Something is not quite right.

[Shane]

I have been working on a AHO 1121 Automatic on and off for about three weeks.  I have fully disassembled and cleaned it at least three times and I keep getting similar results.  It runs strong and steady in every position except face up.  At first, it would not run in this position what so ever but after adjutiing several things, now it will.  I feel it would run indefinitely but has very low amplitude with somewhat sluggish osilations

There are or have been several idiosyncrasies that seem to be causing or compounding this problem.

The ones that I think that I have improved.

1) The hairspring is more flat and concentric, then it was, with minimal influence from the regulator.  It breaths in a smooth and even manor and is close enough at being in beat as to self start regardless of the direction of first rotation.

2) The uper cap jewel fits into a setting ring and was pushed back in this ring, causing extra end shake in this direction allowing the staff's shoulder to rub and stall on the major part of it's uper setting.  It is now fiting flush with the hole jewel.  But... seems to have very low end shake now.

Things that look off but that I have not addressed.

1) the lower balance jewel seems to be pushed in too deep and is proud of the main plate, possibly causing this lack of end shake.  This may also be responsible for the extreme difficulty in getting the balance to properly engage with the escape lever.

2) The hairspring stud must be installed proud of the balance cock in order to keep the hairspring level, possibly confirming my suspicions of improper lower jewel depthing.  This puts the spring closer to the balance cock from the start, even without the influence of gravity.  Since I was able to see light between the cock and spring, I was convinced that it was not touching while inverted.   (PLEASE SEE PHOTO) I now think the very first coil may be rubbing on the thicker portion of the balance cock causing my problem (very difficult to confirm).

The condition of this watch when I first disassembled suggests that it has been this way for some time and changing it's geometry without thinking about it, isn't something I want to do.

One thing I would like to ask is, should the hairspring remain inside of the detail that I have described/illustrated throughout it's breathing?  And is that the idea behind the jog in coil diameter (as in photo number two)?  If so, I am surprised that I have not found this problem before.

Thank you for your time.

Shane

[Nucejoe]

Hi Shane,

 I think your right, its the upper pivot worn too short, or pivot end is damaged.

 I would take a close look at the upper pivot under good magnification, if worn and is too short, you may need to restaff the balance or replace the oscilator, Needless to say the lower jewel would then need to be move back. 

 Alternatively you can flip the upper end stone to get the domed side of end stone face the pivot.

Make sure hairspring collet is pushed all the way down to collet seat.

Regs 

 

[Shane]

Nucejoe,

Thanks for your friendly reply.

Good idea on the spring collet but I had the spring of and back on twice before and I'm reasonably sure it was bottomed out.

Unfortunately, I will have to restart pretty much from scratch.  I slipped last night while loosening the balance screw snaping off one the pivos.  Frustrated, I moved to an AS 1803 and a Brac 501.  Both of which have been set aside until I needed to pull out my staking set.  The 1803 and it's offset cannon pinion had been previous discussed on this forum and is now reaffixed and reinstalled.  As for the offending AHO 1121, my abilities to restaff a balance can always use more practice.  My Otero 48 has been running smoothly for several days but without the date and automatic parts installed.

Shane