Expert: Martin Meyer - 12/7/2009

Question
Had to replace works after 20+ years.
It went in OK-works great EXCEPT it is losing about 5 mins an hour.I have gone so far as to remove pendulum weight(moving up NG).
Original was #451-0504-94cm
                       __
                       66

Replacement #451-053-66cm.(I don't know where the 66cm vs 94 cm applys but I'm thinking this is a problem??????)

Your help will be much appreciated.
Many Thanks
Bill Smith

Answer
Hi Bill,

Yes, that number is the problem. You have the wrong movement. 94cm is a 94 centimeter long pendulum, and 66 is 66 centimeters. This is a nominal length that Hermle uses, so don't bother measuring the pendulum, it will not be 94cm long. The longer the pendulum, the slower the clock runs, and your pendulum is way too long for that movement.

Also, I think your old movement number was 451-050H-94cm. You MUST replace your old movement with the same movement number. Also, the 053 has a much longer handshaft, so your hands are probably sticking out way too far or you changed the position of the movement on the seatboard. You need a 451-050H-94cm. Don't worry about the other "66" below the line that the movement number is on. That is the pendulum beat rate for use with timing machines.  http://www.clockmasteronline.com