Yes, you will need to cut down that screw. I made mine a little shorter than the Z tubes. Technically it can be as short as just a few threads into the nut on the top of the core, when your Z tubes are level with the bottom of the core. Because your Z tubes should never come up past the bottom bearings.
To cut it you could use a cut-off wheel, or hack-saw. Make sure you put the cut end into the Z motor coupler so you don’t bum up the core nut.
+1 What Tim said. It’s actually in the build guide, but I did the same thing, realized I needed to read it more closely when I saw the problem with mine. Easy fix with an angle grinder, cut it a little shorter than the length of my z tubes, then used a sanding disc to kinda make it convex a little (probably not necessary).
So I took a break and I’m back at it again today. In need of one last piece of advise before i start sweating.
Do i need to disassemble the lead screw from the stepper motor to cut it or can I cut it while it is the assembly? Will the vibrations from hacksaw affect the assembly? Really feeling lazy to disassemble and do it.
I didn’t remove mine. Made it easier to know where to cut. Idk that I would be able to fit a hacksaw between the rails, though. I’d also be pretty bummed if I ended up bending the z rod. Probably best to remove it. I’ve figured out that building the mpcnc benefits from more plan/prep really. Shouldn’t be much hassle to remove it, though.
Haha, I say it because I’m basically an ogre and will just bang parts around until they fit unless I make a very conscious effort to do things right. Lol