X-Axis rail tolerances?

I’ve been working through assembling my new machine and I’ve run into a bit of a snag while attempting to install the XZ gantry on the X-axis. After about an hour of adjusting the eccentric nuts, I still wasn’t able to get the fit correct. One end of the rail was always so tight that it is difficult to move the gantry at all, or the other end of the rail would be so loose that there is enough slop where I can rock the gantry back & forth on it.

I started taking some measurements, and it appears that one section of my X-axis rail has a “bulge”. When I took out the calipers, the distance between the rails where the v-wheels should sit varies by as much as ~0.7mm along the length of the rail. Most of the rail seems to be around 170.0mm from edge-to-edge, but in one section near the end it has a minimum distance of 170.6 - 170.7mm.

Is this variance within acceptable tolerances? If so, is there anything I can do to get this gantry to ride smoothly along the entire length of the rail? Or what’s the best compromise if I have to choose between play at one end or the other end being extremely tight?

I was thinking I could possibly clamp the area that is too tight and attempt to bend it in just a bit so that everything is smooth, but the wife told me I need to wait to hear from the community before I attempt something like that, lol!

Thanks for any advice!

It sounds like your rail is out of spec. If you’d like to try a bending operation that may work, and if you’d like a compromise I’d try to adjust the wheels so that they satisfy the mid-point distance so that they’re a little loose at the edges and a little tight at the center. Alternatively, you can get in touch to us (https://sienci.com/contact-us/technical-help/) and we can arrange a new rail to be sent out.

I have the same problem with the reinforcement X-axis rail, with the exception being the amount of warpage. Mine measures a whopping 1.244mm (.047") in the centre. Yikes!!

I have just filled out a contact form and sent it on its way, requesting a replacement.

Marty from Kingston

Wow, talk about outstanding service! In less than 48 hours after reporting the problem that I was having with the X-axis reinforcement rail being warped, I received the replacement rail. I can’t say enough words of praise about how the Sienci Lab’s staff looked after me. (Thank you, Kelly!).

Marty Schlosser
Kingston, ON, Canada

1 Like