This week I am attending the Lathe 1 class at the AWCI. Most of the first day was learning how to sharpen gravers correctly, lathe maintenance and set up, as well as learning how to make cuts.




long curly pieces are a sign of good cutting.

It’s easy to cut off material. Much harder to keep things parallel and not have a taper or unevenness. This was to practice making something within the specifications and tolerances from a drawing. We will be moving on to making actual useful things later this week.

 

Have fun sawing your square!

 

That’s tomorrow, the balance tack project. We made a watchmakers pick today. I’m getting decent turning brass on the lathe. Filing a brass cylinder into a tapered screwdriver like point was harder than I expected. My only real file experience is dressing screwdriver blades. With those, you have pre-existing profile to follow.

 

The balance rack project is well under way. The “tack” part started as a ~4.8mm brass rod. I first cut the bottom end to size and threaded it. I didn’t get any pictures of that process. The marked area is where I need to turn the center section down to 4mm:

Next the piece is removed and new collect is selected so it can be chucked up on the just finished 4mm section so that the other side can be worked on:
Initial taper of the point is cut:

And finally the finished item:


All told it took me about 6 hours to do this. Even though it is a tool, we had to keep all the dimensions at +\- .05 mm, I kept it at +\- .03 mm. A sheet of paper is .08mm. If you are making a watch part, the precision must be even higher.

 

Project complete:

We made the pilgrimage to the nearest Goldstar today.

 

Today was cutting a staff out of a balance. There are other ways like using alum powder dissolved in water. It’s good to have multiple ways to do things.
You come in from hub side not the rivet side with a carbide graver. Your goal is to not touch the balance wheel with the graver, only the staff, the angling of the graver properly achieves this.

With a Glucydor balance, cutting the staff out isn’t necessary, a Horia tool can be used to push the staff out by breaking the rivet. Glucydor balances are hard enough they won’t distort during that operation. Rolex has a special stump and pusher for the Horia tool for this operation. Making some will be one of my first lathe projects back in my home workshop.

 

Even if the actual rivet breaks off cleanly, there is still an enlarged part of the staff that is forced through the hole in the balance. As you say the arms of the balance aren't going to get distorted, but the hole will be enlarged in the balance. I know Tom teaches that it's okay to do this, and Rolex does it*, but it's just not something I will do personally.

I will always cut the staff out in the case of a steel or bi-metallic balance, but for anything else I'll use alum. I've detailed the process here, and not only is this completely risk free, the balance can be soaking in alum while I'm doing some other task, so it's very efficient.

https://omegaforums.net/threads/basic-watchmaking-tips-replacing-a-balance-staff.96778/

So if you choose to do it this way that's up to yuou, but there are better ways of removing a staff that don't put the balance at any risk at all.

Cheers, Al

* - note that one some newer Rolex calibers, they are going back to the old Waltham style friction fit balance staffs, so no riveting of staffs,. and no punching out of staff required. To me this indicates that Rolex is not as "okay" with punching out staffs as some believe.

 

I'm with you on the alum, I used it to remove a broken stem pilot form a main plate after I removed all the other steel parts from it. It worked well. During the CW21 exam, there won't be time to use the alum method however. The Rolex 32xx is a friction staff. I'm pretty Rolex is ok with pressing the staff out, I saw the actual Rolex Horia pushers/stumps. If there is one thing Tom knows very well, it's how Rolex does things, good, bad or otherwise.

 

Well, unless the exam has changed a great deal recently, you won't be able to punch the staff out either. You will have to cut it out on the lathe.

Yes he does. However my point is I would be cautious using the logic that because Rolex does it, it's okay to do. I'm not sure how many balance staffs you have changed, but as I've explained there is an enlarged portion of the staff that will be pushed through the hole when you punch it out - that can't be avoided. It may not be an issue the first time a staff is replaced on a Glucydur wheel, but the 5th time you will end up with a hole that is oversized, and will have to spread the rivet even wider while trying to keep everything centered. Rolex doesn't care about the 5th time...they care about getting the job done quickly in their service centers.

Trust me that once you get out and start doing this a lot, you will see the drawbacks of methods like these first hand. Just like any schooling this gives you the basics, and the real education begins when you start doing the work out in the world.

Tom is a great instructor that I have a lot of respect for. He always reinforced the drive for excellence, which is part of what has made me the watchmaker I am today. But by the same token you need to have an open mind and consider alternate ways of doing things that might be even better. Watchmaking education is very dogmatic, so don't get blinded by that - think things through for yourself...

Cheers, Al

 

Pretty cool. I’ve not used a Lathe since I worked summers in a university physics department shop as a teen.