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Opening clock mainspring barrel


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After careful consideration, I think solder would not work very well for this repair. The solder joints would be subjected to strain, which caused the barrel to crack in the first place and we know solder joints fail under strain. 

I'm thinking of banding the barrel with a steel strap which is placed with some tension. I'm thinking of using a steel zip tie, if there is sufficient space between the barrel and the 2nd wheel.

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On 11/25/2020 at 3:16 PM, oldhippy said:

Did the cracks start to open when you installed the spring? if not then it should be OK. 

I installed the spring back inside the barrel yesterday and checked it this morning. The copper wire band is still holding.

But now I have a new problem with this clock. The strike mainspring is going to break at the eye. Is it possible to cut off the end and cut a new eye or should the spring be replaced?

20201126_225004.jpg

20201126_224932.jpg

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Apart from that end if the spring is in good condition you can as you put it cut a new eye.

There is a tool you can buy that will punch a hole in clock mainsprings. I preferred to do it the way my master used to do it. Cut the damaged part off and file it flat and filing rounded corners on the end.   You will need to heat around where the new hole is going to be until it is bright red then quench it in old oil or water. You then punch a few holes in it close together and then with needle files file it out into a shape like a pear so the narrow part fits onto the eye in the barrel. Make sure you file the entire burr away you do not want rough edges rubbing together as this will cause wear.

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Thanks OH.

I cut off the end and rounded off the sharp corners, then annealed about an inch of the spring. Then I traced the outline of the hole and used a high speed dental carbide bit to cut out the hole. 

This clock seems to have all sorts of hidden faults. I wonder what's next.

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