UK Watch Forum banner

Hairspring end curve

6 reading
0 views 5 replies 4 participants last post by  Fergie307  
#1 ·
Sorry if this sounds daft but I’m new to this … I have just replaced a hairspring balance complete with an original new one but it doesn’t have an end curve . So the balance staff is nowhere near the balance cock jewel hole. What is the best way to form an end curve or am I missing something .
Thanks
 
#3 ·
Chronoglide watchmaking. He has done at least one video covering how to reshape hairsprings.
Agree a picture would help.
If the out curve is big then always an idea to shape it initially to cater for the regulator at the fully slow position. That way the regulator can move through it's full arc without pulling the spring to one side.
 
#4 ·
Re-shaping a hairspring is a tricky one to give advice on, especially if you have not attempted this before. It's very easy to make a mess of it and very difficult to recover from mistakes. As @Fergie307 mentions, have a look at some videos to get an idea of what's involved and the tools you'll need.
Is the old hairspring still in a condition that you could compare with to get an idea where adjustments are needed?
Also, may be an idea before attempting to adjust your new hairspring, to get hold of another scrap hairspring to practice making adjustments on and get a feel of how delicate you'll need to be.
 
#5 · (Edited)
Really good advice to practice on some scrap ones.
You will see many people using a fine right angled pick. Very good both for detangling and shaping. I make mine just by heating and bending a fine sewing needle. Either put a handle on it or grip it in a pin vice. You also need some good quality tweezers.
I first started by getting some fairly large pocket watch springs. Easier to see what you're doing whilst you get the hang of the different techniques for shaping, and correcting coning etc. You often find job lots of them on e bay etc for not a lot of money.
 
#6 ·
One thing you need to consider is timing. Reshaping the spring will change the position of the wheel so changing the beat.
What I do as a guide is to make a mark on the top of the wheel in line with the impulse pin or jewel, a dot with a Sharpie for example. I actually have some shocking pink nail varnish I use for this! Even the tiniest dot shows up really well, and removed in seconds with a q tip and some acetone.
Put the balance cock on without the wheel and set the regulator so the end is in line with the centre position of the lever. Now take the cock off and hold the wheel in place in the upturned cock, with the impulse in line with the regulator. Make a further mark on top of the wheel in line with the mounting post for the spring. Now when you come to refit the spring you can see where you need to position the end relative to the wheel to have it in beat. Once you have mounted it remove the post mark. If you don't have a time graph then you can use the mark in line with the impulse to time it.
With the watch running look to see where the mark stops before turning back the other way. Mark this on the movement, or take a picture of it and make marks on that. Do this on both sides so you have the limit of movement in both directions.
Measuring the angle between the marks and the balance pivot will tell you the amplitude. Where they are in relation to the centre position of the lever will tell you if it's in beat. If it is out it will also tell you which way to turn the collet to correct it.
Can be surprisingly accurate if done carefully, and of course this, or a similar method, was the only way of doing it prior to the invention of time graph type machines.