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Mainsprings

rduckwor

By rduckwor
in Watch Repairs Help & Advice

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rduckwor WRT Addict

rduckwor

Posted
Posted

You carefully measure an old mainspring and order a modern replacement.  It arrives and the "eye" or center loop is too large for the arbor.  Can a modern mainspring be adjusted and what is the recommended procedure?

 

Thanks.

 

RMD

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AndyHull Distinguished Member

AndyHull

Posted
Posted

You might get away with a pair (or two pairs) of round nosed pliers, with small "noses", something like this.

https://www.ebay.co.uk/itm/small-round-nose-BAIL-MAKING-jewellery-pliers-3-6mm-5-6mm-jaws-bsis-bl-sm/222883655206?hash=item33e4e6ae26:g:h2gAAOSwqu1aqlSw:rk:18:pf:0

Bending tempered steel is always a bit of a hit and miss affair, so I would be tempted to fit the spring in the barrel and see if you can catch the spring with the arbor and then press the arbor in to the hole, it may not need any bending at all.

 

 

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mikepilk Distinguished Member

mikepilk

Posted
Posted

I don't know if the hole end is more tempered than the rest of the spring, but I've never had trouble bending it, or have one break. 

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rduckwor WRT Addict

rduckwor

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Posted

Thank you all for your replies.  I have broken two now specifically at the center loop.  I guess it is a matter of practice until I get it right.

 

RMD

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