Howard Miller - Mantel clock time adjustment?

Posted: Tue Mar 23, 2010 1:00 pm     Post subject: Howard Miller - Mantel clock time adjustment?

I have a Howard Miller Mantel clock. From the HM site it looks like the 612-437 Graham Bracket model, but the number on my clocks movement is 340-020.

The manual for the 612-437 shows a different time adjustment picture than what mine looks like. Anyone know how to adjust time on a HM movement #340-020?

Posted: Wed Mar 24, 2010 6:59 pm     Post subject:

The 340-020 model number actually pertains to the movement (which is manufactured by Hermle - I believe). Howard Miller does not make the movements. The 340-020 should be equivalent to our #13006. On current models, there should be an adjusting screw located around the balance spring and balance wheel (top rear of the movement). It should have a "+" and "-" indication etched on the plate nearby. One full turn of this screw is equal to about 60-80 seconds in a 24 hour period. If the clock is losing time, turn the screw in the "+" direction. If the clock is gaining time, turn the screw in the "-" direction. Always allow the clock to operate a full 24 hours before making another adjustment. After 24 hours, see if the clock has gained or lost time, and adjust again if the need should be. It is my understanding that older movement models may have something different than the adjusting screw, but I am not familiar with what it is.