Hi all,
Can you identify the items listed A, B, and C.
Thanks
jim

 

A is the regulator
B is the stud support

C looks to be a sort of indicator with adjusting screwhead that is cam shaped. Turning the slotted head moves the regulator arm in tiny increments. Don't know the exact term since these are uncommon, relatively few watch movements have these.

 

A is the stud to which the end of the balance spring is fixed, called the "hairspring collet" in the manual TM 9-1575.
B is the rotor used to wind the movement by your motion, unless you meant the regulator pins, where the balance spring passes through as a functional "end point" for the balance spring, and whose position determines the rate.
C is the regulator. In the 1120 movement, that screw has an offset head and turning it moves the regulator a tiny amount so the rate can be adjusted.

 

This image shows the parts in question more clearly.
I may be wrong but from what I can see of the hair spring it looks like the brass colored part holds the regulator pins and the darker part is the stud support.

 

Yes, you’re right, I had them reversed.

 

The reason I ask. My 1120 is running about -9sec a day. From what I understand, "C" is the micro adjustment for the rate and each +/- notch equals approx 5 seconds. So, turning "C" about two notchs should bring the watch into about +1 sec a day. Am I about right?

 

If it hasn't been serviced lately, that's likely what it needs.

 

There is no set amount that each "notch" corresponds to, but other than that, have at it.

 

I've never had much luck with regulator calculations. Trial-and-error works best. Move it a little and re-check the timing.

 

Ive updated the pic so its easier to see what Im talking about. Thx

 

If you notice, "C" I believe is the micro adjustment to the speed of the movement. However, I believe that it is not round, but in the shape of an oval, allowing minute changes to be made to the regulator "A". So, "D" must be attached to "A" via friction, allowing it to move "A", but also to allow "A" to be moved independently. One of my thoughts is, Before any adjustments be made, would it be wise to center "C" so that when the final adjustment with "A" is complete, you have travel room to adjust "C". My next question is, does the little groove on "C" need to be facing so that the opening of the slot face to or away from balance spring, or does it matter

 

The fine adjust is an eccentric, rather than oval. Based on your questions, I would avoid touching A, B, or E, and just stick to turning C.

 

I've found that every set of notches similar to this can advance or retard by minutes rather than seconds. Of course none of my watches has this sort of micro adjustment.
I've also read complaints of other sorts of micro adjustments saying that the indicators are way off.
I've found that regardless of indicators its best to advance or retard in near imperceptible increments.