my z axis motors cant lift the gantry. please help

My lowrider CNC z-axis cant lift it does move down but can’t go up. I am using a mini Rambo and moving it with reptier host.

Wired in series, what steppers, are the rails rubbing, did you lube the threads, is the brass nut loose, what firmware?

plugged it to the two z motor ports. motors are nema 17

the rails are fine the force is the same that is needed to move my 3d printer.

and I am using your pre config marlin firmware

the brass nut is firmly secure



That is parallel, you need series.

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Wait in series is better than parallel even when there are 2 ports? I am having the same problem (my lowrider started up after a year of building, 2 babies, and a career change). I thought the series was just for the x (or y depending in how you call if, the long axis) where there was only 1 port.


Side note, I changed drive strength from 80 to 100 or 90 to 110, cant remember, and it fixed most problems, but I assumed there was a reason to was set where it was, so I am still trying to figure it out, will try rewire when I get hone.

If the Driver is confitured for 1.5A (say) they are each only getting .75A if they are wired in parallel. If they are instead wired in series, however, each motor will receive the full 1.5A which is what you want.

Haha so a little bit of digging, 4 drivers x y z e, I though with 2 ports, there would be 2 drivers for z. I’ll have to dig and see if I’ve got some more plugs to make another series coupler. Only saw the one (used on y axis) but it’s been a year since I bought everything.


Contemplating just reporting the E driver for the other Z then I get all the torques.

So more than once in this build have I had to take foot and insert mouth. Found the second series cable, and all my problems are fixed. Will be buttoning it up and posting in the completed lowrider thread shortly, only a year and some change after I started printing.

Ryan, my hats off to you, both for continued support through the forum (and email), and for making a hell of a budget product. As I was assembling stuff the little engineer gremlin in side me had MANY ‘that’s why he did that moments’. You are an expert not only at designing a great product, but understanding when something is absolutely good enough to save the end user some money without sacrificing quality.

Well done and thank you everyone.

Side note, while fighting with the z axis I accidentally over drove it and the tubes came out of the lower bearing carriers, this showed me 3 of my 4 Z tubes were properly aligned, but one needed some adjustment, I’m sure its posted someone else as someone else has undoubtedly done the same, but for those that find this thread searching, it could help.

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Thanks, that was a great thing to read!