Expert: Michael Radi - 4/3/2009

Question
I have 3 clocks (Hermle works) which have the little screw for adjusting the time at the top right of the clock works.  I recently purchased a Seth Thomas clock (Legacy - German works - 1980's) which has the plus and minus for adjusting the time on the brass plate covering the back of the works.  The plus and minus are to the right and left of the hole for the flywheel.  There is no little screw at the top right of the works to adjust.  Does anyone know how to adjust the time on this particular works?  Thanks!




























































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) which have the adjustment screw in the back at the top right of the works.  The Seth Thomas legacy clock (made in Germany for Seth Thomas in the '80's?) has the "+" and "-" on the brass back of the clock on either side of the hole where the flywheel is.  This works does NOT have the little screw at the top right of the works, so I have no idea what I am to adjust to correct the time. I  purchased the clock on ebay so have no directions.  Can anyone help??   Thanks!

Answer
There are two different styles of floating balances that Hermle used on their clock movements: The old style has what I call a worm spring to suspend the balance, allow it to swing and provide the tension to stop and push it the other direction. This style of floating balance is adjusted by turning the pronged section on top of the wheel. You hold the wheel at the outside of its diameter and push the prongs in the direction that you desire: toward the - to slow it down or toward the + to speed it up.
Several years ago, Hermle introduced the newer style floating balance with a coil hairspring. This is interchangeable with the old balance. Meaning either style should fit any of the movements that use a floating balance. The new style is easier to adjust. There is a silver colored threaded post with a screw slot on the back end. When you turn the screw, a finger riding on top of the threads moves along the threaded portion. This moves the slot that the hairspring runs through thus adjusting the timekeeping the same way a mechanical watch is adjusted. There is a + and a - telling you what direction to turn the screw for the desired action.
Michael
www.norkro.com
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