seized screw .... help

[LeCorbusier]

Hoping some one has some advice for freeing up a seized ratchet/barrel arbor screw. The screw doesn't appear to have any movement in it and I am nervous of applying any more pressure as I don't want to either sheer it or strip out the head slot. The watch is an old trench watch movement. What would be a sensible method for tackling the dismantling?

 

Thanks

 

Tim

[Neverenoughwatches]

19 minutes ago, LeCorbusier said:

Hoping some one has some advice for freeing up a seized ratchet/barrel arbor screw. The screw doesn't appear to have any movement in it and I am nervous of applying any more pressure as I don't want to either sheer it or strip out the head slot. The watch is an old trench watch movement. What would be a sensible method for tackling the dismantling?

 

Thanks

 

Tim

Hi. Just asking that you have checked for a reverse thread. Post up some pictures please

Edited September 9, 2022 by Neverenoughwatches

[Jon]

28 minutes ago, LeCorbusier said:

Hoping some one has some advice for freeing up a seized ratchet/barrel arbor screw. The screw doesn't appear to have any movement in it and I am nervous of applying any more pressure as I don't want to either sheer it or strip out the head slot. The watch is an old trench watch movement. What would be a sensible method for tackling the dismantling?

 

Thanks

 

Tim

Every now and then you'll come across a ratchet screw that is a left handed thread. I'm not saying that is the case here, but it is worth noting

[LeCorbusier]

22 minutes ago, Jon said:

Every now and then you'll come across a ratchet screw that is a left handed thread. I'm not saying that is the case here, but it is worth noting

How does that work with the click .... normally it is the click that seems to allow you to unscrew the wheel?

[Neverenoughwatches]

21 minutes ago, LeCorbusier said:

How does that work with the click .... normally it is the click that seems to allow you to unscrew the wheel?

Pictures please matey.

[LeCorbusier]

1 minute ago, Neverenoughwatches said:

Pictures please matey.

My phone is out of charge ... busy re-charging at the mo - haven't ignored your request 

 

[LeCorbusier]

question .... do ratchet screws on old movements have a tendency to seize or if it won't apparently budge is it more likely to be a reverse thread ... if so and without being able to use the click how would it be best to get some purchase?

I have left it overnight soaking in penetrating oil.

Thanks

Tim

 

[Jon]

Any screw, especially on vintage watches have a habit of being really tight every now and then.

I know I mentioned a left handed thread, but I've only read about it and have never come across one on a ratchet screw myself, although I have come across left handed dial screws, which even had three cuts in the heads to denote that fact. No reason to have them as a left handed thread either, buy hey...

I would have put it in penetrating oil as well. If you do manage to grip the ratchet wheel, it would be safer than holding back the barrel teeth, as they are likely to break very easily, although depending on how much pressure you have to put on the screw. you might damage the teeth of the ratchet wheel if you're not careful. I would use a 3 mm acrylic stick fashioned on the end like a screwdriver blade, so you can jam it between the bridge and the ratchet wheel teeth. If anything will give first it will be the acrylic stick, rather the a tooth. The thicker the end of the stick is the more resistance before breaking, so experiment and start with a low breaking point and work up. I use them all the time to pry off bridges and hold them down, as well as keeping the ratchet wheel still whilst screwing it down, as they don't flake like some pegwood

Edited September 9, 2022 by Jon

[HectorLooi]

Your ratchet wheel screw doesn't appear to be rusted. Most likely it's a left hand thread.

Make sure your screwdriver blade is well dressed to avoid slipping and damaging the screw slot. Apply torque in both left and right directions and feel/look for any movement. Use a gentle force initially, then increase the torque gradually.

Sometimes heat is required to loosen the screw. I use a soldering iron to touch the head of the screw for a few seconds to heat it up.

Good luck and don't be impatient.

[LeCorbusier]

Bingo .... and thanks everyone. Soaking overnight plus a little very gentle heating with a fine soldering iron and it came loose .... it was a reverse thread as you all thought. 

 

[Neverenoughwatches]

39 minutes ago, LeCorbusier said:

Bingo .... and thanks everyone. Soaking overnight plus a little very gentle heating with a fine soldering iron and it came loose .... it was a reverse thread as you all thought. 

 

Glad you got it sorted mate. Without knowing its left hand threaded HectorLooi's suggestions to sensitively feel for freeing movement is the ideal practice for proceeding with caution. 

[LeCorbusier]

Yep ... it was spot on. It was still very tight and needed both a little heat and a fair bit of torque - though I do wonder initially how much of the problem I caused trying to unscrew the other way. Luckily I stopped and posted the question - it never occurred to me it might be reversed threaded but was uncomfortable to apply any more force. Phew!

[Neverenoughwatches]

1 hour ago, LeCorbusier said:

Yep ... it was spot on. It was still very tight and needed both a little heat and a fair bit of torque - though I do wonder initially how much of the problem I caused trying to unscrew the other way. Luckily I stopped and posted the question - it never occurred to me it might be reversed threaded but was uncomfortable to apply any more force. Phew!

Good call. Yep you may have nipped it up a bit tighter on your first attempts. I snapped a rachet wheel screw on one of my first repairs. I did know but completely forgot, so used to standard threads from my job. I've screwed that way for years  ,( said the actress to the bishop ).

