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Three screws for bed leveling

Posted: Fri Oct 28, 2016 10:39 pm
by daveapplemotors
There are four screws to connect the print bed to the carriage and to level it but you need only 3. With four holes I warped my print bed and bent the single strength glass on top of it. That caused problems.

Have you ever seen a 3 legged stool wobble? Me neither!

The hole is already in the rear of the heat plate (between the heater wires) so only one more hole is needed. You must drill the carriage under the hole in the heater plate and you must tap it 3mm X .5 threads or use a nut. I drilled my aluminum print plate too.

With 3 screws the bed is much easier to level. And this morning I started print with a 0.1mm first layer! It is too bad I didn't do this earlier...

Re: Three screws for bed leveling

Posted: Sun Nov 27, 2016 3:47 pm
by Errol
This sounds like a great idea also i have started to put together 2 gt pulleys and put them on the top of the z axis screws and join the two screws together with a gt2 belt and bearings with housings to hold them in the correct alignment and only run 1 stepper motor to drive both screws and hopefully stop the creep between the 2 screws which is the biggest contributor to have to level so often

Re: Three screws for bed leveling

Posted: Sun Nov 27, 2016 7:37 pm
by daveapplemotors
"Creep between the two screws" -- If that means that your two z-axis motors lose sync then raise the voltage at the Pololus slightly.

The backlash--the slop in the mechanism-- at the top will be hard to deal with mechanically, I bet. Harder than getting them to stay in sync electrically.

Re: Three screws for bed leveling

Posted: Sun Nov 27, 2016 9:44 pm
by Errol
What do you mean pololus ? Do you mean mean trial error on the stepper adjust mean or can it be done using a multimeter is this to allow for the wire lengths to each one

Re: Three screws for bed leveling

Posted: Mon Nov 28, 2016 2:58 am
by UndCon
Yes - you calibrate the stepper drivers with multimeter.


In this post you see where to measure and what voltages to aim for.

http://www.geeetech.com/forum/viewtopic ... 17&t=17038

Best regards