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How do I support sweep seconds pinion to fit hand (Longines 30LS) ?


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Morning peeps. Here's today's puzzle !

I'm ready to case this Longines 30LS, and realised I'm going to have to support the sweep seconds pinion to fit the hand, as it's only held in place by a spring.

Problem is, if I put the movement on a flat surface, the pinion moves down too much and I can't get the hand on, and I can't see an easy way of putting a stump over the pinion to support it without possibly damaging the fourth wheel.

The movement dates from 1958, did Longines have special movement holders back then to support the pinion?

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Tricky one. The earlier 10L has the cock inverted so the pinion would be supported by the jewel…

image.thumb.jpeg.f5468732cc9a587e9a498e12c96ecda1.jpeg

If you could invert the pinion cock you’d be home free…but could you make a little ‘jig’ out of pithwood or something soft in the shape of the cock that would support the pinion, either curved like a C to avoid the 4th wheel, or a stick with a hole and countersink to let the pinion drop a bit and let you avoid putting pressure on the wheel?

I have one of those Bergeon delrin tools with nice countersunk holes but I think it would be too wide to avoid the plate for the 4th wheel…

IMG_0441.jpeg.f9a548aeec914e4b06713e9d2ebbb5a8.jpeg

 

Edited by rehajm
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I put a piece of broken mainspring between the friction spring and pinion, then support the whole lot on a small stump and press the hand on with the staking tool. If you just support the spring, the pinion can make an indent in it.

An extra arm and hand would be nice, but I hold the movement in the left hand, come down over the staking tool with it's back to the left, and situate the movement on the stump. I do put a little Scotch tape on the stump to avoid scratches.

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51 minutes ago, nickelsilver said:

 

I put a piece of broken mainspring between the friction spring and pinion, then support the whole lot on a small stump and press the hand on with the staking tool. If you just support the spring, the pinion can make an indent in it.

 

Yah, those little springs always have indents in them from pressing, don’t they? Especially when the end looks like a spanner…

You said you had trouble avoiding the wheel using a stump so I didn’t go this way. How about a flat pusher from a Seitz tool?

..or, inverted DU…

IMG_0442.thumb.jpeg.74079128ec5c9c27fc53b62c1e92aedc.jpeg

use a press to get the hand to stick properly oriented, then stand the movement on its side and fiddle with a hand tool for final positioning..

 

Edited by rehajm
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40 minutes ago, nickelsilver said:

I put a piece of broken mainspring between the friction spring and pinion, then support the whole lot on a small stump and press the hand on with the staking tool. If you just support the spring, the pinion can make an indent in it.

An extra arm and hand would be nice, but I hold the movement in the left hand, come down over the staking tool with it's back to the left, and situate the movement on the stump. I do put a little Scotch tape on the stump to avoid scratches.

Good idea putting something under the spring. I might try a bit of brass sheet. Sounds fiddly, but I'll give it a go 🤣 

The fourth wheel is the one part I replaced, (too much wear on the side of one pivot), so I'll be very peeved if I damage it.  I was amazed when I got this watch. It looks like it hasn't been serviced more than once or twice since 1958 - hence the wear on the pivot. Most screw heads look untouched !

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11 minutes ago, mikepilk said:

was amazed when I got this watch. It looks like it hasn't been serviced more than once or twice since 1958 - hence the wear on the pivot. Most screw heads look unto

…God bless the blokes what tossed it in a drawer and just bought a new watch! 🫡

Edited by rehajm
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1 hour ago, nickelsilver said:

I put a piece of broken mainspring between the friction spring and pinion

Exactly how I do it without denting the brake spring, although half the time it has already been dented!

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Well that was fiddly. Held some old mainspring in place with Rodico. Hand held the movement in the staking set over a small flat stump, and hoped for the best 🫣

image.png.1f83694af58a9d93dbc17780408d26c6.png 

I need to do some tweaking with the spring as the seconds hand is juddery. I put a drop of 9010 on top of the pinion. I guess it would be better without?  

I hate these springs - It's one of the things I dislike about some Omega movements.

 

 

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I was a bit confused by the pro advice here- OH answered one question by moving the spring out of the way but help me learn: when pressing the hand isn't all the pressure on the tip of the pinion pivot? …and I see something Jon once taught me in a similar configuration- should the pinion spring rest to the side of the pivot, not on top?

…I hate these springs, too. I had one missing in a 10L movement for a Weems. For the same movement they come in several shapes and lengths and secure to the movement in multiple, apparently random positions. The worst…

Edited by rehajm
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Yeh it's confusing. All the pressure is on top of the pinion when fitting the seconds hand.

I have a Longines 12.68ZS (pic) where the spring is a fork and goes under the pinion top. I have Omega's where the spring goes either over (Cal 565) or under (Cal 613) the top of the pinion. But it all these cases, there is a jewel, or solid surface just above the pinion, so it doesn't need the same support when fitting the hand.

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1 hour ago, Jon said:

Exactly how I do it without denting the brake spring, although half the time it has already been dented!

These are just the sorts of tips we need !

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1 hour ago, mikepilk said:

hate these springs - It's one of the things I dislike about some Omega movements

Ohh, I agree so much😫. Sorry, a bit off topic, but one day recently I felt like starting a thread with a rant against the Omega 55x (and some other series) which are sometimes hailed as the "greatest movements ever". I don't get it... Stupid tension spring, hardly serviceable reverser wheels, brass rotor bearings that are badly worn on pretty much every one I've seen so far (and to replace them properly, you need a specific reamer to get the bearing hole to fit the axle... otherwise they're too tight). 

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2 hours ago, rehajm said:

I was a bit confused by the pro advice here- OH answered one question by moving the spring out of the way but help me learn: when pressing the hand isn't all the pressure on the tip of the pinion pivot? …and I see something Jon once taught me in a similar configuration- should the pinion spring rest to the side of the pivot, not on top?

…I hate these springs, too. I had one missing in a 10L movement for a Weems. For the same movement they come in several shapes and lengths and secure to the movement in multiple, apparently random positions. The worst…

It should rest on top. While the Omega one go underneath.  

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13 hours ago, HectorLooi said:

Aliexpress has a table to support the centre seconds pinion.

Stainless steel needle holder universal top movement fixed seat press watch pointer watch maintenance tool
https://a.aliexpress.com/_mN7sksX

 

You still have to manually hold the movement - so I just use a small stump on the staking set.

As expected, to stop the jerky seconds hand, I needed to remove all traces of oil between the tip of the pinion and spring and increase the spring pressure. It's the friction/stiction which prevents the uneven motion - not a very elegant solution. And if you overdo the spring tension it kills amplitude.  But the timegrapher looks OK (I would expect a bit more amplitude from one of these movements, but I didn't change the mainspring and there is slight scoring on some train gear pivots - it seems to have been run for many years without a service).

20250117_150415.thumb.jpg.262f1b8737120ddc27811241c09b9acc.jpg

Edited by mikepilk
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