7750 Cross threaded setting lever screw

[AP1875]

Servicing a Chinese 7750 for a friend and one of the screws for the setting lever jumper is cross threaded, preventing me from removing the keyless works? 

Does anyone have any tips on how to remove a cross threaded screw? 

Will I have to tap a new thread if I remove it? The thought of doing that on a tiny thread like this is daunting 

[Nucejoe]

See if lets the cover plate turn aside. If so, all other screws should be removed.

 

[AP1875]

1 minute ago, Nucejoe said:

See if lets the cover plate turn aside. If so, all other screws should be removed.

 

sorry, i don't understand your post

[Nucejoe]

Remove all other screws, leave the bad screw alone, turn set cover plate in anti-clock, turn it aside while attached, with the screw in its hole. 

 

[Nucejoe]

Turn the cover aside out of the way, so to access the set jumped.

[Nucejoe]

Turn the cover aside out of the way, so to access the set jumped.

[Nucejoe]

Turn the plate around the screw.if it lets this.

Edited May 4, 2019 by Nucejoe
Turn about the screw.

[AP1875]

there are only 2 screws in the setting lever, 1 has been removed the other keeps turning without retracting due to being cross threaded. You can't move the setting lever (plate) until the screws are removed. Not quite understanding what you're saying. 

[AP1875]

12 minutes ago, Nucejoe said:

Turn the plate around the screw.if it lets this.

the plate would just be spinning around the screw which is stuck in the thread?

[AP1875]

[HSL]

lol must say I was a little bit confused there for a while but now I see the jumper lever actually looks like one from the 7750..
Guess you have to remove the good screw and unscrew the bad one as much as it goes, try to do this with sharp edged pliars.
 

[AP1875]

6 minutes ago, HSL said:

lol must say I was a little bit confused there for a while but now I see the jumper lever actually looks like one from the 7750..
Guess you have to remove the good screw and unscrew the bad one as much as it goes, try to do this with sharp edged pliars.
 

You and me both haha. I unscrew it and it loosens off a thread or two. At this point i either commit to removing it and grip it with something or screw it back down and tell him his swiss cheese chinese screw is stuck, so i can't clean and lubricate the keyless.

If i do remove it, i risk stripping the thread in the plate. What would be the process, should that occur?

[HSL]

1 minute ago, AP1875 said:

screw it back down and tell him his swiss cheese chinese screw is stuck, so i can't clean and lubricate the keyless.

I would think this is the best solution..   You could lubricate what you reach since there will probably not be non from the begining..

[AP1875]

Just now, HSL said:

I would think this is the best solution..   You could lubricate what you reach since there will probably not be non from the begining..

oh ok. From inspection the movement is actually pretty clean but there is no sign of lubrication as you suspect.

Just out of interest, if this was a valuable movement that required a service and someone had cross threaded this screw during the last service. What would you guys do?

[HSL]

I have doubts that a genuine 7750 would be able to get crossthread, but if it was i would have put in in my lathe and drilled out the screw as long as it had the head left.. 

[AP1875]

2 minutes ago, HSL said:

I have doubts that a genuine 7750 would be able to get crossthread, but if it was i would have put in in my lathe and drilled out the screw as long as it had the head left.. 

how would you get the screw head in the centre of the lathe? I could try this, we have lots of lathes of different sizes in work.

[HSL]

A little bit hard to descibe the tool but you attache a pice holder with three adjustable gripers , theese allow you to set a workpiece excentric to the backstock..
Ahh ..a video is better, around 3:35 you can see it in action..

 

[AP1875]

13 minutes ago, HSL said:

A little bit hard to descibe the tool but you attache a pice holder with three adjustable gripers , theese allow you to set a workpiece excentric to the backstock..
Ahh ..a video is better, around 3:35 you can see it in action..

 

Thanks for showing me. Unfortunately I dont have access to that setup

[2131tom]

Apologies if you have, but have you tried putting a small stiff strip of metal (or a flat bladed screwdriver) under the setting lever (plate) as close to the cross-threaded screw as you can, and then gently applying a constant pressure to lift the plate upwards, as you turn the screw to unscrew it?

I've often found that re-engages the screw and thread and allows the former to be removed.

[Nucejoe]

No need to remove the screw and the cover plate, just to gain access to the keyless.

If this was an expensive piece expected to tic for a generation or two, one would think of repeatability in cover removal, only then repair of the crossed thread makes sense, repair lathe work etc costs more than a new clone movement.

If you must access the set mech, remove the screw not marked in the pic, this will let turning the cover plate about the bad screw just so to get it out of the way and let you access the keyless, @2131tom explains how.

[CaptCalvin]

Sounds like stripped rather than crossthreaded. You can try sticking a needle or something in the same screw hole from the other side of the plate and apply pressure to the bottom of the screw as you unscrew.

5 hours ago, HSL said:

I have doubts that a genuine 7750 would be able to get crossthread, but if it was i would have put in in my lathe and drilled out the screw as long as it had the head left.. 

Genuine ETA's aren't immune to defects. I had one 7750 that came with hairspring that had like a 10 degree slant, and another one with a loose screw bushing for the chrono seconds brake. Both were brand new genuine ETA.