get it on square? Maybe just wing it for now.

Well it looks OK for now...

I've drilled a hole for the hairspring, and fitted it with a tapered pin:

The spring is rubbing on the balance wheel. I think the problem is that the hole is drilled too "high" in the balance cock, which means the spring has to bend upwards to reach the hole, which means the opposite side bends downwards and rubs the wheel. In principle I could bend the spring to straighten it out, but I think for now I'll just leave it alone and proceed.

https://www.youtube.com/watch?v=66XZLGQiUcs

Next step: escape wheel.