Week 4 Aug. 16-21, 2010

Hello again. Here we go with week 4. Nice to know that some people are actually following this blog now. It makes posting new things feel a little more useful.

Anyways...

This week I started with turning the holes in the new bridges to 0.01mm smaller than the jewels. I did this by first centering the jewel I was working with on the M1. We have an attachment for it now that can be moved to the Schaublin lathe which makes things much easier. So after I had the jewel in the mainplate centered, I screwed the bridge onto the mainplate and turned the hole to the correct dimensions. It wasn't extremely difficult, but you have to be very precise. If the hole is too big the jewel will be too loose in the hole, and if the hole is too small the jewel can crack. I don't have any pictures but they would be pointless anyway, just jewels fit into the bridge. I'm sure you will see it in another photo later.

So then I set out making a new pallet fork bridge. The original one is quite ugly and had to be redesigned. I also decided to make locating pins on the bridge instead of on the mainplate like the original. I don't like the idea of being able to see locating pins.

It wasn't really easy designing something that went with the other bridges. The first design I came up with was kinda unique...

But there were some issues with this design. First of all it would've been extremely hard to bevel and polish. And secondly, when I put the balance bridge on it covered up the 'flames' or whatever you want to call them. So I just simplified it to this design:

So after making the shape how I wanted and screwing it on the plate, I had to turn the hole for the jewel like the other bridges. Unfortunately for me it was Monday and not my day. I had pre-drilled the hole for the jewel, but I wasn't thinking and drilled it too close to the final diameter. So when I went to center it on the bottom jewel it was way off. Like wayyyy off. So i had to make another bridge and pins. One of these days I'll start thinking things through better before proceeding. But for now I'll blame it on Monday.

Also because the bridge is in steel, the fit of the jewel has to be much more precise. Thankfully the school has many pivot gauges to help measure everything to pretty precise dimensions. The jewel fit great.

The next thing on the agenda was getting a nice new mainplate to do some actual official work. All of the other work on the mainplate is for trials and stuff. But now I have the actual mainplate so I need to be careful with it. The first thing to do was to plug all of the useless holes. Because I changed the design of the bridges, the screws and locating pins are all in different places so I needed to fill a lot of holes and also drill new ones. One other thing I wanted to do was get rid of the dial feet securing pins. The look horribly ugly and just not acceptable on my watch! I am planning on making a tapped hole from the side and a screw to hold the dial feet. And I will put it under a bridge so you can't see it.

So after drilling many new holes and plugging old ones, here is the result. There is still 4-5 holes that might get plugged, but I was not sure about them yet so I left them. Maybe I'll put a side by side picture of the new plate and the original to show how many holes are gone...

I also milled off the left part of the old pallet fork bridge, and milled off the part that said ETA 6498-1. Can't have that on my watch! Maybe I'll put AMS-01 on it haha....

Next thing I did was make the bronze bearings for the barrel arbor. The original design doesn't allow for any adjustment of endshakes. And if you went to school at WOSTEP you know that is just not acceptable. And the reason I am using bronze instead of jewels is because this is a lager watch with a big heavy barrel. So using bronze is just a bit more sturdy.

Parting off the bearing on the lathe

A pretty easy and quick process on the lathe. I will still have to turn the holes in the mainplate and bridge to fit the new larger bearings.

The last thing I worked on this week was banking pins. If you are like "Aaron, WTF are banking pins?" then I suggest you click this link. It is a Swiss lever escapement in motion. I hope you are able to see the two pins that the pallet fork rests on.

Since got rid of the old pallet fork bridge that had the banking pins on it, I have to make new ones. The are a munch of different types. I am trying to make eccentric screws for mine. They are only seen in high end watches. And after trying to make a couple I can see why. They are probably one of the smallest parts I will have to make and, although not overly complicated, very tough to make precise. The first one I made didn't quite work out but I think I have the process figured out so hopefully it goes well next time.

The other thing is that the head of the eccentric screw will be flat polished so I can only really do this at the very end and after most of the watch is already finished. So it might be an interesting journey to get these things to a) function properly, and b) not leave a mark on them before I put the watch in the case at the very end. Hmmm...

Just a pic of the screw head cutting.

And this is the tempering.

That's all for now. Not sure what the plan this week is. Might try to do some actual school work. But this stuff is quite enjoyable so we'll see...