I would like to use 1" OD DOM steel tube for my MPCNC, which I would get case hardened for maximum durability. From what I’ve read, DOM had very good tolerances, and when case hardened should be even more durable than stainless. My heat treater says that the can straighten all my tubes after treatment for only a few dollars extra, but at 0.49 wall thickness they say its likely thy will only be able to get a 36" piece of steel straight within 0.035". They said if I can beef it up to 0.1" that they should be able to ensure a much better straightness.
My question is, how thick/heavy can the rails be before you start to run into problems with fast movements or belt stretching?
Weights of different DOM tubes, (two pieces, 36" each)
1.09" is 6.22 lbs
0.083" is 4.87 lbs
0.65" is 3.93 lbs