Is it possible to use 25mm tubes with 25.4mm parts?

I have the 0.065" wall 25.4mm stainless tubes from SpeedyMetals, and while they’re nice and rigid, they’re also incredibly heavy. I have a large build, and would like to cut down on the weight by using carbon fiber tubes for the Z axis, but they appear to only come in 25mm. Given that it’s only 0.4mm difference, how likely is it to fit my 25.4mm parts?

If they were going to work anywhere it would be there. The issues will be tighting it that much might throw the whole center out of square, and carbon fiber tubes will delaminate under the high point load of the bearings, I am just not sure how fast.

That makes sense about pulling it out of square… What about 1" aluminum tubing? since it’s just the Z axis it seems like the stress shouldn’t be a problem, unless it dents or something?

I’m looking at this:

For my purposes that would be 2x 12" @ 0.128 lbs = 0.256 lbs!


Nevermind, just read the FAQ about aluminum tubing… I think I might give the carbon fiber a try – it’s fairly cheap.

Why are you trying to change it?

The weight difference of the Z tubes is pretty minimal, you still have the much longer gantry tubes. Mine works fine in stainless. If you have issues try fusion and the new post processor, or just turn down all the accelerations a tiny bit.

The steppers can rip the machine off the base if you are not carefull a few extra ounces should be nothing.

To be honest I don’t really know if I need to… But if I do, I want to get my order in before China shuts down for a month due to their New Year stuff. I’m already switching out the DW660 for a spindle and saving about 1.5lbs in the process (the DW660 cuts fine, but is too loud since I mostly have to do my CNC stuff at night). I figured I might try and save another 12 ounces or so while I’m at it. I have a 7’ axis, so even a little weight can go a long ways. That said, I’m not really getting much vertical flex, so maybe I shouldn’t worry.