Any tips to correct a sloppy error?

[Geotex]

It's probably a cardinal rule for watch repair to never get distracted while at the bench. Yesterday, after finishing a tricky mainspring winding/barrel insertion (I didn't have a winder and arbor that fit very well) I mentally shifted down a gear once that hurdle was passed. There were other things going on in the room as I put the barrel and cover into the barrel closer and pressed to get that satisfying snap. But when I took it out I realized I never placed the arbor. 

When opening a barrel, we are relying on the arbor to transfer a concentrically-distributed force right where it is needed at the internal center of the lid. However, when that isn't present it's difficult to apply pressure or get leverage considering the recessed position of the lid, the small holes in the barrel and the presence of the mainspring coils.

It was a beat-up practice movement so I didn't take a lot of time to think it over and I pushed it out using a short right-angle dental probe placed in from the bottom, but that did leave a bit of a scratch and crease in the thin lid. I had also thought about pulling it using a course-threaded screw with a minor thread diameter smaller than the lid hole and a major diameter larger, but that may have done some damage as well. 

Thinking about how this might have been handled had it been a more valuable movement, is there a method using watchmaking or other tools that should extract the lid with the least damage? 

[RichardHarris123]

Glue a nut to the barrel lid, insert a bolt, pull, disolve the glue.  Maybe someone will have a better answer. 

[Geotex]

That's a good idea - shrinking down the nut and wrench size from the old casebook trick!

[rjenkinsgb]

Two pins or screwdrivers angled out slightly, pressing through from the barrel centre from the opposite side so they contact just clear of the hole in the lid?

eg. Strap pin driver needles or similar.

[Geotex]

That could work - two blunt pressure points would spread out the force required in order to reduce damage, and two small pins should fit slightly angled through the inner coil of the spring. 

I was thinking about this while working on other chores and had a crazy thought when I saw a can of expanding rigid sprayable foam, but who'd want to have to clean out the barrel and spring after that?

[HectorLooi]

This happened to me several years ago when I first got my barrel closing tool. In my eagerness to try out my new tool, I closed the cap without the arbor.

I don't quite remember how I opened it. I might have used compressed air to pop the cap off. I sometimes use compressed air to open those "sealed" Seiko barrels.

Edited April 26 by HectorLooi
Typo

[Neverenoughwatches]

23 hours ago, Geotex said:

That could work - two blunt pressure points would spread out the force required in order to reduce damage, and two small pins should fit slightly angled through the inner coil of the spring. 

I was thinking about this while working on other chores and had a crazy thought when I saw a can of expanding rigid sprayable foam, but who'd want to have to clean out the barrel and spring after that?

I've used expanding foam for lots of things but i thinķ you got me on that one. 

[Neverenoughwatches]

On 4/26/2024 at 12:26 AM, Geotex said:

That could work - two blunt pressure points would spread out the force required in order to reduce damage, and two small pins should fit slightly angled through the inner coil of the spring. 

I was thinking about this while working on other chores and had a crazy thought when I saw a can of expanding rigid sprayable foam, but who'd want to have to clean out the barrel and spring after that?

I think attaching a nut to the lid to pull it off is the least destructive, any damage damage on the outside is going to an easier fix than any created when trying to push it out from the inside. Scratching up the inside of the lid , mainspring or arbor bearing will be risk. Just my opinion.

[Geotex]

Thanks for the feedback. Hopefully it won't happen again, but you never know.