Reply To: Runaway waltham

[Bob Tascione]

Good to see you up here Ozanam!
Very happy to hear that the course is working out for you.

I wanted to ask you if you’re running fast in different positions ie; dial up, dial down and pendant up. Also does the motion drop off much when changing positions? Knowing this may help diagnose the problem. Checking for magnetism first was a good call. Yes a dirty or sticky hairspring can cause a watch to run that fast. Also if the new hairspring is out of flat the coils may be touching something like the balance arm or out of round (having to stretch to pass between the index pins) then they may be touching each other during balance occilation. The hairspring should fall between the index pins naturally. That is you shouldn’t have to pull the hairspring over for it to fit between the pins.
Those are a few the things you may want to check first. I’ve added more below to give you an idea of what else may be occuring. We can go deeper into this if need be but please try checking the stuff above first.
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Although you can sometimes get lucky after putting a new old stock hairspring on a balance that was made for a Waltham movement often times you’ll find that it can’t be brought into time with the regulator alone. The reason for this is that the mass of one balance rarely equals exactly the mass of another. Even at the factory. For this reason the hairspring is matched to the balance at the factory by “vibrating” the balance with hairspring attached. The hairspring is held in different places until its rate matches the vibrations of a master balance which beats the exactly the desired number of vibrations . This will insure that the hairspring is cut to the correct length while allowing a little extra for pinning to the collet and stud. This may sound difficult because it really is. In fact most watch repairers these days don’t know the process or may understand the process and theory but have had little or no practice vibrating hairsprings. It takes a great deal of practice to become proficient at it.. Ok so now what? Well with newer watches most watch repairers will buy a “balance complete”. This is a nicely packaged balance assembly with roller table, roller, and vibrated hairspring ready to be dropped into a movement. Nice and quick. Finding a balance complete for older watches can be much more difficult. Often times people have old spare “parts” movements to salvage parts and balance assemblies from. Also there’s ongoing debate that changing out the balance from a watch like your Waltham takes away from its original condition, devaluing the timepiece. You may notice some engraving on your balance arm. This is how you can tell if it’s original to the movement. Fortunately many of these NOS hairsprings can get you close enough to adjust your way to acceptable timing by adjusting regulator screws on the balance rim at the ends of the arms or by adding or subtracting weight to the balance. Ideally the regulator should fall halfway between its fast and slow limit. This can usually be accomplished if the rate isn’t too far off. One hour a day is quite a bit though.
Hope this helps Ozanam, ENJOY
Bob