To get the parts necessary to achieve the best fit, you often have to choose among a variety of “closest fit” options. For example, if the hand shaft is too long, it’s common to “shim” clock movement back into a case with a few washers over the hand shaft. It’s also common and acceptable to trim the replacement hands as necessary to shorter lengths to ensure a good match with the clock face.
You are going to have to take a couple of simple measurements.
It’s not that hard to do. Just do not assume that anything is standardized in the clock parts business, which could get you into trouble. The exact same movement or insert may no longer be available from 10 or 20 years ago.
It’s also a “myth” that there is some cross-referencing guide we can refer to match old movements and inserts to contemporary ones.
First, let’s define what it is you are looking for. It’s normally a clock movement, or clock motor, but it also could be a self contained clock module called an insert clock or fit-up. A clock movement or motor is defined by its size and functions.
Some movements are time only, some have pendulums, and some have chimes.
What features does yours have? What features would you like? This is step one. Let’s see, you have a movement with no pendulum, but it has a Westminster chime that you would like to keep.
Perhaps you have a wall clock that is very large and your minute hand is over a foot long.
Use a short sentence to define what functions your clock movement actually has. You can go to www.clockparts .com or our catalog and look specifically at just different types of clock movements grouped together by function. The most important measurement on a battery or electric clock movement is the length of the hand shaft. Every analog clock movement has a shaft sticking out of the “little black box” that holds the clock hands.
You need to measure the hand shaft from the movement to the very end. This is called the overall shaft length The other important shaft length is the length of the threaded part of the shaft. This threaded shaft holds the washer and hex nut that actually attaches the movement into the clock case. The length of this part of the hand shaft determines how thick the material is that the hand shaft can actually go through. It can vary.
Once you know what your overall shaft length is, and either the length of the threaded shaft, or the thickness of the material it goes through, you are ready to start looking for clock movements, or motors, with confidence.
Let’s say that you have a large 3 foot diameter wall clock with hands over a foot long. You know the threaded part of the hand shaft is just under ½ an inch, and your clock face is ¼ of a inch thick.
You need to look at high torque movements that will work with a dial thickness ¼ of an inch or over.
If you have trouble taking this thickness measurement, then stick a pencil through the hole, mark each side, then remove and measure the distance between the marks. You need to have a threaded shaft length that is 1/16 to 1/8 of an inch longer than the thickness of your clock dial. Pay attention to the overall shaft length if you clock has a lens, or crystal. You do not want the hands to be able to hit the lens.
Between knowing the length of the threaded part of the shaft you need and knowing the overall shaft length, you are ready to start considering clock movements, or motors. Please remember that if the hand shaft we are offering is too long, it can normally be “shimmed” backwards with a couple of washers. If it turns out that you are looking for a fully assembled insert clock, then take a look at our new article Learn How To Choose The Right Insert Clock, or fit-up for repair. I’m Mike Brosman for www.clockparts.com.
Hopefully viewing this will make it easier for you To Choose The Best Repair Parts for your project.