....have a complete and what should be a running Illinois 18S Model 6 movement...have power to the pallet fork...the jewels are in good condition as are the balance and staff...the hairspring while it is concentric, clean and hooked up, 'droops' about an inch when held suspended by the balance cock..is is too tired or fatiqued?...thanks...Jim C

The amount a hairspring "droops" when the complete balance is suspended from it, shouldn't be a factor in preventing a watch from running.

The necessary strength of the hairspring is determined by the moment of inertia of the balance, and the correct beat count of the movement (most pocket watches are 18,000 beat).

If your watch fails to run at all, it's a safe bet that the strength of the hairspring isn't the problem. If it runs, but fails to rate by a significant amount, then the hairspring could be incorrect, but that isn't very likely.

To determine the actual cause of failure to run (in the present situation), operate the pallet manually from side to side, and see if the escapement advances as it should. Use Mr. Thissell's advice to check the "locks," "drops," "slide," etc., and make sure all of that is within reason.

Next, if you're already sure the watch won't run with the balance installed, see how the balance does installed by itself, without the pallet. A tiny "puff" of air or a "flick" of the wrist should start it oscillating, and its movement should be entirely free. If it doesn't continue in motion for several seconds, it's very likely that the staff is binding in the hole jewels, or that there's insufficient endshake for the staff between the cap jewels. Obviously, the correct course of action depends on the problem, but will have to result in more freedom for the staff.

If the balance moves freely on its own, as does the pallet fork and escapement, but the movement fails to operate when assembled, there's a problem in the interaction between the balance and the pallet. Check things such as roller jewel size, guard pin interaction and height, banking pin adjustment, etc. Whatever it is, it should be relatively obvious once you've determined exactly where to look.

In this particular case, I'm going to bet on insufficient balance or pallet endshake, but that's obviously just an "educated" guess.

As always, I hope this helps, and will be looking forward to hearing how things turn out!

=====================

Steve Maddox
President, NAWCC Chapter #62
North Little Rock, Arkansas
IHC Charter Member 49

...thanks Steve so much!...well I proceeded as per your checklist and concentrated first on the pallet lever...in the course of that examination, I discovered that one of the very 'tips' of the pallet fork had broken off and was, under magnification, decidely shorter than the other to the extent that the 'toe' was missing from the leg
as it were...also, the roller jewel had quite a bit of wear on the face which may have been caused by the broken foot on the fork...would this, as I suspect, be the issue?...thanks again, Jim