Eta 2783 Mainspring Grip On Barrel Arbor

[canwdarose]

Everything is going well on my ETA rebuild, but I got the new mainspring in and this is what it looks like. My Seikos all have a really snug twisting shove required to engage the arbor, then an audible 'click' when the arbor lug engages the mainspring slot. Any suggestions on adjusting the grip - if I do nothing, the watch won't wind....

[clockboy]

Looking at the pic the inner coil is not snug around against the arbour. If I am correct it will need manipulating. 

I have found the best way to do this without breaking the spring is to use these hairspring tweezers with support for the middle (I use a tack). The support for the middle  is very important because it is very easy to snap the spring.

 

[oldhippy]

When I had this situation I always used round nose pliers. As clockboy has said be careful not to snap the spring. 

[jdm]

I have found the best way to do this without breaking the spring is to use these hairspring tweezers with support for the middle (I use a tack). 

 

Where these can be bought?

[oldhippy]

Any watch tool suppliers should have such tools.

[jdm]

Any watch tool suppliers should have such tools.

Any link to share ?

[bobm12]

ofrei.com.....they are very expensive. Or maybe ebay, when they show up.

[dadistic]

Looking at those tweezers, I always thought they were just used for forming a breguet overcoil. Interesting that they can be used for adjusting mainsprings. Do you use them for other purposes, too, such as general hairspring manipulation?

 

thanks,

 

David S

[jdm]

ofrei.com.....they are very expensive. Or maybe ebay, when they show up.

Thanks Bob. Ofrei only seems to have these (used) ones.

 

 

"for HS marking". Attached Dumont catalogue which has various more specialized HS tweezers. I do not see any of these from the usual suppliers, perhaps by special order.

dumont_catalogue_watchmaking.pdf

[jdm]

Looking at those tweezers, I always thought they were just used for forming a breguet overcoil. Interesting that they can be used for adjusting mainsprings. Do you use them for other purposes, too, such as general hairspring manipulation?

Indeed the catalogue attached above references them for use on Breguet HS. But I think that if if the shape fits the need, can be used for other purposese.

[bobm12]

They are Horotec tweezers, though. I forgot to mention that.

[jdm]

They are Horotec tweezers, though. I forgot to mention that.

 

 

 

From the marking I suppose these are equivalent to Dumont's No 10, in sizes from 000 to 8, see catalogue attached above. 

[Alaskamick]

Hi, just my twopence worth and not wishing to offend anyone.

 

I cant't believe that anyone would use hairspring tweeters or in fact any normal tweezer, which can cost an arm and a leg, to bend mainsprings.

 

I think any daily use tweezers would be wrecked.

 

Surely you would have to use small pliers.

[cdjswiss]

And here's my halfpenny worth:

 

I would not use my precious overcoil pliers on mainsprings, even if I had a large enough size.. This is what I use: inexpensive and does the job perfectly.

[oldhippy]

And here's my halfpenny worth:

 

I would not use my precious overcoil pliers on mainsprings, even if I had a large enough size.. This is what I use: inexpensive and does the job perfectly.

round-nosed pliers.jpg

That's the sort I always used.

[cdjswiss]

 Correction : in my previous post please read overcoil tweezers instead of overcoil pliers.  I should also have pointed out that because of the taper, the round nosed pliers should be used gently on one side and then the other of the loop that is being closed.

 

Another, perhaps better, suggestion is to make an overcoil-type pair of tweezers of large size, depending on the size of the mainspring barrel arbor, from a stout pair of brass tweezers. I have dug out this example that I used a couple of times before acquiring the pliers. The shaping was done with a couple of needle files; one round for the concave side and a flat one for the opposite side.

 

Edited January 25, 2016 by cdjswiss

[oldhippy]

I should also have pointed out that because of the taper, the round nosed pliers should be used gently on one side and then the other of the loop that is being closed.

 

I would have thought that would be common sense.

[cdjswiss]

You would.

[canwdarose]

Well, I've certainly learned to wait at least 24 hrs before looking at any replies from a post - thanks to everyone for the info and photos and discussion about meaning and intent. As the replies unfolded, it became increasing clear that one insets the hefty tweezers/small pliers into the center and grip the spring and slowly and carefully bend in an overcoil, without concentrating all the bending in one location. The curved jaw to the interior and the flat jaw to the exterior, and flip the spring to maintain parallelism to the arbor shaft while manipulating. I'll post a reply with the result.

[clockboy]

I purchesd the tweezers a few years ago of eBay but only have every used them on a clock hairspring.  But I found that the curved shape helps with the bending BUT the centre of the bend must be supported or it will snap.