On Sat, 04 Jul 2020 21:18:47 -0400, Joe Gwinn
wrote:

On Fri, 03 Jul 2020 22:27:23 -0700, pyotr filipivich
wrote:

on Fri, 3 Jul 2020 09:53:42 -0700 (PDT) typed
in rec.woodworking the following:
Hi!

I am a teacher and I want to make a few of these gadgets for a project this fall. I'd like to make zoetrope/phenakistoscope boxes. My students will make the actual drawings, but I want to make some interactive display cases so they can show their work off to the rest of the school.

I'm not sure how to explain what I need - sort of like a lazy susan on a kitchen table, but that will spin for longer when spun by hand. I'd like kids to be able to run their hand around the outside rim of the wooden circular platform to get it spinning the right speed, then be able to just watch for maybe ten seconds without having to continue spinning it with their hand.

Lazy susans mostly have a track and spheres which will bear the
weight and roll. (That's why 8th grade shop classes make lazy susans
using marbles for bearing. "Cheap" but works)

What you want are "regular" bearings: bicycle wheels would serve,
support the axle. Details as an exercise for the student.
After that its just about anything with an axle and a set of
bearings. Replacement bearings can be had at hardware stores, part
shops, skate board, or biycle shops.

The right way to do such a thing with real bearings is to use a short
vertical shaft with two bearings, the upper one having tapered
rollers, the botton having needle rollers. The load is on a circular
plate attached perpendicular to the vertical shaft. The vertical load
is carried by the upper bearing, and the bottom bearing resists the
tipover forces. The reason for needle rollers is to not trap the
shaft axially between bearings - there needs to be some give,
especially over temperature.

If the frame will be made of wood, one will need to desgn for
tolerance of angular misalignment, but there is enough give that axial
trapping will not be a problem.

One source of suitable bearings:
https://www.mcmaster.com/bearings/ball-bearings/ball-bearings-8/

Self-aligning flanged bearings:
https://www.mcmaster.com/bearings/ball-bearings/self-aligning-flanged-ball-bearings/

GAWD. Talk about overkill.

This is a zoetrope https://youtu.be/u2v-L-1Kctk

This is a phenakistoscope https://youtu.be/2rzwdRqsuVM