Repair of mainspring

[dnhb]

On opening the barrel of a Lancashire Watch Co Ltd pocket watch I found that the spring had snapped about 1cm from the arbour. I'd be grateful for advice as to how to go about creating a slot at the start of the remainder of the spring so it can be connected to the arbour - I imagine creating and shaping an appropriate hole in spring steel is not that straightforward. (I bought the watch, which is incomplete & in very poor condition, for a few pounds intending to use it as a 'learning' piece. There is nothing to identify the watch other than the company name on the dial (which is of badly cracked & chipped enamel) and "No. 85590" engraved in script on the barrel bridge.)

[watchweasol]

Hi if this is to be used for playing with to learn then trying the spring repair is ok .. first remove rather rest of the spring from the barrel  then anneal about 1 to 1 /2 cm from the end  then drill a hole in the spring and reshape with a needle file.. with round nosed pliers re curve the spring end to receive the arbour . The end without the arbour should fit round the arbour hole in the barrel. Not a difficult procedure but time consuming.

[RichardHarris123]

I have seen mainspring punches on ebay, how effective they are, I don't know. 

[dnhb]

On 2/12/2024 at 9:36 PM, watchweasol said:

Hi if this is to be used for playing with to learn then trying the spring repair is ok .. first remove rather rest of the spring from the barrel  then anneal about 1 to 1 /2 cm from the end  then drill a hole in the spring and reshape with a needle file.. with round nosed pliers re curve the spring end to receive the arbour . The end without the arbour should fit round the arbour hole in the barrel. Not a difficult procedure but time consuming.

Thanks for the advice. Just to be sure: to anneal I heat the area to cherry red & then allow it to cool? After creating the hole do I restore the 'spring' character of the metal by re-heating and then quenching ? Re RH123's comment, does one treat the metal similarly before (& after?) using a mainspring punch?

[watchweasol]

Hi having annealed the spring end and reshaped a made thr hole  leave it alone, the last inch of springs is relative soft incase you need to form it slightly to pick up on the arbour. I have had new springs that required a gentle coaxing.