Has this main spring been incorrectly fitted

[quantieme]

Hi all, as my title says has this been fitted incorrectly, I have never seen a spring fitted like this before ( except in a clock barrel) I am wondering is it because they could not find the right size spring and wanted to tighten it up as I cant see why it was not fitted direct to the barrel wall, I shall be replacing it anyway  but just need to understand why it cannot go directly in. If it makes a difference the watch is a 1960s pin pallet telemeter Cimier sport.

[Jon]

47 minutes ago, quantieme said:

Hi all, as my title says has this been fitted incorrectly, I have never seen a spring fitted like this before ( except in a clock barrel) I am wondering is it because they could not find the right size spring and wanted to tighten it up as I cant see why it was not fitted direct to the barrel wall, I shall be replacing it anyway  but just need to understand why it cannot go directly in. If it makes a difference the watch is a 1960s pin pallet telemeter Cimier sport.

It technically can go straight in without the thicker piece of metal that acts as the hook, although the end that is left is not a hook as it hasn't been flattened or rivetted or spot welded to make the hook strong enough to use, so it would more than likely snap when near full wind. The heavier piece of metal that does actually hook on the barrel wall puts force on the end of the mainspring in a different way. The force is directly on the bend on the end of the spring which can handle that force. In this way the bend on the end of the spring isn't trying to open up, as if it were fitted directly into the barrel

[quantieme]

1 hour ago, Jon said:

It technically can go straight in without the thicker piece of metal that acts as the hook, although the end that is left is not a hook as it hasn't been flattened or rivetted or spot welded to make the hook strong enough to use, so it would more than likely snap when near full wind. The heavier piece of metal that does actually hook on the barrel wall puts force on the end of the mainspring in a different way. The force is directly on the bend on the end of the spring which can handle that force. In this way the bend on the end of the spring isn't trying to open up, as if it were fitted directly into the barrel

thank you for that information, i am going to replace it anyway as it is rusty so i could put in a proper flattened or riveted spring in theory then.

[praezis]

1 hour ago, quantieme said:

i am going to replace it anyway

I would think twice.
Extra long Roskopf springs are no more available.

Frank

[Shane]

I have seen this within several older loose barrels I had kicking around.  My thoughts were that it was a way of salvaging a previously broken mainspring.  To that point (while working on the Waltham 1883 that I have carried every day for the last year and a half) I tried to duplicate this system.  The broken mainspring I used lost about .250 in/6 mm +- but was perfect in every other way.  I have not noticed any ill affects from this in accuracy or run time.  I do wind it completely once or twice daily.

If it ever breaks I will let you all know.

Shane

[nickelsilver]

I have a bunch of NOS springs with the 180 degree bend, ready for the inserted hook. They're blue steel, old. If the bend is tight, and the hook well formed (not too long and curved to match barrel wall) it's an excellent system- theoretically even better than standard springs with the hook rivetted/welded on.

 

But they're b!tchy to get in the barrel, and if not well done eat up real estate in the barrel. They tend to be found in cheap watches. But the concept is good.

[quantieme]

19 hours ago, Jon said:

It technically can go straight in without the thicker piece of metal that acts as the hook, although the end that is left is not a hook as it hasn't been flattened or rivetted or spot welded to make the hook strong enough to use, so it would more than likely snap when near full wind. The heavier piece of metal that does actually hook on the barrel wall puts force on the end of the mainspring in a different way. The force is directly on the bend on the end of the spring which can handle that force. In this way the bend on the end of the spring isn't trying to open up, as if it were fitted directly into the barrel

thank you for that information, i am going to replace it anyway as it is rusty so i could put in a proper flattened or riveted spring in theory then.

 

16 hours ago, nickelsilver said:

I have a bunch of NOS springs with the 180 degree bend, ready for the inserted hook. They're blue steel, old. If the bend is tight, and the hook well formed (not too long and curved to match barrel wall) it's an excellent system- theoretically even better than standard springs with the hook rivetted/welded on.

 

But they're b!tchy to get in the barrel, and if not well done eat up real estate in the barrel. They tend to be found in cheap watches. But the concept is good.

thank you all for your help and advice, I think I will leave it in situ, I  will clean it as best as I can and tbh for a pin pallet the watch was running ok even with the spring in that state but i have stripped and cleaned it, i remember trying to get a clock spring in a barrel that was fitted like that and it was a nightmare.