Mechanical WW Mainspring barrel help on Felsa 4009 or similar

John Tebeau

Registered User
Aug 21, 2020
7
1
3
Howdy,
Trying to service wrist watch with Felsa 4009 movement. Not sure how to proceed. Never seen one before. Thanks.

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John Tebeau

Registered User
Aug 21, 2020
7
1
3
Hmmmmm, looks like it might require a new mainspring once disturbed or could just roll the dice and leave ‘as is’. The movement is in an Avia King 25j I just acquired. Think I may have to just roll’em and see what transpires.....Thanks for the help.
 

D.th.munroe

Registered User
Donor
Feb 15, 2018
675
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BC Canada
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It shouldn't need a new mainspring after coming apart unless it needs a new spring for other reasons.
These come apart quite easily by pulling apart while holding the barrel and turning the wheel the arbor is connected to a bit the opposite way of winding to unhook the inner hook.
I cheat and use thin flat tweezers to hold the spring in the barrel and push the arbour out from the bottom of the barrel and they just pop out. Then proceed like any other spring.
Dan
 

John Tebeau

Registered User
Aug 21, 2020
7
1
3
Thanks, that does make sense.

The movement was pretty clean so I am debating if it would be the better part of valor to leave the barrel alone. I know some will cringe at that.

How would you approach the process of getting it back together. Would seem to be a blind operation fraught with peril. Do you wind and insert the spring into the bottom half and then wiggle the top half into position so that the tang will hopefully engage the mainspring key by turning the ratchet/arbor in the proper direction? Would a winder potentially enlarge the spring inner coil so that it will no longer be able to catch the center tang? Should it be hand wound instead in a case like this?

I appreciate your help with this. Seems every watch takes me down a new path.....
 

D.th.munroe

Registered User
Donor
Feb 15, 2018
675
236
43
39
BC Canada
Country
Region
Do you wind and insert the spring into the bottom half and then wiggle the top half into position so that the tang will hopefully engage the mainspring key by turning the ratchet/arbor in the proper direction? Would a winder potentially enlarge the spring inner coil so that it will no longer be able to catch the center tang?
Yes basically. Usually they catch quite easily.
Most winder arbors are (or should be) roughly the same size or a bit smaller than the barrel arbor and usually don't distort the inner coil too much, so using a winder shouldn't be a problem.
If it's your watch, leaving it is fine, you can always do it when you feel more comfortable doing it. Though it may wear more and need replacing if it was dirty.
Dan
 

John Tebeau

Registered User
Aug 21, 2020
7
1
3
Yes basically. Usually they catch quite easily.
Most winder arbors are (or should be) roughly the same size or a bit smaller than the barrel arbor and usually don't distort the inner coil too much, so using a winder shouldn't be a problem.
If it's your watch, leaving it is fine, you can always do it when you feel more comfortable doing it. Though it may wear more and need replacing if it was dirty.
Dan
Thanks again. I think I can picture how this should be done finally.

You make a good point. It IS just for me to repair and file away. Watch came running but crown not winding. Disassembled and found that the ‘crown wheel’ is on the underside of the barrel bridge (another new one on me) and was jammed by a plate post. Problem solved. Then got to looking at the unusual barrel. “Nothin’s Easy” has become my motto.

I fiddled with the barrel some rotating it back and forth a little. If I can get a good grip on it I’ll try to push the envelope a little more. A fiddly part to manipulate with the fingers. Do you have any words of wisdom on a simple way to handle it? Maybe hold the bottom into rodico and rotate the top?

Again I appreciate your help providing clarity so it begins to make some sense.
 

John Tebeau

Registered User
Aug 21, 2020
7
1
3
Thanks again. I think I can picture how this should be done finally.

You make a good point. It IS just for me to repair and file away. Watch came running but crown not winding. Disassembled and found that the ‘crown wheel’ is on the underside of the barrel bridge (another new one on me) and was jammed by a plate post. Problem solved. Then got to looking at the unusual barrel. “Nothin’s Easy” has become my motto.

I fiddled with the barrel some rotating it back and forth a little. If I can get a good grip on it I’ll try to push the envelope a little more. A fiddly part to manipulate with the fingers. Do you have any words of wisdom on a simple way to handle it? Maybe hold the bottom into rodico and rotate the top?

Again I appreciate your help providing clarity so it begins to make some sense.
Follow up. I did get the thing apart. Gonna clean the spring and hope for the best in reuniting the parts.
John
 
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