Removing Barrel Cap

[NewBernWatchmaker]

I read "lift open with screwdriver" but I can not get a screwdriver to get between the spring and cap and when it slips it scratches the cap. Anyone have a trick?

 

[Chris Radek]

Check out this thread:

Mechanical WW - How do I open this mainspring barrel?

 

[DeweyC]

Yes. The method we were taught in Switz. was to press the cap off using the arbor. There are some barrels with no slot, just a lip and some barrels (37500) are a very tight fit. For the 37500 and the Lecoultre, I made a Delrin die that the barrel fits into nicely and it rests on the teeth. Then I press out the cover/arbor with a press. If you do a lot of pocket watches it may be worthwhile to adapt this to PW barrels.

I use a Delin stake to replace the covers (Bergeon sells this for about $40, a Delrin slug is like 50 cents).

 

[karlmansson]

Check out this thread:

Mechanical WW - How do I open this mainspring barrel?

Yeah, the screwdriver method only works with lids that have a slot or half hole in them. I use the finger nail method most of the time, even if a lid has a slot in it. If the lid gets deformed, at least it gets deformed uniformly as opposed to a lid bent by a screwdriver. If I need to correct it I’ll use my Favorite jewelling tool with a large diameter hollow stump and push in the middle to take out the “bowl” from the lid.

 

[NewBernWatchmaker]

Thanks guys I would have never thought to put force on the arbor but it makes sense, doesn't scratch the cap or barrel, and the cap is easy to straighten if it does become distorted. Thumbs up all around!

 

[Jerry Treiman]

I would just add a word of caution about some jeweled barrels, safety barrels or motor barrels. Some of these (notably Waltham barrels with jeweled mainwheel) require disassembly of the arbor before the mainspring can be accessed. If one tries to just press out the cover using the arbor they can damage the entire assembly.

 

[DeweyC]

Speaking of barrels, I just did an elgin BWR Gr 240. I replaced the mainspring. Winders were no help, the arbors were not big enough. Plus the sprig goes in reverse of "normal". Then there is the hook to deal with.

Wound up putting the barrel in a collet of a 102 lathe. Installed the main wheel. Turned the lathe by hand while holding the main wheel and pressing it into the spring. Took some fiddling to get the hook to seat.

Spring is too strong to wind by hand.

 

[rstl99]

Thanks for the suggestion to put the barrel in a collet Dewey and turn by hand on the lathe. Indeed some of those old springs are strong - especially on the old verge-fusee watches I like to work on, plus on those the spring winds the "other way" (as you indicated for your watch), making usual winders not applicable. Cheers.

 

[gmorse]

Hi Robert,

Since nearly all fusees have a spring that's wound the 'wrong' way, and sets of left-handed winders are expensive, I either put an extra hook facing the opposite way in the winder arbor, (Bergeon pattern), or make a brass arbor that fits the collar and is held in a stout hand vice.

Regards,

Graham