992B question (Updated!)

February 19, 2015, 11:06

Dana Fuller

Recently acquired a 1952 (same year as I am) 992B and had it serviced. After carrying it for a week, it seems to be gaining about 15 seconds a day. Is this acceptable or can it be improved on?

February 19, 2015, 12:20

Paul D. Trombley

A 992B should be able to keep time within seconds per week.

There is a fine line between servicing a watch (make it run) and timing a watch. I'd at least call my guy and ask him if he can revisit the watch to bring it up to speed.

Most RR's will come in to time with a good service. If it is consistently fast or slow and has consistent numbers in the various positions... it is generally pretty easy to fine tune the watch and bring her back to specification.

If the watch has erratic beat error or the timing is grossly fast/slow or the watch can't figure out from one position to another if it wants to be fast or slow... then, something else is going on that is often outside the scope of the base line COA. It could be a cracked or sloppy hair spring collet, a cracked jewel (anywhere in the train - this generally shows up as a watch that runs great in 5 of 6 positions but lags in only one position)., a loose roller or pallet jewel (which show up on my machine as erratic beat error caused by the inconsistent impulse and extra noise that confuses my timing machine).

Then you get in to weird stuff like, hair spring dragging on a balance arm only in the face up position... or a timing screw out too far that drags on the inside of the balance cock only in the three o'clock position, or an end play issue that allows the balance arm to drag on the balance cock in the face up position... or a piece of lint caught in two coils of the hair spring that cause to coils to sister up and act as one, making the watch inexplicably fast... and not always consistently fast.

So, with all that said, it is a matter of pride and professionalism for most of us to bring a watch in to beat and time if it is naturally capable and otherwise expected to perform at that level. Minor hair spring issues, polishing or dressing up pivots, securing roller jewels, tightening collets, adding a weight washer to poise the balance, minor balance wheel alignment are addressed as part of the COA.

Much outside that gets in to additional repair work and is quoted separately.

Then again, most of what I've discussed here is more about bringing a watch back to specification. Timing an adjusted watch to make it a 5 position watch is a whole nother matter that far exceeds my understanding and abilities as a novice watch maker. Polishing pivots, selecting jewels, depthing... to make it run at that level.

I would ask him to revisit the watch and bring it in to specification... or have him explain if there is a material issue that prevents him from doing this.

February 19, 2015, 13:57

David Abbe

15 seconds a day means at a minimum the watch needs re adjustment. Sadly that deviation would make me very suspicious of the quality of service in the first place. So not knowing who you had do the work makes the decision on how to correct the issue your call.

February 19, 2015, 16:56

Dana Fuller

Could the adjustment be made at the regulator screw? I understand that a full turn can yield a 20 +/- 2 second change per day.

February 19, 2015, 17:30

Paul D. Trombley

Of course it can, to some extent. Some models respond brilliantly to a twist of this screw, some models will hardly respond at all.

20 seconds is typically the full range of the needle on the scale. This is meant to be a fine tune adjustment to make up a couple seconds a day.

An adjustment of 15 seconds a day is generally done at the balance wheel.

February 19, 2015, 18:51

Lindell V. Riddle

Dana,

I urge you to do this and ONLY this as a first step...

Set your adjustment on dead-center which is where it SHOULD be after service. Rotate the watch back and forth to get the balance wheel moving and gently wind the watch. The balance wheel should oscillate in an even arc. It is possible the hairspring is slightly tangled or has some dirt or oil on it. Look carefully with your loupe while the watch is running to see if anything might be amiss.

Now time the watch. Properly serviced 992B will be beat-for-beat with the atomic clock such as the big yellow clock in our IHC Auctions day after day or very close to it. Sometimes a newly serviced watch will run a little fast the first few days and then "settle-in" to normal timekeeping. Particularly true when the mainspring has been recently replaced.

SUGGESTIONS :

DO NOT change or readjust anything other than being certain the basic adjustment is on dead center, half-way on the scale.

DO NOT carry the watch, but rather set it upright and wind at the same time each day for 5 days and record any variation each day.

If it is off by much more than 15 seconds plus or minus at the end of 5 days (Railroad Standard Timekeeping is no more 30 seconds variation in ten days.) you might consider sending the watch and a copy of this topic back to the person who worked on it. If it is "settling-in" or if it is way off continue charting it for a full 10 days during which the variation plus or minus should not exceed 30 seconds if all is well. Chart your timing carefully so you have an actual written performance report to show and a factual basis to use if in fact you have a complaint.

Recently I went through a 992B from my birth-year set it upright on a lucite stand, wound it around noon each day for 5 days and found no variation, that is how every 992B was built to run.

(If the watch was a non-Elinvar it would be wise to de-magnetize and that still is not a bad idea.)

Like suggested by Dave Abbe in his post above, I too would question whether the watch was properly serviced if you still encounter such a radical variation from normal as you originally reported.

We have several good sources for service within IHC and I recommend them highly.

Just for fun, follow these timing suggestions and report back how it goes.

Lindell

February 20, 2015, 09:15

Dana Fuller

Thank you, gentlemen. As always, a lot of good information to be gathered from this site. I'm curious to follow Lindell's procedure and see what happens.

March 17, 2015, 08:55

Dana Fuller

992B update

Followed Lindell's advice and set the adjustment to dead center which required about 1 full turn of the screw. Then set it against an atomic clock for 5 days. It couldn't have varied more than 2 seconds over that period. Started carrying it again and it has remained dead on target. Amazing timekeeper.

March 17, 2015, 10:36

Mark Cross

Sounds like it just needed to settle into a routine.

Enjoy your 992B!

Regards! Mark