Jump to content

Stuck ratchet wheel screw


Recommended Posts

I'm working on an old AS984 movement from the 1940's and cannot get the ratchet wheel screw loose.  I've soaked it in numerous solutions  and even tried taping it on my staking set to loosen the crud that is binding the screw to no avail.  I'm starting to strip the screw head and don't want to continue  without reaching out to the forum.

What are my other options?

George

Link to comment
Share on other sites

2 hours ago, PostwarO27 said:

I'm working on an old AS984 movement from the 1940's and cannot get the ratchet wheel screw loose.  I've soaked it in numerous solutions  and even tried taping it on my staking set to loosen the crud that is binding the screw to no avail.  I'm starting to strip the screw head and don't want to continue  without reaching out to the forum.

What are my other options?

George

Same issue here a couple of days ago George. As ww  and nickelsilver says, test for the common scenario of a reverse threaded screw. Feel for some movement each way. After a few experiences with them it will become second nature to test and feel for tightening and loosening of a rachet screw regardless of its threaded portion direction of up or down the screw.

  • Like 1
Link to comment
Share on other sites

Yes, checking for LH threads was the first thing I did.  I've yet to come across a movement with LH threads in both the ratchet and crown wheels but I've only been at this a couple years so I;m sure I'll run into one eventually.

I haven't tried the heat but as soon as I'm done typing here, I will be.  I disassembled the movement as far as I could and right now I have the barrel bridged sandwiched  in between the ratchet wheel and barrel arbor and that subassembly is soaking in a ramekin of WD, which as a toolmaker by trade, was our go to solution for loosening corroded nuts and bolts.  The click is still in place to help keep the barrel from spinning when trying to loosen the screw.

 

 

Link to comment
Share on other sites

8 minutes ago, Darthkram said:

AS 984 is definitely a Left Handed ratchet wheel screw.

I made that mistake on the first one I disassembled and wound up with a snapped screw head as a prize!

I just tested a couple other AS 984 movements I have and they were also both LH ratchet screw.

I was starting to think the same thing.  I noticed that the click rotates in a different direction than all the other movmenets I've worked on.  The head of the screw is the same as a RH screw, there is no marking of sorts to alert the mechanic as to the direction of thread.

 

However I still can't budge the thing.  Its like the screw and barrel arbor are one piece.

  • Like 1
Link to comment
Share on other sites

SUCCESS!!

I managed to separate the ratchet screw from the barrel arbor.  I ended up soaking the subassembly in CocaCola overnight and with a couple of taps on my staking set with a punch collinear with the screw axis, it loosened up the crude holding it together.  LH thread.

I'm going to mark that screw head with three lines to indicate to whoever takes it apart in the future that its a lefty.

 

Thanks for the tips y'all !!

  • Like 4
Link to comment
Share on other sites

  • 1 year later...

I'm having the same issue with an AS 1002 movement. However I think the 1002 ratchet screw is RH thread. My conclusion is based on the fact that the click is "standard" not reversed as mentioned above. Also, i can look inside the barrel arbor where the original screw broke off and see right handed threads.

Still i can't get the screw loose on my donor watch. Currently i applied Liquid Wrench, which is similar to Kano Kroil. 

If i want to try heat, can i heat up a "junk" screwdriver with my butane torch and then hold it on the screw?

Link to comment
Share on other sites

You probably haven't given enough time for the oil to penetrate.

Try this.

Remove the balance cock assembly.

Remove balance the jewel on mainplate side.

Remove the fork.

 Drop the rest in Coca Cola for a 48 hrs soak.

Good luck

  • Like 2
Link to comment
Share on other sites

1 hour ago, signcarver said:

I think the 1002 ratchet screw is RH thread.

Be careful. I have just checked on two AS 1002's and in both cases the ratchet wheel arbor screw is LH threaded.

  • Like 2
Link to comment
Share on other sites

Yes, this is common for old AS movenents. The screws, actually, are the same, and can be replaced by each other.  They used only one machine to make the screws, that's for economy.

I can't imagine that the click will work in reverse, that is silly thought. Unless it is on the crown wheel,  not on the ratchet wheel.

Edited by nevenbekriev
  • Like 2
Link to comment
Share on other sites

@Nucejoe Thank you! Soaking now.

@mikepilk Thank you. 

- I have seen the AS 984 and AS 1002 mentioned together as if they are interchangeable but i know the mainplates, ratchet wheels, and crown wheels are different per the pictures below. So, is it possible that the threading on the ratchet wheel screws are different? I'm soaking the donor in Coke so i'll try it again tomorrow.

