Main Spring repair (self inflicted)

[Michael]

Purchased an automatic mainspring instead of a manual from Cousins. A bit pee’ed off at my mistake, so tried the repair. Any tips or advice from the experts will be gladly received on how to improve the process (if there will be a next time) The photos are pretty self explanatory to the process I tried. I used superglue to hold the 2 pieces in place before drilling and riveting, then will acetone it all away at the end. (For some reason the last photo should be the first photo)

[Klassiker]

The riveting looks good. What steel did you use? Did you turn the rivets with a head, or rivet both ends? How did you make the holes and the chamfers? How did you remove the automatic bridle? I like the idea with the superglue. Did you chamfer the end of the hook, so that it doesn't slip off the step in the barrel wall? Lots of questions I know, but the devil is in the details!

[HectorLooi]

Good old fashioned riveting. Nice job.

I would have just spot welded it. 

[Michael]

2 hours ago, Klassiker said:

The riveting looks good. What steel did you use? Did you turn the rivets with a head, or rivet both ends? How did you make the holes and the chamfers? How did you remove the automatic bridle? I like the idea with the superglue. Did you chamfer the end of the hook, so that it doesn't slip off the step in the barrel wall? Lots of questions I know, but the devil is in the details!

Hi Klassiker,

I used mild steel as I thought it would give a bit more when hit. I turned the rivets with a chamfered head, and ended up hitting both sides with the staking punch as it just felt more secure to do it like that. I snipped off the automatic bridle and used a bit of it for the hook piece. I did not chamfer the end of the hook - fortunately it is not in the barrel yet, so I will do that - thanks, I knew I woiuld learn something on this forum!! And the holes were drilled on a drill press and then chamfered with a bigger sized drill.

Hi Hector, I did think about soldering. It would be a lot quicker. I did not try that basically because I have never seen a main spring soldered as a repair. What do you think? I could heat protect the spring to the end and try a little silver solder, or I have some flux for soft solder that works with stainless steel so I might get a half decent joint with that?

Thanks both for your replies.

 

[HectorLooi]

I have seen a method in an old book where the end of the spring is annealed then folded over and hammered flat.

I tried it on a broken spring that I had but it snapped everytime. Maybe my spring was already fatigued or the steel in the old days was different.

[HSL]

Think it is a good work put into that repair.

Just as @HectorLooisaid there is an alternative method to do it, think it is Donald de Carles great books he thinks of, they are well worth investing in.

Here is his riveting method.


And the forming method.