Hi all,
Just wanted to start buy saying thank you to all involved in the production of the long mill.
Canāt wait to use it. 
Now my question is:
How much resistance should be on the z-gantry bearings?
During initial assembly, the resistance on the z-gantry plate felt a little high when I tried to push it along the y-gantry plate.
If I tilt the y-gantry plate into a vertical position, the z plate does not slide at all without āgentle persuationā from my hand.
To me, this feels too stiff and will lead to premature bearing failure.
I tried to realign the x-gantry plate rails for a smoother run but the hole tolerances for the little bolts holding the rails in place are so close, that there does not seem to be enough room for adjustment.
When all of the bolts are loosened off the z-gantry slides beautifully.
What are other peopleās experiences/opinions on this?
On a side note, a couple of the small bolts that hold my x-gantry bearing rails in place, arrived over torqued during initial assembly and the threads were stripped off of these bolts. Please be careful if you do loosen the bolts for any reason, that you do not overtighten them.
@BenW we assemble the gantry assemblies in our office because theyāre very finicky and only ship them if they pass our smoothness inspection. If your gantry is binding as much as you say, itās possible that it mightāve been knocked around too much during shipping.
If you feel that you can fix the assembly yourself, I can try to walk you through the process we follow to get it running smoothly, but if not then Iād be happy to ship you a new one.
Hey Chris,
I am more than happy to sort this out myself but your technique in aligning the rails would be great.
Cheers
Ben
I apologize, I didnāt get back to you on this Ben. Do you still need the directions?
Yes please Chris. I have assembled the gantry but it still feels a little bit stiff on its rails. You assembly technique may very well remedy this issue.
I put together this instructional picture for you. I hope it help to make your gantry assembly run more smoothly:
@chrismakesstuff : I am checking to see if the above instructions are still valid for a LongMill 2.5. I figure they should be, as the basic geometry is the same, even if the components are a little different. But I wanted to check in case you have come up with a new and better procedure in the intervening years.
I am just starting the assembly process, and as with Benās experience, the Z-gantry binds. It is only loose within a few cm of what is shown as the right side in the first few Z-gantry images on this page. Everywhere else binds enough that gravity will not move the plate.
Thanks in advance,
Rod.
@rthinman since this weāve made much more specific jigs for in-house assembly so we donāt follow these steps, but for at-home adjustment then the diagram above Iād still consider to be quite good 
Remember that if youāre seeing issue with a component like this then weād be glad to replace it as well if you reached our customer support phones or email.
@chrismakesstuff I did in the interim reach out to customer support. So far, the advice was to complete assembly and send a video, which I donāt understand since the component is already binding enough that it defies gravity. I hope that the videos I uploaded over the weekend after various attempts to shim the z-axis rails to reduce bending make this clear.
In that case, whoever youāre speaking with just ask them to ship a new assembly since itās something we can certainly accommodate if youāve already worked hard trying to shim it
Will do. Thank you very much for the support.