 - The watch i am working on is marked AS 1002 on the mainplate (see second picture below). Note that both the ratchet wheel and the crown wheel on the original watch are smooth (no circular groove around the screw.)C3141967-88B2-4FBC-8B70-5EE62A5DFE62_1_105_c.thumb.jpeg.21a7136236466e82665e1080fac809f2.jpeg

Mainplate of original watch, clearly marked AS 1002

77E1009F-E0A2-4130-9C32-241E95EBD99D_1_105_c.thumb.jpeg.a2815a802d3b4f3199c1054f20e13dee.jpeg

Donor watch below - The donor watch was advertised as a 1002, but i believe it is a 984 (there are no markings and the mainplate is different from my original watch. 

Note the circular grove around both the ratchet wheel and crown wheel.E75EC251-B3D4-4D7E-98F8-1EB9350C852F_1_105_c.thumb.jpeg.e3f665d05e24d5e26b924c2dc21f3d6e.jpeg

No markings on the mainplate AND the mainplate is different from the original watch.

41C85D85-F6DA-407D-8CFF-64EA62B29BA3_1_105_c.thumb.jpeg.2b341e8283f3f9c60d3195f3c8aae64e.jpeg

 

Link to comment
Share on other sites

Updates:

@Nucejoe Coca Cola soak worked! Got the screw loose. Thank you!

@mikepilk You were right. The ratchet wheel screw and crown screw are both lef handed threads. Also, upon further disassembly of the donor, which i couldn't do until i got the ratchet wheel screw loose, i found a marking on the donor that says AS 1002. It wasn't in the same place as the original, but it was still there. 

  • Like 1
Link to comment
Share on other sites

18 minutes ago, signcarver said:

Updates:

@Nucejoe Coca Cola soak worked! Got the screw loose. Thank you

Popcorn now ?  

Soak balance cock assembly , to loosen two little scrws that hold the upper balance capstone. You be amazed how easy they unscrew.

Edited by Nucejoe
  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • Following on from my question about identifying screws in the AS2063 movement that basically fell out of the case in bits, I’m pleased to report that I’ve got it all back together, and the movement is running pretty well.    But… There’s something wrong with the keyless works and hand setting. It’s fine in winding and quickset date position - these work - but in hand setting position winding the crown turns the whole gear train.  I don’t really understand how it’s meant to work. It doesn’t have a traditional friction fit cannon pinion.  The second wheel is unusual with a pair of smaller pinions on it, which seem to interact with the barrel and the motion works.    Could this be the problem? I must admit I just cleaned it and popped it in place when reassembling the gear train. I’ve lubricated the pivots but didn’t do anything to the extra bits on the second wheel.    Does this make sense and is anyone able to figure out what I’m doing wrong? Thanks in advance, as always.    ETA - the parts list calls it the Great Wheel, not second wheel. 
    • You're thinking metal to jewel in general I guess. Maybe it would be a good idea to peg the pallet staff jewel hole on the main plate after the epilame treatment. I think that could work as it is my impression that the epilame doesn't sit very hard, but I could be wrong about that so feel free to educate me. I didn't remember that 9501 was thixotropic (thanks for the link). That would mean it's even runnier during impact (lower viscosity) so perhaps it's time I get some fresh grease as mine seems a bit too runny. What I have seen is a whitish surface after washing but it goes away if I scrub the surface with a brush in a degreaser (Horosolv). I don't think it embeds itself in the metal but sticks very hard to the metal. I don't worry too much about the cleaning solution. I just want perfectly clean parts and my solution can be replaced for little money (ELMA RED 1:9). Anyway, I quite often need "to strip back and rebuild" and scrubbing parts by hand isn't exactly the most stimulating part of a service. Just got confirmation that Moebius 9501 has a lower viscosity (68 cSt at 20° C) than 9504 (305 cSt at 20°). The viscosity of Molykote DX is 285-315 cSt at -25° to +125° C. I was surprised to see that the viscosity of Moebius 9010 (thin oil!) is higher (150 cSt at 20°) than my 9501 grease!
    • I’ve had a couple movements where it is clear the previous watchmaker was diligent with lubrication but the old epilam had turned to a fine white powder covering the pallet fork and keyless parts, which can’t be good for parts. I’m spare with epi since I don’t know how long it takes to degrade to that state…
    • I have read some suggestions that it can cause wear , particularly on the fork horns of a fully treated pallet fork. I've had half a kilo of steriac acid powder on a shelf for almost a year now, might have a little play today with a heater and a jar.  I think its because it gets into their cleaning solutions Mike. Theirs or anyone else's that services the watch next time, or if they need to strip back and rebuild. Could preclean but thats all time for a pro. I thought the idea was for the epilame to create a barrier, a wall between the lubrication and anything else, so the lube cant spread.
    • As I'm only cleaning watches in small numbers at home, I pre-clean any significant deposits of old grease and oil before using the cleaning solutions. I scrape off deposits with pegwood and Rodico, and if really dirty, wash parts in naphtha with a brush.  So I'm happy using DX, but can understand why it's avoided by the pros.
×
×
  • Create New...