Quick question

Mostly Printed CNC - MPCNC Advice
1

After a small trauma to the machine, I’m trying to get back up a running, but I do deal with a bit of chatter on 1/2" ply (although generally I’ve been happy with the results up to 1/4" ply.) I could make the machine smaller, but I’m generally happy with the work area, and want to try and keep it (about 17" x 24" work area currently.)

I have recently identified a source for metal tubing close to my house. My current machine is 3/4 EMT. I can get 15/16" Steel DOM. Mathematically this is close to the 23.5 spec of the model C. What is my tolerance in this before I have to print an entire new set of parts? Is 23.8 too far out of spec? ( Just rough conversion of the 15/16 DOM spec.)

Also - is this worth doing? I suspect the larger 1" tube would be better, but it does mean a whole new set of parts. (I spent up a bit on the printing since I live in Arizona. I’m printed out of High Temp PETG (prints at 300C)). So does DOM steel with a thicker wall still result in a significantly more rigid machine even if I don’t increase the tube diameter?

Figured I’d ask before I spend. You guys may tell me to forget it. Thanks all.

2

All I can say is 25 mm and 25.4 are distinct designs, and it would be nice if there were a universal set at 25.2 that was close enough for both. I’m not the first one to think of this and if it were close enough, there would only be one 25/25.4 size. So I would infer that 0.3 is too much of a difference.

Thicker wall does make a difference. Unfortunately the conduit is probably the one that could benefit the most, yet thick-wall conduit does not have the same OD. Someone once glued 1/2" conduit inside of 3/4" conduit, so that is an option.

3

Most of the improvement on the 1" DOM comes from the size, not the material or thickness.

That said, there is nothing wrong with an EMT build. There have been hundreds of MPCNCs built this aay and they work well.