Titanium Balance

I was invited to this group, though I’m more of a “some dude who tinkers” than a watchmaker. Regardless, I appreciate the welcome, and I thought I’d share my balance wheel progress as my intro post

I am very open to critique and ideas, especially due to the unique nature of this part.

Since I assume this group is full of more experienced watchmakers than the other group, I’ll be more concise with my overview.

To start, I turn a blank out of grade 5 titanium on my big shop lathe. It has a specific shape to allow me to drill my pilot and weight holes on my Bergeon lathe.

Next, it’s hours and hours of filing. I’m sure with a proper mill, like an aciera or something, I could cross the wheel out easier. But I have a cheap, “King” mill, and it does not have the precision required.

After hours of filing, and making sure the spokes are even, I do a poise test to see if I’m especially off.

After that, I shaped the spokes to be more aesthetic. The heart of the watch is this wheel, and it always stands out to me when the wheel is beautiful, not just functional.

The wheel is shaped with half a dozen files, ranging from barret to half-round to balance, from cuts 4 to 10. Ruby stones are used after the cut 10 files, and then finally it is polished with oilstone paste and Diamantine. After finishing the spoke polishing, I add a brushed finish to the faces.

Bear in mind, it is not complete yet.

For the weights, I wanted to maximize mass to take advantage of the lower mass of titanium to create a high moment of inertia.

The weights are platinum, and are made so the weights themselves press into the balance. They are then sandwiched from the back by steel posts. The post in the photo is a test, and the final posts will have a thinner backing.

FAQ:

Q: Why titanium? A: It has a lower CTE than Glucydur, and its antimagnetic compared to invar. Its low mass allows for a high moment of inertia. It also looks cool when you anodize it.

Q: what about the hairspring? A: I dunno. I’ll try making one out of a titanium alloy, but failing that I’ll use Novarox or something. I spoke with an engineer friend of mine, and he said that doing the math for the hairspring would be an undertaking akin to his thesis. So trial and error with a vibrating tool will suffice.

Q: what about poising? A: I get it as close as I can, then add the weights, then adjust the steel posts and wheel spokes for perfect poise.