Attaching spindle carriage to Z-axis

Hey all, first time assembling here and happy to join the community. I was doing fine until I got to this page - http://x-carve-instructions.inventables.com/1000mm/step2c/9attachmount/

As I tighten down the screws attaching the spindle carriage to the delrin nut, I can no longer turn the lead screw by hand. This makes me afraid to put a belt on it later and I’m afraid something went wrong because I can’t turn it anymore. Loosening the screws a turn or two allows the lead screw to turn by hand again.

Later on the page, it says to adjust the variable wheels so they fit snugly on the markerslide, but how can you move the spindle by hand to know since it’s already attached to the lead screw by that point and that’s the only way to move it?

I was doing so well… : )

Thanks for the help in advance!

Put the lead screw in a drill and run it back and forth (by hand) on the delrin nut multiple times to kind of “work it in”.
It is a snug fit for sure, and it should be.
Also lube the lead screw and nut with either Teflon or silicon spray.
I know your machine came with some lube, but I don’t know what it is and I didn’t use it for fear it would be a dust magnet.
Hope this helps you.

Thanks. I put then the nut on top of the lead screw into a drill and ran it up and down a bunch of times, but there wasn’t too much change. Added the lube and ran it again a bunch of times and that seemed to have loosened it up pretty well. It looks a lot like petroleum jelly. Thanks again!

Putting mine together now. I found that if you tighten the screws connecting the spindle carriage to the delrin nut TOO tight it puts the lead screw in a bind. I backed mine out and have noticed if I just snug it and not wrench on it that it rides smooth. I have locktight on everything that doesn’t have a nylon backed nut on it. Hope this helps someone in the future.

I shimmed mine with brass shim stock so I could tighten the screws firmly and not worry about them loosening.