Closing mainplate pivot hole for barrel when hole is tapered

[ManSkirtBrew]

Starting to assemble this Seiko 6139 and the pivot hole in the mainplate has more wear than I'd like. It's not terrible, but it's definitely oval and you can see wear on the plate from the barrel rubbing.

I know jeweling kits are available, but they require reaming the hole precisely, and I was hoping I could shrink the hole with my staking set and broaches instead of adding to my pile of single-use tools I've purchased for various projects.

However it looks like I can't due to the way the hole is countersunk on the bottom. Just thought I'd ask you more experienced folk before giving up.

[Neverenoughwatches]

15 hours ago, ManSkirtBrew said:

Starting to assemble this Seiko 6139 and the pivot hole in the mainplate has more wear than I'd like. It's not terrible, but it's definitely oval and you can see wear on the plate from the barrel rubbing.

I know jeweling kits are available, but they require reaming the hole precisely, and I was hoping I could shrink the hole with my staking set and broaches instead of adding to my pile of single-use tools I've purchased for various projects.

However it looks like I can't due to the way the hole is countersunk on the bottom. Just thought I'd ask you more experienced folk before giving up.

You can still peen the arbor hole from the inside where the barrel sits. The outside seems like a deep oil sink or has been previously peened because of wear. Find a round nose stake to match what is already there.

[ManSkirtBrew]

7 hours ago, Neverenoughwatches said:

You can still peen the arbor hole from the inside where the barrel sits.

This is exactly what I was wondering, thank you. Having never done it before, I wasn't sure if it was okay to just peen it from one side.

Although in fairness, if the only other option is reaming and jeweling, there's no harm in trying, right?

[Neverenoughwatches]

38 minutes ago, ManSkirtBrew said:

This is exactly what I was wondering, thank you. Having never done it before, I wasn't sure if it was okay to just peen it from one side.

Although in fairness, if the only other option is reaming and jeweling, there's no harm in trying, right?

I haven’t  done loads of that kind of work, ideally close from both sides but if you're not comfortable with closing the outside it should still work. Tbh i would say only a temporary solution even more temporary if the watch is worn daily. The thickness of the bearing material is going to be much less than it was when it left the factory so its going to wear quicker that it did originally. 

[ManSkirtBrew]

5 minutes ago, Neverenoughwatches said:

The thickness of the bearing material is going to be much less than it was when it left the factory so its going to wear quicker that it did originally. 

This was also my thought, especially on a high-pressure pivot like the barrel.

Thing is, I don't have a Seitz style jeweling press, nor reamers. I've been searching for reamers that would fit my staking set, but no luck.

I have been wanting a lathe, though...

[Neverenoughwatches]

43 minutes ago, ManSkirtBrew said:

This was also my thought, especially on a high-pressure pivot like the barrel.

Thing is, I don't have a Seitz style jeweling press, nor reamers. I've been searching for reamers that would fit my staking set, but no luck.

I have been wanting a lathe, though...

Get both .

[nickelsilver]

If using a round punch on the barrel side, you have to be really careful not to make a dome larger than the shoulder of the pivot. The shoulder will go into the dome, increasing endshake and massively increasing friction. I won't say I never close holes with punches, but I've found it's quite hard to do it and have a really good result. The hole will close, but not be cylindrical anymore. So you broach it a bit, which still isn't cylindrical but an improvement, but now maybe  the hole is as big as it was to begin with, and back and forth you go. If you close it just enough that the slop is taken up, the fact that it's small in a small portion of the hole length means it will wear quickly back to where it was. I have the view it's kind of like putting sawdust or bananas in a noisy car transmission, helps for a while, but not very good long term (I know I just dated myself there).

[ManSkirtBrew]

Thanks for the advice, all. I just found a reamer holder for my staking set, and purchased it with a bunch of reamers from Dave's watch parts.

Might as well do it right.