Sorry if it’s already been addressed on here, I just got into MPCNC and may be a little behind the curve. I started printing parts for a Burly, read a few posts of people saying they would abandon it and go Primo instead, so I did.
My question is regarding some tubing I ended up with from a sort of flea market kind of a place, it measures exactly 27mm OD, which is 1.06ish inches. Would it be possible to make that fit with the 25.4mm version, even if I had to scale every piece up 1% or so? Would that affect other things negatively? I thought about printing a test piece to see if it might fit as is, but just wondering if anyone knows what kind of tubing this is or has any experience they want to share. The tubing is crimped to a point on one end like its made to be driven into the ground I guess, and theres a ton of it still there for super cheap, and its really sturdy so I wouldn’t mind using it if I could make it work.
I think it would take a bunch of work including re-modeling some of the parts to make this feasible. Here is a post of someone who scaled the MPCNC to use 1" conduit which is about 29.5 mm. His topic highlights some of the problems you may have. For example the hole spacing for the NEMA 17 motors will be enlarged and therefore will no longer fit the motors. I would be concerned that the holes for the bolts the bearings ride on would be enlarged and become sloppy. The holes that are used to hold down the T nut and to screw on the limit switches would be too big for the specified screws and possibly too spread to mount the part. The spindle mounts would need to be enlarged to fit on the tubing/mount and therefore might not fit the router/spindle without modification. And I’m sure there are more items that will need to be addressed. And the topic I mention above cuts off before he is finished with the machine, so we don’t know if he got it working well in the end.
If you decide to move forward with this project, go down through the part list and think through every place where a piece of purchased hardware (bolts, belts, steppers, etc.) is married to a 3D printed part and what that would mean when the plastic part is enlarged.
@NapAndGrit where are you located? If in the US, it probably is best to just go to Home Depot and get the EMT conduit as it’s cheap and in stock. And you’ll know it works without messing with things.
I thought of going with the 1" tubing but figured for a first build keeping things as basic as possible would be wise as there is so much to learn. Now maybe it’s me and getting older, but I just don’t have the patience to chase problems that won’t be easy to fix.
If you’re outside of the USA I can’t help but others can. Come to think of it, not sure I’ve offered anything useful. But hope you have a good successful build.
FYI, all of the concerns you’ve listed, i’ve addressed. If I remember correctly, the core was the only part that was directly scaled using the slicer software. The bearings and bolts used are 6000-2rs and 3/8” bolts, not the 608’s and 5/16”. The holes scale up perfectly for 3/8” bolts. A printed bushing takes care of the lead screw nut mounting.
The trucks, corners, belt adjusters, all were edited in fusion 360, so no issues there. Waiting for warmer weather to finish assembly.
Yeah sorry I forgot to come back and check for replies. Yes I’m in Alabama and I did just come to the same conclusion, happened to find some EMT at the same store (they only had one piece so it was hard to find) and then I had a few more sections left over from jobs that I was able to get what I needed out of. I’ll probably use those larger ones with the conduit clamps to build my table.
I looked at your post, nice work! Yours is still conduit, though, what I have I’m pretty sure is not because it doesn’t have the inch marks etched into it and it has those weird crimped off ends that make it look like a giant needle, I’m not sure what it is. I actually just tried a similar approach to a much smaller project and instead of scaling everything up I tried to edit all the holes in blender to match the linear rods and nuts that I had available but I probably wouldn’t try that again unless I absolutely had to, way too much work. I got the standard EMT and printed out all my parts except the core, waiting on a new roll of filament for that.