Is this a good idea?

After reading around I've become convinced trapezoidal lead screws are the answer to improving the Z axis of my boxed frame Prusa i3.

On finding this integrated screw NEMA 17 motor it seemed like the ideal solution -- Direct transfer from the motor, no complications with couplings.

However now I'm torn.

Could I be setting myself up for problems with this rigid solution?

Would screws I could adjust/ remove/ replace be a better option?

Is there still something positive to be said for flexible aluminium couplings?


If anyone could offer me their advice on this it would be much appreciated.




Direct Leadscrew Stepper Motor

It seems to me that this would remove the problem of having the lead screw and the stepper axle not aligning axially through the coupler. I've had some sub-par couplers that actually pushed the lead screw off center because their bore was just a bit too big.

If the screw and motor specifications are what you need, I'd say this is worth a try

Seems a good idea. Im buying fine thread lead screw at the moment. The only thing you have to be careful with is not creating any misalignments in your z axis rods and the lead screw. If thats of your inviting shear force and further problems. But I havent seen someone test a rigid connection vs flexible couplers. Let me know how it turns out.

Experience with engineering fundamentals help for this question.

The idea is fine. Make sure you don't fasten one end of it down or is will cause wobbling. Long rotating rods have a higher radius of gyration if you fasten them on both ends. Your threaded rod being smaller is lowering the radius of gyration, and allowing a little required deflection. So is the rule behind structural column bucking. half the probability of wobbling if you only fasten the motor side.

In the picture, do you have a seat for the z carriage thats round there?

Vinyl tubing can be used as a coupler with some zip ties. Some 3D printers made professionally use that method.

I bought a pair of these motors with integrated leadscrews from robotdigg.com and I wouldn't hesitate to use them again. I special ordered a pair with 450mm Tr8*8 leadscrews and have been incredibly happy with them on my clone of the Lulzbot Taz. They're so straight and smooth that I'm thinking about getting another set to upgrade the threaded rods on my Mendel.

I turn shaft size (+ a couple thousandth) bores into the ends of my rods, and use tiny set screws to attach. I've had my bed moving for hours with no issues.