Week 2 August 2-7, 2010

This last week I started working on the bridges for the watch. I designed 3 bridges of which I will make from scratch. Hopefully I will use the stock barrel bridge but not quite sure about the balance bridge. I think I will end up making a new one since the stock one is a bit lower than the other bridges and probably won't work out, but I'll deal with that later.

First thing I did was mill out the new shape for the barrel bridge. This wasn't very difficult or time consuming. I just found the correct radius and milled it on the M1.

The next bridge I decided to do was the 3rd and center wheel bridge. It is the biggest so I thought it would be good to get out of the way first. I spent the first day trying to figure out how to actually go about making it. I ended up having to plug 2 holes on the mainplate so that I could make new ones in the spots I wanted. after that I glued a flattened piece of brass onto the mainplate and located where I needed to put the new screw holes and locating pins. Then I drilled the holes and tapped the screw holes.

Here you can see the rough piece after the screw head sink holes were done. The bridge is still way too high but this allows lots of room for milling the rough shape on top.

Now that I had the 2 screw holes in the correct spots, I could just screw the bridge on to do the rough milling. I didn't put the locating pins in at this point because this bridge had two screws and didn't need them.

Here I am just milling out one of the sides on the M1. Because of the shape of the bridge I couldn't mill everything out on here so I had to mill a rough image of the final dimensions. This made it much easier to file the rest of the bridge out by hand.

Here is the bridge design I made. I think it looks pretty cool! Just for a reference, this is the original bridge design so you can see how much different it will be. You can see I only milled the two right hand edges. The rest I just milled on top so I would have a guide for filing. The reason I didn't mill it out was cause the milling cutter likes to catch sometimes if you don't control it properly and I didn't want to risk it slipping and ruining the whole bridge.

I had also milled the shape for the balance bridge (even if I don't use it). It was a quick job so not a big deal.

Above is the start of the filing process. Had to do a LOT of filing! I basically spent all of Friday (about 7 hours) filing this part to the shape I designed. Filing isn't the most fun activity but it's nice to see something actually taking shape!

So after many hours of filing I was pretty close. The dimensions aren't exact or anything yet. After that I milled the top down to about the same height as the original bridges. I still have to mill out the recesses for the wheels underneath. Then after that I will have to make the holes for the jewels.

Here is the piece being milled on the top:

After getting the top milled out I made some pins out of german silver to push into the underside of the bridge for locating pins. These pins and their location are very important because it will ensure the bridge is always screwed down to the same position every time. This maybe has more importance on a bridge with only 1 screw, but it still makes a difference on any bridge. So after all of that, here is the bridge on the mainplate with the other 2 bridges I finished, looks pretty good so far I think!

And this is the cluster-cuss that is my bench when working on this project! Not easy to keep clean when you are using so many tools at once....

See ya next week!