I'm building a custom clock that requires 4-5 clock hands that need to move individually. I've designed it so the hand are to be mounted on telescoping brass axles (that have press fit gears individually connected to servos on the back). There's very little clearance on the front of the clock, so axle only has ~4mm of space on the front.

Right now, I've 3d printed clock hands from PLA and press fit them onto the brass axles. This works, but requires a bunch of fiddling - the PLA tends to warp and require manual bending back into shape so it doesn't bump into adjacent hands. The press fit also has a tendency to slip sometimes.

Is there a better way to design this? The hands ideally would be removable, though it's OK if that process takes some time as it doesn't happen often.

I have access to a 3d printer, a laser cutter, and a variety of woodworking equipment. If there's an excellent solution that requires more equipment, I may be able to get access.


1 Answer 1


The question is vague enough as to be at risk for closing, but I'll toss one suggestion your way.

If you look at a conventional clock assembly, you'll note that the (usually metal) hands have a correctly sized hole for the shaft on which it is press fit. Additionally, you'll see a slot to provide for expansion of the hole with minimal distortion.

The video linked in the comments uses a different method, a form of doming the shaft opening, which is then sanded down to create a much thinner contact area on the shaft. The video also presents the device necessary to accomplish this task, which would add expense.

Consider to attach a metal shim at the hub of each of the hands with a similar (slotted) configuration. By having the shim to the back side, any visual contrast will be invisible and not detract from the overall appearance. My searches for slotted clock hands resulted in nothing useful. Perhaps it isn't a great solution, but I've seen (and assembled clock kits) with hands of this sort.

The metal shim effectively becomes the hand but the PLA material "extends" the reach for the desired visual effect.


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