I have the machine Low Rider finished as far as and. Everything checked. I also carried out the squaring. Successful. During the last inspections I noticed that the x-axis does not produce a straight line, but something like an arc. As can be seen in the picture, I carried out the measurements from left to right and zeroed all axes. I measured with a caliper. The measurements were taken using a 4 mm cutter against the groove of a 4020 profile. I aligned the profile with the two endpoints of the milled path, and that’s when I noticed the error. I measured a deviation of about 3 mm in the middle of the gantry; toward the ends the deviation decreases again.
How can i fixed that?
I would be very grateful for your help.
A low-tech way is to roll them on the floor to see if they roll straight or have any lift along the length. That’s how I tested them before buying them.
I check by rolling on flat surface before assembly as Vincent noted.
You could try to loosen the clamps and rotate the X tubes 90 degrees. If the tube does have a bend, then that should move the change to the Z axis. When I assemble, I always try to have any bend pointing up to try to offset sag due to weight of the router.
Your permanent strut plate may also help pull things straighter when you get those cut and installed.
Thank you for the suggestions to fix my error.
I haven’t milled the permanent structural plate yet.
Now I only don’t know which thing I should start testing to fix the error?!
It probably makes sense to insert the permanent structure first and then see if the problem is solved.
Just a note to mention that you should include a finishing pass when cutting your struts.
If the problem is indeed that the gantry tubes are flexing under load, the initial roughing pass will most likely be a bit bowed. The finishing pass will have a lot less load, so should clean things up somewhat (less load, so less flexing).
