We all now joke about "personal magnetism" that prevents watches from performing properly.  This kind of myth was invented to justify poor workmanship and get a customer to stop complaining. 

Then there are the myths like "overwinding".

 When a timepiece stops working, what is the first thing someone does?  Wind it up of course!  But if it failed because of dried out lubrication or worn pivot holes, winding does nothing.  Then the next person discovers it is fully wound and does not work; must be overwound.  Many a child or partner has been wrongly accused when int fact someone HAS to be the last person to wind a timepiece that has failed due to maintenance issues.

The only true cases of overwinding I have encountered related to people using vice grips on vintage Swiss aircraft clocks which wind in reverse of normal and have no clutch.  Unless the stem or winding wheel are broken, it is hard to make a case for "overwinding".

Here are my thoughts on what I have now come to see as myths for watchmakers.  These are practices every author from Fired to Jendristki have described; and only Jendritski makes it clear that they apply to NEW work (Jendritski's Watch Adjusting).  But many authors have described these practices in the context of watch service.

Once I thought it through, I came to the conclusion these practices really have no or very limited use in watch servicing.

Poising.  Almost every watchmaking tome encourages the reader to "poise the balance" with the poising tool. This practice is only useful when doing new work.  Countless precision watches have been destroyed by people who took this as fact from writers such as Fried.  They either used balance wheel undercutters, filed the underside of the screw heads or turned the heads down in the lathe to do a first class botch job.

Totally unnecessary and destructive in repair/restoration work.  

Think about a Hamilton 992 Railroad watch that never was sold and is still in its original factory sealed container.  It is out there somewhere.  Yes, the balance was poised when first staffed.  But then, it was "adjusted to 6 positional rates".  This was done by timing the watch in the positions and then moving  or changing the balance rim screws.  By definition, the balance left the factory "out of poise"; but adjusted to hold 5 seconds per day across 6 positions!

So now the staff in that watch needs to be replaced.  First, the roller determines everything and in fact it can only go in one of two positions by convention.  In 2 arm balances, the impulse jewel is set to be perpendicular to the arms.  There are only two locations.  If you are smart, you will mark the original position with ink.  Even still, if the timing is off when done, you only need to rotate the roller 180 degrees.

Ok.  You DO need calipers to level and true the balance in the round (under minimum 10X magnification); but if you did your job properly, the corrections should be minor.  Just do not handle the balance like a sack of potatoes.

Now you do what Hamilton did; and what today is called is dynamic poising.  You set the balance to a specific amplitude and measure the rates in 8 vertical positions to determine the heavy spot on the balance rim.  Before you touch anything though, if the timing results indicate the roller position is involved, rotate the roller and retest.

With dynamic poising, you do not need to bother with the poising and the use of the tool will lead to undo factory determined distributions of mass.

If I had a balance assembly that was badly vandalized, I could start possibly use the poising tool to give me a starting point.  But for reasons of physics (look up "Q" and resonance of oscillators), if the balanced is that badly damaged, I would look for a donor balance assembly.

Think about it, all those authors stated the use of the poising tool as an article of faith without ever explaining why in the world anything done in restaffing would change the factory adjustments; other than poor technique.

Fitting a new balance spring.  This is another myth promoted by many authors and the popularity of "hairspring fitting services" in the old days.  And it makes it very difficult to find a railroad watch with a true oscillator.

When a watch is designed, the geometry of the balance spring is actually determined by trial and error.  When a good pattern is found, the angular positions of the bends are measured and recorded and the balance springers are trained in how to produce that design.  Tony Simonin told us at Wostep that when he first started working, it took him 3 months to produce one good spring; and that was for one caliber!  He had the pattern to follow.

In class, we spent a month producing two springs for a Rolex balance for a grade.  Again, we had the specs to follow.

When I came home, I sold my set of grade balance springs and my balance spring vibrating tool.  I had learned that it is impossible to produce a spring that will result in precision timing (less than 10 seconds per day error across all positions) unless you KNEW the pattern for that caliber!  And then it took an unrealistic amount of practice to make that spring.

A watch is not a watch just because it ticks!  It must function as intended.  And most watches worth servicing were intended to be precision instruments.

Which brings us back to to balance spring vibrating services.  You sent the balance and they would send back a balance with a vibrated spring to keep time.  But unless the bends were made in the factory specified positions, it was extremely difficult if not impossible to return it to positional performance.