Seitz jeweling tool .

[rogart63]

I was happy to find a nice one here recently. Have tried to ream out a barrel hole on a 6217 but it got wrong. The reamer slide away and did a hole a little to much to the left. So that ended up in the scrap. I don't now how to avoid that? Should need have something to hold the movement plate in place with. But what? Is  there such a tool? Hold it for free is hard. something like the one with 3 arms on . 

Edited July 26, 2017 by rogart63

[Marc]

I know that some of the Favorite jewelling presses were supplied with an uprighting attachment which was basically a plate which could be rigidly bolted to the base of the press on which there were 2 or 3 clamps. This allowed you to accurately position the work piece where you wanted it and then clamp it securely in position before reaming out the hole. This would be very useful if you were making replacement bridges or plates from scratch or rebushing no jewelled bearings. I don't know if Seitz did anything similar but I wouldn't be surprised if they did.

Then there are dedicated uprighting tools which do the same job.

However, although you could use an uprighting set up to ream out the barrel hole my preferred option would be to use the lathe for this job, mounting the barrel in a stepped collet and using a graver to recentre and size the hole to receive the new bush.

Obviously if you don't have access to a lathe then an uprighting set up is your next best option. After that it may be possible to broach out the hole by hand using the same approach that is sometimes advocated for rebushing clock plates. My understanding of this process is that the hole is usually only worn on one side, elongating it in that direction. The process involves using a file to elongate the hole in the opposite direction until it is symetrical with its true centre where it should be. You can then ream or broach the hole by hand as the tool will naturally stay on centre. I believe this is because the cutting edge of a broach or reamer is along it's side and the tool is naturally pushed to the path of least resistance which is cetrally in a symetrical but out of round hole, unlike a drill which cuts at it's tip and therefore makes it's own centre. I would think that the hole in the barrel is probably large enough to adopt this approach.

I hasten to add that I haven't tried this approach myself and may have it completely wrong. It would be interesting to hear CB's  or Old Hippy's views as they have vastly more experience with clocks and will be in a much better position to advise wether such an approach could be used for a watch barrel.

[rogart63]

The movement i am having trouble with is a seiko 6117. It 2 different thicknesses . And as Marc says it's worn more in one direction. I have a jewel to replace the worn hole. 

[Marc]

Ah.. I misunderstood. I thought that you meant you were re-bushing the arbor pivot hole in the barrel. It looks like you were doing the pivot hole in the main plate which makes the step collet in a lathe approach wrong. It can be done on a lathe but you would need a face plate with clamps to get the axis of the hole true to the spindle.

The broaching or reaming by hand method would also be a bad idea as the different thicknesses of the plate around the hole would result in the broach finding a totally different centre due to following the path of least resistance.

Your best bet for this job is an uprighting set up which works best if only the hole in the main plate is worn and the hole in the bridge is still good. What you do is you bolt the bridge (with the good pivot hole) into place on the main plate and then clamp the main plate to the table of the uprighting tool using the hole in the bridge to align the plate with the axis of the uprighting tool. Once securely clamped in position you remove the bridge from the main plate and ream out the hole knowing that it is centred true to pivot hole in the bridge and that when finally assembled the pivot will be upright between the plate and the bridge.

I believe that Mark did a video where he replaced a worn centre wheel bush with a jewel which demonstrates the process.