Sizing Advice Requested

Mostly Printed CNC - MPCNC Advice
1

Hi - I have all my printed parts done and I’m ready to start cutting my tubing. I just would like a little advice first.

I originally had in mind using this to cut a wing rib out of 1/4 plywood for an ultra light project. The rib would be quite large, 48” long and 10” tall.

I printed all my parts out of PET-CF and it’s very strong, very stiff stuff.

I purchased 1/8” wall 4130 tubing and so my rails are very stiff as well.

I’m thinking about trying for a 49” x 25” x 8” workspace, but I see all the comments that doing that would be way too big.

Is there any chance that the stiffer materials I have planned to use with let me make this larger than recommended? Has anyone tried to do this before? I have no problem adding mid span supports if that’s what it takes.

I figure if it’s the much to big and there is no accuracy, I can always cut down the tubing with minimal waste. If I start small, I’d have to re buy everything to make it larger.

2

Are you thinking about that workspace for the 3d printer or for a CNC? MPCNC or Lowrider v3/v4?

3

For the MPCNC. Al parts made from PETCF and 1/8” wall 4130 tubing.

4

I can’t remember if it’s v3 or v4. I started printing it in 2023 if that helps date it. I can check when I’m back at my computer.

5

You need to be more clear. There is no v3 or v4 MPCNC.

6

That size is too big for an MPCNC. A LowRider V4, on the other hand, would be really stout in that size.

One reason that you’re confusing folks is you posted this in the MP3DP section of the forums, and a MP3DP is Ryan’s design for a flying Z 3D Printer.

As others have asked, exactly what are you thinking of building?

7

Is there any chance that they use the same hardware pieces or the same kit I purchased for the MPCNC? Apologies for posting in the wrong spot.

8

The electronics are the same. 5 stepper motors, control electronics, switches.

The nuts and bolts have some crossover. 608 skate bearings, 5/16" x 1.5" bolts, nuts… some of the M5 hardware.

The problem with the LR4 is that the rails are different. The Primo uses 23.5 (3/4" conduit) 25mm, or 25.4" (1" tube). The LR4 uses 1" conduit, 30 or 32mm tube.

You could use the same tube for a LR3, which would still be excellent at your target size. 25"x49" would make a very nice LR3 still very capable.