Adjusting the Speed – Howard Miller Mantel Clock

Open the door on the back of the mantel clock and look inside toward the top right of the brass movement. You should see a silver “arm” coming out of a clear box in this area. This part is called “the platform escapement”. This is the main time keeping part of the clock.
(**before continuing, make sure your clock is fully wound on all three winding areas.**)

Correcting the Time - Howard Miller Mantel Clock

Adjusting the Time – Howard Miller Mantel Clock Move the lever up or down to adjust time. Make small, very small adjustments until it is correct.

Changing the speed of time keeping is accomplished by ever so slightly moving the time adjustment lever. (See figure 1). To slow the clock, move the lever down towards the “-” (minus). To speed the clock up, move the lever up towards the “+” (plus). A small change will make a quantum change in the speed of the clock.

Check the clock 24 hours later and make another slight change in the arm up or down and continue as needed until the clock is keeping good time. Once this is set, you should not ever need to change it for many years.

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  1. Posted February 16, 2015 at 12:19 am | Permalink

    I have an older Howard Miller mantle made in W. Germany. There is no time adjustment lever as shown, but the back plate shows ” – +”. The rotating wheel is set horizontally in the window rather than vertically as shown. Where is an adjustment lever or how does one adjust this model?
    Thanks for your help.

  2. Grandfather Clocks
    Posted February 27, 2015 at 8:23 pm | Permalink

    Some older Howard Miller mantel clocks used Hermle movements which are different from the Kieninger movements found on the newer clocks. The Hermle movements have a nickel plated screw with a slotted end pointing straight toward the back. This should be near the location of the – / + marking you indicated. You should be able to turn the screw slightly to make an adjustment in the direction needed as on the marking in the brass. Never move it more than 1/8 turn / day. Make a correction after setting the clock to the exact time including seconds and check it again a day later. Repeat with smaller increments of the turn until the time is correct.

    Good Luck,

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