Hamilton 992. Is the ratchet wheel screw right or left hand thread?
Thanks,

Aaron Bereiter
NAWCC# 156432
Very Proud IHC Charter #55
We rise highest when we stoop to help others.

Hey,I just happened to have one of mine apart to replace a mainspring,checked it and it's left handed.(sn/2373442)

Aaron,

I have always considered a theaded fastener of any kind that required you to turn it clockwise when tightening, to be right handed. Am I wrong?I would call the screw on the RATCHET wheel to be right handed. The one on the CROWN wheel should be left handed. It is usually turned counter-clockwise to tighten. You are referring to the ratchet wheel and not the crown wheel, I trust? Did an American maker ever mark a left handed screw the way the Swiss do? On the older 992 with two screws holding the crown wheel core, the screws turn clockwise to tighten so I would call those right-handed screws. This is usually true with any crown wheel core held with two screws.

By the way. I am anticipating the first time you do a watch which has the crown wheel UNDER the bridge, rather than on top (Longines for example, and some Le Coultres as I recall). With an underslung crown wheel, the screw is RIGHT handed, not LEFT handed.

Doug S.

Sorry, Aaron,went stupid.Nevermind.Doug's absolutely right.

Thanks guys, Elgins have left hannded threads on the crown wheel but not the ratchet. My 992 has two screws on the crown wheel retainer but only one on the ratchet wheel. It is prety tight and I didnt want to break it off. How is this watch to work on? All I have done is a bunch of 16s Elgins and one 18s Elgin 3/4 plate. All with sucess and no marks. Any advice would be appreciated. Thanks,

Aaron Bereiter
NAWCC# 156432
Very Proud IHC Charter #55
We rise highest when we stoop to help others.

In case it helps anyone, I remember it because I reasoned that a left hand screw is necessary on crown wheels because the wheel turns to the left and would have a tendency to loosen a normal, right hand thread screw. It doesn’t hold true on crown wheels with two screws because it is the washer under the screws that interacts with the crown wheel.

Bruce Aldo