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5- Thrust bearing from mcmaster-carr (square turntable, found here http://www.mcmaster.com/#swivel-plates/=eltxix)
The problem I've been seeing is that even with nothing on it, after a quarter of a rotation or so the thrust bearing will start making noise and get stuck.
I am not sure but it looks as if the bearings may be getting "squished", probably from some misalignment. The motion overall is not nearly as smooth as when I make the same connection with no thrust bearing.
I tried getting a much more powerful stepper motor as well [...] but the problem is still there.
I believe it may be due to the way the shaft is connected to the bearing (i.e. using a set screw). Do you have any ideas as to what would be a good way to do this?
How is it if you turn it by hand?
Personally, I'd get a real thrust bearing where each ball (or needle) is caged.
a photo/sketch would help
What is supposed to go on top of it and what is the weight of this load?
I am able to turn it by hand when it's not connected to anything and the motion is pretty smooth.
Can you please point me to what you'd consider a real thrust bearing so that I give it a shot? I picked this one because it was easy to screw onto acrylic sheets.
I've attached a quick schematic I made in paint (excuse the newbieness). My gut feeling is that the motor is either not spinning perfectly orthogonal to the sheets, or that it is not exactly at the center of the swivel plate. Also, adding a load might be exaggerating this. I did get those acrylic sheets laser cut to what I think are accurate dimensions (since I was having the same problem when I drilled them myself). What would be a good way to fix this design?
The load should be able to go up to 50lbs. I've seen the stepper motor I have spin that amount over a quarter circle or so before getting stuck
(but then again it also gets stuck on no load). Also, this should be able to turn in small angle increments (i.e. it's a very low speed thing) - for example the stepper motor I have has a 1.8degree stepping angle and it would be ideal if the system as a consequence was able to turn in these increments.
you need a fairly substantial motor to turn lbs50 without losing steps, unless you gear down (to increase torque).
For a hose made coupler, is the attached what you had in mind? From a search on the internet for this it looks like "helical beam couplings" somewhat meet this criterion. Are there any "standard" flexible couplers that do this or were you thinking more of actually cutting a piece of tube and then gluing it to the surface and shaft?