AS 175 ratchet wheel left or right hand screw?

[luiazazrambo]

Hi *,

I need some advise, I am servicing my misses wrist watch, which has an AS 175 movement. I have already broke off a pin and now I cannot remove the screw of the ratchet wheel. I treated this screw as right handed so far but did not move. I consider myself lucky that I did not brake the head off so far because i used some force. Please note that the "crown wheel" is only decoration. So is it a normal or a left handed screw?

17jewels AS-175

 

Take care,

lui

[JohnR725]

90 some percent of the time that screw is left-handed. The way that you can tell is that when your winding the watch if it was a right-handed screw it would have the possibility of unwinding the screw which would be bad. As they made it so screw goes in the opposite direction of the wheel turning and it will not accidentally unscrew.

On some newer watches they will put additional lines with the screwdriver slot to indicate that it's a left-handed screw but that's not super common.

You might have to put penetrating oil on the screw head to get it to loosen up if you've tightened its super super tight. Or if it was frozen in the first place penetrating oil helps to. I had this happen yesterday with the Illinois pocket watch I was 99% sure of the direction and it required a heck of a lot of force to unscrew left-handed of course. I'm assuming somebody pre-tightened it for me which is common people do that like you have. Then yes there is a danger of breaking the head off now.

[luiazazrambo]

Hi John, thank you for the quick answer. I have already put some penetrating oil on it a few hours ago. Let me see if it helped, i go to the other direction now.  I update this post about the result.

[nickelsilver]

On AS it's a toss up. Try it both ways. A tip- on a thread that you're sure is right hand but seems stuck, tighten it, then loosen; works great. So in that vein you can't really go wrong here.

[Nucejoe]

Penetrating oil will not get to the screw thread,  a 48hr soak in cocacola loosens rust,  unless somebody has put loctite on the thread in which case heat the screw with solder gun.

[JohnR725]

14 minutes ago, Nucejoe said:

Penetrating oil will not get to the screw thread

It may depend upon the penetrating oil. Yes if you have super tight metal on metal contact nothings going to get there.

At work we have the stuff found at the link below. Notice in the description what it says it's used for and what it does? Is not for Rusty screws it's where screws that are super super tight.

 

https://westernoptical.com/products/screw-loosening-fluid

[luiazazrambo]

Left handed. Seems that the penetrating oil found its way probably even to the thread, or found its way when I actually removed the screw we will never know. Just to make it sure I do everything I can I heated the screw head up with my soldering iron.

Thank you good ppl of WRT.