Mechanical WW How do I open this mainspring barrel?

[Charlie Ryan]

This is a chinese 6497 I bought for learning the basics. I want to remove and reinstall the mainspring but I can't figure how to open the barrel. Any ideas?

Thank you

 

[Chris Radek]

Put it cover-up like in the second picture on your bench anvil, and press down on the teeth with your thumbnails. The arbor will easily pop the cover out.

 

[Charlie Ryan]

That worked. Thank you cradek.

 

[wrobbie]

I have the same Chinese movement, which cost ~$30 brand new. Be careful with the bridle at the end of the spring. Mine came off because it was poorly welded, and I had to buy a new spring ($12, ugh).

Besides that, the ratchet teeth on the winding and sliding pinions are poorly cut, and winding is nearly impossible without skipping. New parts would be another $30 or so. No thanks

Timekeeping is surprisingly good, and regulation is a breeze.

 

[Charlie Ryan]

Thank you wrobbie. I’ve also noticed the issues you describe. Though good practice pieces for us ham fisted learners.

 

[Al J]

Put it cover-up like in the second picture on your bench anvil, and press down on the teeth with your thumbnails. The arbor will easily pop the cover out.

Certainly opening a barrel this way works, but please remember that it often distorts the lid of the barrel, so you need to check the barrel arbor end shake and adjust as required.

An alternative to the method described is to use canned air to open barrels - you just need to be able to fit the end of the tube over the barrel arbor, then give the trigger on the can a quick squeeze, and the barrel will pop open:



This works on barrels that don't have holes in them obviously, and the even pressure that the air applies to the lid tends to keep the shape of lid rather than create a cone shape that the method pf pressing the arbor on the bench will create. Doesn't work for all barrels, but whenever I can this is the method I use.

Cheers, Al​

 

[Chris Radek]

I knew someone would have a better way, and I'm glad that it isn't some special-purpose Bergeon tool for $2000. Thanks for sharing this, I might try it! Your canned air might work for front-loading cases too...?

 

[Al J]

I knew someone would have a better way, and I'm glad that it isn't some special-purpose Bergeon tool for $2000. Thanks for sharing this, I might try it! Your canned air might work for front-loading cases too...?

It would likely pop the crystal out, but since these cans of air have a fair bit of pressure I would be a little concerned that the rush of air exiting the case after the crystal pops might cause some issues...maybe with the balance spring...

I don't open these cases that way, and typically I use specific tools that the brands used to sell for the watches that I have gathered over the years.

I've seen videos of people using a large syringe to generate pressure to pop a crystal, and I think that would be safer than canned air.

Cheers, Al

 

[Charlie Ryan]

Certainly opening a barrel this way works, but please remember that it often distorts the lid of the barrel, so you need to check the barrel arbor end shake and adjust as required.

An alternative to the method described is to use canned air to open barrels - you just need to be able to fit the end of the tube over the barrel arbor, then give the trigger on the can a quick squeeze, and the barrel will pop open:

View attachment 462431

This works on barrels that don't have holes in them obviously, and the even pressure that the air applies to the lid tends to keep the shape of lid rather than create a cone shape that the method pf pressing the arbor on the bench will create. Doesn't work for all barrels, but whenever I can this is the method I use.

Cheers, Al​

Also Very clever indeed! Thank you.