i have completed my build and everything is working except my z axis. It won’t budge or it gets stuck. the z tension screws are completely loose (all of them are). And my z rails are parallel. In the pic i am pointing at which piece of the “heart” is causing the tension, but im not sure how to stop it from being so tight. any suggestions??
If i help it a little by hand it goes up and down fine. It seems like i need a more powerful stepper motor for the z axis. its even worse when i put the spindle on. it misses steps and gets stuck at times…
If you turn the screw by hand, does it move smoothly ? are you sure it doesn’t bind against anything inside of the Z assembly “tube” ?
I had a problem when the motor/screw wasn’t absolutely vertical. Is it OK for you ?
yes everything rotates smoothly until it gets to that bottom bearing then its really tight. i don’t know how i can fix this issue. 
really bums me out
My guess is it is leadscrew alignment related.
At the very bottom is where all the alignment comes into play. Sometimes you can loosen the T8 nut screws and just move the brass nut over a smidge, sometimes the Z mount plates are not parallel and the kick the lead screw out at an angle.
Take the Z axis out of the gantry, is the leadscrew straight and parallel to the Z rails? Also have you lubed the leadscrew, metal on metal needs lube.
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yes everything seems parallel, and lubed. i can’t tell what’s making it bind.
There is an easy check. Take the leadscrew off. Does it still bind?
i may have found the issue, how would i adjust this Ryan? It looks like the lead screw isn’t in the center of the hole when i take out the brass nut. pic is attached.
You have to check everything. If your Z plates are not parallel they can kick the lead screw out. without being there it is hard to tell. Where does it sit when it is as close as you can get and still see in. Kinda normal to be a little crooked ant the end, but that is not the issue it is and the bottom position, much more important.
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it looks a little more centered when all the way down.
Well now you know the issue has to do with the leadscrew and nut. I can’t really tell you what is wrong you need to find it. I have given you a few things to try.
Put the nut back in without the screws, make it go all the way down. Does it bind? If it doesn’t it means you put the nut in off center originally. If it does it is probably in the Z mount somewhere.
There can be little print artifacts in the XYZ parts. You might want to try trimming the sharp corners and cleaning out the edges.
I think i may have found the problem. which stinks because i don’t have a 3d printer :(. both the top and the bottom broke like that. which is what’s allowing my leadscrew to move. dang.
That should not actually be the issue. Try a few drops of superglue in the cracks and you can add it around the seem as well. The glue sticks really well but not permanent so you can get it off later. That crack just means you really over tightened it.
That just holds to stepper to the rail.
when i move those two around though (because they are broken) it moved the position of the lead screw. you don’t think that is affecting it? hmm
If anything they would move and make it easier to use. Think of it this way, if the mount wasn’t there or made of soft rubber the stepper would just move to the path of least resistance, not make it worse. The fact that it does moves proves something is out of alignment.
If you bought the plastic from me and have anything else to order I will throw a new set in with your order for free. The problem is just some sort of miss alignment.
Have you tried any of the other things I suggested? The nut with no screws and check for Z plate parallel? I have built my fare share of these and I only suggest thing s in the order of likeliness.
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i just took apart the z rails, going to glue the pieces and then put it all back together ensuring they are parallel. I really appreciate all the help man. ill let you know what happens here in a few. thanks again…brb
quick question, when putting on the z motor plates. its nearly impossible to slide the bearing onto the t8 leadscrew…is that normal?
ok, so i put everything back together and same result. i did find however, if i leave the two black screws on the brass nut loose, there was no apparent issues with moving the z axis up and down…so i guess the brass nut needs to move a little (maybe a slightly bent leadscrew? idk). is it ok to leave those screws loose and let it ride like it is?
It will be fine like that, really it is only there to push against.
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Alright, well lets go do the crown :D. thanks for all the help Ryan, means alot