Nut Block Break In

[Zat German]

The wiki build instructions state:

The nut blocks often start out with a bit of a tight fit. Once the electronics are installed you should run the nut blocks up and down the threaded rods, free of the gantry) using the steppers motors a couple dozen times to break them in.

I don't understand how you can run the nut blocks up the threaded rod without the gantry. What does "free of the gantry" mean? Is "gantry" a mistake and it is meant to say "carriage"?

[IPvFletch]

I also read this and got confused. Then like 3 hours later it all made sense to me.. I think..

You need to run the lead screw back and forth through that nut to break it in.. The best idea I've seen is to put the lead screw in your power drill chuck, and then put the lead screw into the nut on the Z carriages, and go FWD/REV back and forth a bunch of times until its broken in. This lets you work the lead screw and nut w/out the gantry being involved (or even moving). You can even do this before the gantry is mounted in place on the Z rails..

[Zat German]

That doesn't make sense to me if he is recommending you run it with your electronics installed which kind of implies the machine is assembled. Also, if you get your drill out of alignment, it could damage the threads on the nut block.

[rogue555]

I think the idea is to unscrew the nut block from its mating makerslide plate and hold it in your hand (to prevent it from spinning) while running the motor CW and CCW.

[Zat German]

I think the idea is to unscrew the nut block from its mating makerslide plate and hold it in your hand (to prevent it from spinning) while running the motor CW and CCW.

Seems like another bad idea to me for the same reasons as running it with a drill. You don't want either end of the threaded rod going out of perpendicular while it is breaking in or you get uneven wear.

[bdring]

I unscrewd the block from the gantry (carriage). Everything else was still assembled.

I manually ran the nut block initially down to the mid point by hand. I then just held the block in my hand and ran the stepper motors. After about a half dozen runs with a little lube they ran fine. You don't want anything with too much power in case there is something binding. The Quantums need a little more break in due to the small size of the motors. The Hadrons are much more powerful.

[mxk]

At download/file.php?id=2809&mode=view you can see some handles I made for this purpose. Like some others here, I was worried about wearing the nut blocks out of alignment if I took them off the gantry so I printed the handles shown and ran the gantry up and down a half dozen times or so by hand, taking care to return both sides equally. You could do the same with two M8 nuts tightened against each other (don't over tighten, you don't want to stretch the lead screw) and ratcheting socket wrenches. I wish the lead screws were about 30mm longer so I could have left the handles on.

[butterfingers]

This seems to be a noted issue on Reprap machines too. The recommendation there is a little light duty grease. Then again, they often use zinc plated rods.

[LeonS]

I had no trouble at all using the drill to break in the nuts. There may be something to the observation that you want to keep it perpendicular to the rod. But my experience was that there was nothing I could do to cause it not to be perpendicular. I threaded the nut onto the rod by hand and then held onto the nut and ran it up and down the whole length of the rod many times (like 40 times) by running the drill in forward and reverse. I even put some resistance against the movement so that it had to pull and push against the nut a bit.

I would be interested in a lubricant that is safe for the plastic nut. I used graphite lubricant but I don't think I would recommend that.

[naPS]

How much flex are you guys getting on the Z motor plates? During normal operation I can barely perceive it, if it's even there. And by normal operation I mean taking .2 - .4 mm steps. During high speed operation there's a very slight, barely noticeable, wobble on both the Z motor plates. It's moving a fraction of a mm, but it is moving slightly, and it seems to flex right back into place.

I'm not really concerned all that much about it, because the operation on the gantry end is very smooth. Even when the motor plates are flexing slightly, there's no noticeable wobble on the gantry at all. I'm more curious to see if others are experiencing this as well.