Main Spring

[don1954]

Hey Bob,
Im working on that eight day clock and got the movement done but i just cant get the main springs to catch on the arbor. I have used a screw driver to hole the srping down and when its aalmost wound fully the spring will jump off the arbor pin this is on both springs. Is there an easy way to get the spring to catch and hold? This is driving me nuts.
Thanks Bob, Don

[arutha]

Hi Don,
I have this problem quite a lot, first check the spur on the arbor to make sure its not rounded, it should have a dead flat face or a slight hook to it. Next look at the eye on the inner coil of the spring to make sure it is not distorted. Its not unknown for the eye to distort as the ends of the springs are left soft. If all looks good you need to grab the inner end of the spring and bend it into a tighter c shape, if it goes L shaped it wont work. I know at times I have had so much trouble with mainspings not being picked up by the arbor, it all looks fine but just wont grip, very frustrating! Good luck and let us know how you get on.
Paul.

[don1954]

Thanks Arutha,
I’m looking at both spurs they look ok an when i look in at the inner coil when i put the arbor back in it is tight against the arbor. The dang thing worked fine until i took the spring off to clean and oil it lol. of course i cant see the spur when it goes into the eye. It seems that the spring is not going under the spur all the way to catch real good because when i wind it it holds good until its wound all the way thats when the spring jumps off the spur. i’m thinking maybe i should take a punch and drive the spur out of the arbor a little so the spring can slip under it better.
Thanks Don

[willofiam]

Hi Don, Paul has great advice (as always) you said “I have used a screw driver to hole the spring down” I dont think you should have to hold down the mainspring with a screwdriver it should, if bent around the arbor, automatically grab and hold with the tension created when winding. this is probably a dumb question but I did this once, are you putting them on the right way????? also are you winding them up on a mainspring winder or in the works??????? I also dealt with one that would not hold, it was because the end of the hole was tore and the torn part was bent towards the arbor and pushed the mainspring off the pin……..but this one would release way before fully wound..I do on occasion have them “skip” when first winding up, I use a mainspring winder, but after it catches and I wind it up fully and carefully the issue goes away, maybe its the air up here as Paul mentioned @Arutha wrote:

If all looks good you need to grab the inner end of the spring and bend it into a tighter c shape

and the end of the mainspring curls around the arbor enough then the next coil will hold it into place and it should not let go, anyway, just me thinking out loud, let us know Don.
P.S.Does anyone have access to a chart that would give original mainspring sizes for specific clocks, It sounds like Lou at mile high clock supply is putting one in his new catalog which is coming out soon but I would like to gather as much info on that as I can.

[don1954]

im using a webster mainspring winder, i’ll keep messing with it it all looks good and yes i thought maybe i was going backward but no i looked at the end of the spur and can see where it slips over it it leaves a mark. i dont get it it worked fine before i tokk it apart to cleaan it

[willofiam]

is the 2nd wrap around already tight to the hole before you put the arbor in????

[arutha]

Like I said earlier I have had the same thing, springs wound fine until I stripped and cleaned. The most common cause Is the inner loop is bent slightly out of shape. Some of these mainsprings are very soft at the ends and it dont take much to bend it out of shape, even just a slight twist to the loop end can cause problems. If you are saying that this is a tight fit around the arbor and the spring jumps of when almost fully wound it can only be one of two things, the eye on the inner loop has a tear or is distorted or the spur has worn. If you are 100% positive the inner loop is ok then it has to be the spur on the arbour. One other thing that might be worth checking is where the arbour goes through the barrel and cap, are these holes worn excessively allowing the arbor to move so much it can disengage with the spring?

[willofiam]

Paul you brought up something I wasnt even thinking about, is it a housed mainspring or not, if it is then yes there are other things to look at. My bust, thanks, William

[don1954]

well guys i feel like a nut, it wasnt the spring slipping off the spur it was the arbor slipping inside the collet on the winder. i started watching things closer an caught a little bit of metal fly out of the collet so i marked the collet and the arbor, when the spring slipped i looked at my mark and there it was way off,
Thanks guys Don

[arutha]

Dont feel bad Don, just be very glad you have got to the bottom of the problem. If you get the time post up a pic of the clock so me and William can get to see what we have been talking about. Good luck
Paul.

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