Someone wanted to do some learning experiences with circular motion so my mind first went to making tops. Obviously we could make them from recycled materials & junk, or even some actual hardware (like bolts or eye screws). But Eric Steele had just shared “Grandchild Gift” on Cuttle to laser cut a Spinning Top.
I thought we could explore various distributions of the pennies.
I made one of his to play with, then designed something like it, but the shafts were just a simple slot. My first mistake was “rounding” the rectangles for the shafts… the slots don’t end up the same height :
meaning the supports nubs for the round platform are not at the same height. Also, for some reason, I made the shafts 3/4″ while his are 1/2″
My second change to his design was to eliminate the penny slots (at least for now). The bottom is just rounded and the platform is a full circle. I think that platform is what students can play with : add weights in various locations, cut out sections, make different size or shapes as the platform.
Interestingly enough, even when you put the support nubs at the exact same height on 2 different pieces of the shaft…they don’t end up at exactly the same place. I am thinking that has to do with kerf and the way the slot gets cut out. So i had to trial and error to get them the same. (notice the tiny gap in the picture on the left)
Now I have a 3/4″ shaft file and a 1/2″ shaft file .
The platform is up to you/the students. It just needs the appropriate size cross in the middle (two rectangles placed perpendicular – both 0.125″ by 1/2″ or 3/4″)
(video https://youtu.be/MRIye2PVJ1M )