When a Copal motor gearbox fails, it’s usually either the first or the last gear in the series.
The last gear has a steel shaft with a spline on one end going through it that tends to split the plastic. The wall thickness on the upper portion of the gear is very thin. Over time and use it gets brittle. Several clock motors I have repaired have either failed or have a crack on this gear. I have been looking for a solution/ fix for a long time.
Finally the fix came from, of all thing, the handle of a frozen desert called a “push-up”. I buy them for my grandkids when they visit. They are a handheld cylinder of sherbet ice cream that pushes up with the handle.
The inside diameter of the handle is (3mm) The handle wall thickness is perfect and provides clearance for the matting gear. Cut to about 5mm in length, it has a nice snug fit. This closes the crack and holds really well. It acts as a ridged sleeve. I add a small amount of super glue to hold it in place. The shaft now fit tightly and will not slip. I had to make a simple spacer tool to press the shaft back into the repaired gear to set the height and alignment to the matting gear.
I don’t know what tolerance these push-up handles or the gear hold. The ones I have used them on so far fit very well and appear to be a solid repair. Next is to find a solution for the first gear. Unfortunately that one usually starts to breakdown and loose all its teeth.
.
The last gear has a steel shaft with a spline on one end going through it that tends to split the plastic. The wall thickness on the upper portion of the gear is very thin. Over time and use it gets brittle. Several clock motors I have repaired have either failed or have a crack on this gear. I have been looking for a solution/ fix for a long time.
Finally the fix came from, of all thing, the handle of a frozen desert called a “push-up”. I buy them for my grandkids when they visit. They are a handheld cylinder of sherbet ice cream that pushes up with the handle.
The inside diameter of the handle is (3mm) The handle wall thickness is perfect and provides clearance for the matting gear. Cut to about 5mm in length, it has a nice snug fit. This closes the crack and holds really well. It acts as a ridged sleeve. I add a small amount of super glue to hold it in place. The shaft now fit tightly and will not slip. I had to make a simple spacer tool to press the shaft back into the repaired gear to set the height and alignment to the matting gear.
I don’t know what tolerance these push-up handles or the gear hold. The ones I have used them on so far fit very well and appear to be a solid repair. Next is to find a solution for the first gear. Unfortunately that one usually starts to breakdown and loose all its teeth.
.
Comment