New and improved z motor shaft coupler

Replace your existing z motor to all thread coupler and never ever worry about this part coming loose again! I have tried several different solutions including thing 117950 by 1013 (http://www.thingiverse.com/thing:117950/#files).

Until now his motor to M6 connector was the best option.

Interesting. it’s certanly never going to accidentally come loose thats for sure. Is there enough flex in it so as to not induce slight part layer shifting? Or are the TAZ springs able to fully absorb that?

The new beefier springs by 1013 on thingiverse is the way to go and, yes, it can absorb the unwanted movements.

http://www.thingiverse.com/thing:117950

I just went with the stock vinyl tube for my in-progress Taz. Did you find that there was slipping with that method?

Not necessarily slipping, but there is rotational flex, which will mean Z-axis errors when it raises and lowers (hysteresis errors). you can see this yourself by rotating the threaded rods by hand while the motors are on and holding position. they will rotate 5 or 10 degrees in both directions.

In an Ideal motor coupler you want some flex in position and axial angle, but ZERO rotational flex…it is hard to get that in a coupler, especially a printed one.

This coupler does look a little stiff to me. but as long as everything is aligned and your threaded rods are very straight, it should work fine.

Ok. I will conduct a simple experiment to measure this backlash as soon as I get this thing finished (~1.5-2 months away).

A very tight hose clamp or two on each coupler would minimize this hysteresis, no?

When I used the tubing I didn’t notice a huge concern. The torsion slip 1013 is talking about can be minimized with a reduced length of tubing. However, he is correct on this matter. On the other hand, a very strait threaded rod is good to have in theory, but I have a little “wobble” in the x-y plane and this is fully absorbed by 1013’s z-springs.

A clamp won’t get rid of the problem 1013 is talking about. The issue is due to a material property. I heard that there are a lot of production printers that use the tubing method with no issues.

The threaded rods have a pitch of 1mm (1mm Z travel per revolution). so if you have a worst case scenario of 10 degrees of torsional flex (both directions) then you have a Z travel of 0.056mm ((1mm/360 degrees)*20 degrees).

this is not much to worry about for most prints at 0.25mm layer thickness (22%). but if you try some 0.10mm layer prints, then it will likely become more of a problem…