New User Leveling X-Axis

CrossFire ® Assembly
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Just wanted to share my experience.

I bought the table assembled from a user who only assembled the table and never used it. There were a few loose nuts and bolts, and the gantry arm leaned down REALLY hard towards the far end of the X-axis. I could also see only one side of the top bearings (inner) was riding on the steel Y-axis beam. So I started messing around with it trying to get it straight and tight.

What I ended up doing was loosening all of the bolts for the bearing supports (red aluminum blocks that hold the bearings), as well as the 8 bolts that hold the bearing plates to the gantry carriage (4 on each end). Then I lifted the far end of the gantry tube (X-axis) and propped it up. It was in a position where there was some force upward on the gantry tube. I then tightened the 8 bolts, 4 on each side of the gantry carriage. After that, I clamped opposing bearing blocks together. I used a woodworkers sliding clamp, first on the sides, and then on the top and bottom. I was hoping to put a little bit of preload onto the entire assembly, so the weight doesn’t cause sagging across the X-axis.

This helped, but it wasn’t good enough for my taste.
I eventually ended up shimming the gantry tube, on top of carriage arm/bracket. I think I used .07" washer on the larger bolt, and around .15" on the little hex socket head screw near the thinner part of the support arm.

This helped out quite a bit, and the X-axis varies across the entire table, but I attribute some of it to the slats, uneven slat supports, etc. I guess I’m chasing precision that just isn’t available on this type of linear motion support, and it’s probably not necessary?

I haven’t fired the torch using CNC control yet, so hopefully it’s close enough.

The Y-axis, well, I haven’t really tackled that yet.

I’ll try to keep posting as I go on to get it set up.

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1114200042%5B1%5D2581×1936 1.87 MB

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Work only with the eight bolts securing the gantry to the Red bearing block. They should be just snug enough so it can hold the gantry with the torch at maximum X, yet allow you to move the gantry up and down with a little force. Measure and adjust at minimum and maximum X points until you get it. Mine was a royal pain in the ass to get done, but after a few beers and some cussing I got it sorted. There’s a Langmuir vid on this somewhere and also another independent on YouTube, I’ll try to find and post them. Now that I have THC on-board, it’s no longer an issue.
BTW I just had a closer look at your measurement setup, don’t use a slat laying on its side across the table as a measurement reference, it most likely is bowed one way or the other. Instead measure to the top of the innermost and outermost slats along the X axis.
Good luck and hope this helps!

UPDATES:

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Cletus,

Thanks for that info. It is nice to know the forums are active and other people are resolving the same issues I’ve experienced.
I think the real test will be if I can get some test cuts done soon.
I think I’ll start with some rectangles instead of straight lines. This way I can test different feedrates and test the plotter travel for squareness at the same time.

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Yup, my first cuts were 2" squares with a 1" center hole, to check linearity and symmetry then progressed on to corner gussets with holes and more complex cuts. Took it one step at a time to get the feel of things and get the equipment dialed-in. Have fun!

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