[dadistic]

It's hard to break habits like lefty loosey righty tighty. I just broke one myself, I was even thinking to myself "left handed screw" and I *still* turned it the wrong way. 

Sheesh.

[LeCorbusier]

I now have the movement cleaned and running without a snow shower on the timegrapher.

I could do with a little diagnostic help .... bearing in mind that this is an oldish movement.

The beat error is quite large at between 8.7 and 9.2 fluctuating. Amplitude is sitting a little over 210 though dips to 95 and reads up to 219. The rate fluctuates between +40 and  -20.  The change is gradual and it sits at around +3 for quite a period and in the +20s for quite a period before dropping of to the -20s and then righting back to the +3s again.

Would be interested in advice here - I will look at the beat error to bring it below 1 - but what might be causing the fluctuation? The drop in amplitude appears to correspond to the negative reading on rate.

Readings:-

+38 : 211degrees : 8.1ms

+23 : 207 degrees : 8.2ms

+16 : 203 degrees : 8.6ms

-11 : 194 degrees : 9.0ms

-38 : 185 degrees : 9.6ms

Tim

 

edit ... when I turn to different positions things go a bit haywire .... amplitude drops to 160s and rate in some positions runs fast (+200s) and in others slow .... beat error constant.

Edited September 11, 2022 by LeCorbusier

[Neverenoughwatches]

13 hours ago, dadistic said:

It's hard to break habits like lefty loosey righty tighty. I just broke one myself, I was even thinking to myself "left handed screw" and I *still* turned it the wrong way. 

Sheesh.

How about for rachet and crown wheel screw # rachet risky reversey # ?

[LeCorbusier]

Got right to the end of an epic rebuild of the trench watch with it actually running quite well .... and then went and broke the balance staff pivot  ... and that was after having re-studded the hairspring and manipulated it back to the correct shape so was feeling well chuffed ... classic pride before a fall and taking my eye off the ball. I had just tweaked the collet to fine tune the beat error and was careless when refitting the balance and BANG!.

So .... the question is ... is it possible to buy a replacement staff for an old watch like this, and if so how would I get the right size?

[Neverenoughwatches]

3 hours ago, LeCorbusier said:

Got right to the end of an epic rebuild of the trench watch with it actually running quite well .... and then went and broke the balance staff pivot  ... and that was after having re-studded the hairspring and manipulated it back to the correct shape so was feeling well chuffed ... classic pride before a fall and taking my eye off the ball. I had just tweaked the collet to fine tune the beat error and was careless when refitting the balance and BANG!.

So .... the question is ... is it possible to buy a replacement staff for an old watch like this, and if so how would I get the right size?

Aw mate gutted for you but really well done on the rest of the repair, the thing is not to let it set you back. It may not have been totally your fault, an old watch so could easily have been an old weak pivot that has given years of service. Lets have a gander of the watch and movement matey, i dont think we've seen it yet. 

[LeCorbusier]

this is the watch

It's an 11 lignes (24.8mm) movement ... Stamped AS 

[Neverenoughwatches]

33 minutes ago, LeCorbusier said:

this is the watch

It's an 11 lignes (24.8mm) movement ... Stamped AS 

Adolph schild. Good start so now just t he calibre to identify. Any numbers or letter ing to go with that 

[LeCorbusier]

Not that I have found ... Balance Staffs.com have the following numbers as 11 lignes - 178, 317 and 267, 367 .... but no image of the movements.

 

The balance bridge has 38 stamped on it

 

otherwise it is stamped swiss made.

 

[Neverenoughwatches]

13 minutes ago, LeCorbusier said:

Not that I have found ... Balance Staffs.com have the following numbers as 11 lignes - 178, 317 and 267, 367 .... but no image of the movements.

 

The balance bridge has 38 stamped on it

 

otherwise it is stamped swiss made.

 

Ranfft has a few listed 38x similar keyless works but different train. Mid 1930s . Can you assemble the rest of the keyless . it may be too old for some identification sources.  your only option maybe to repivot the staff or have a new one made if you are determined to carry on. 

Edited September 24, 2022 by Neverenoughwatches

[LeCorbusier]

I have been perusing the Best Fit Manual .... under AS I came up with the two following calibers which were 11 ligne .... 

Both state compatibility with AS 635 - the illustration for 635 is - 

The yoke on this seams correct for my movement

The recommended balance staff is given as 72

 

This would match with the Ronda staff illustrated  here..

If I get a close measurement of my staff to this (given the the pivot is broken) is this reasoning sound? 

[Neverenoughwatches]

2 hours ago, LeCorbusier said:

I have been perusing the Best Fit Manual .... under AS I came up with the two following calibers which were 11 ligne .... 

Both state compatibility with AS 635 - the illustration for 635 is - 

The yoke on this seams correct for my movement

The recommended balance staff is given as 72

 

This would match with the Ronda staff illustrated  here..

If I get a close measurement of my staff to this (given the the pivot is broken) is this reasoning sound? 

That should be a fair bet, providing you can accurately measure the staff, you will be just missing measurement A. How do   the rest of the keyless works match up to give a more solid ID. I am also assuming that you have staking equipment? 

Edited September 25, 2022 by Neverenoughwatches

[LeCorbusier]

Yes I have a staking set ... The setting lever looks very similar ... but it doesn't have the spring at all.

I will see if I can extract dims from the staff and take it from there I think ... if it doesn't match I can always search for one that does I suppose.