MPCNC with no legs.. Instead on a MDF box?

Hi there, I am constantly fixing the little tightening lugs on all my corners as they seem very prone to cracking. I cannot tighten them too much as they crack, but also can’t blame them for cracking as they are just little things holding the clamps in place.

What I was thinking is making a complete box section for the tubing to sit on with custom corners to hold the tubes all in place in the box or on top of the open top box section. Has anyone done similar and dumped the legs all together? If so I would love to see any pictures of how they have done this. If not then is there any negatives in exploring this path?


Huh. That’s interesting. I am assuming your just talking about parts in the corners, not entire sides? Can you extend the pipes and just support those with some wooden towers? If you leave the corners installed, then you don’t have to mess with the belts.

I am thinking of redesign of the complete corner to corner with a box section with poly carbonate inserts to MDF. That way remove all the corners and design new corners to attach to the inner corners of a box. Obviously a not so tall box, maybe 150mm tall sides, with printed outer joiners.

I was hoping I could get my hands on a MPCNC as Fusion360 file. Has anyone designed the complete machine in Fusion for remixing?

You might look into building a flat MDF top with a square center cut-out, and then building the box underneath to lower the cutting area. Then you can use the dimensional analysis here to get your measurements for your own polycarbonate corner blocks, I found these dimensions to to be extremely accurate and worked for me.


The corners don’t really do anything and should need hardly any tension on those screws. My rails can rotate on the corners, you just need them so the belt tension can not pull them together.

The corners linked above are similar to the very first versions I made. We used electrical conduit boxes for feet and legs, sounds funny but actually worked very well. I switched for two reasons, the embedded nuts had everyone underwear in a knot and if the prints weren’t really good the bottom piece being shaped like a C would flex open and actually offset the top enough to cause tension in odd places. So if you use them they are great just make sure your printer is in good shape.

Or you can print the corner pieces out of another material, petg? Just take it easy on the tension as it shouldn’t be needed.

As for the new design your thinking of, I would love to hear more. As for dimensions there really are only two you need to worry about the rail to rail distance is a tiny bit different for all three machines, and the belt location is basically along the inside edge of the top of the rail (as in it rides on the bottom of the bearing that rides on the top of the tube).

I am starting to feel the very strong urge for a redesign but at this point it will take some serious time.

I built a U channel plywood box using the standard corners:

It works OK but doesn’t provide a significant improvement and access is slightly worse.

This image doesn’t really help too much. But art the very basics all I need is end collars, and incorporate the right height for the belt ends. I then have a way to attach inside an MDF box. I then no longer need the legs or end joiners at all.


The lityle orange collar is just me mocking up an idea while I design how I will do it.

My critical dimensions are the spacing of the tube away from the sides being 30mm to allow clearance of tge carriages. The height of the belt tensioner from the centre line of the tube. I think those two are all I actually need to ensure are correct

Other than that the next is to ensure the pipes are all parallel and at equal heights. Hence the collars can simply screw into place rather than boring holes the MDF for the pipes to sit into.


Thoughts on these parameters addressed above?

This is what I have in mind for a full boxed enclosure. What you don’t see is that the front panel will have a cutout for a poly-carbonate insert to go in the mdf frame like a window. That was my kids can see without getting any hands in the area at all. It will contain any little cuttings this way as well. I still have to design up the end collets that will fasten to the MDF sides, and incorporate the belt fastener ends.

Please feel free to add your thoughts on how I can design these end collets and keep them fairly simple.

I think the little orange collar will work. Make sure you seal the MDF real good though. It will move on you throughout the seasons. Hardest part will be squaring it all up and keeping the spacing.

I have a good 2 pack sealer which I will spray with 2 coats between sanding. I 5gem have 2 pack auto paint in gun metal grey in satin. I will use my corner bracing that I use in furniture making tho get this square on each corner sand fasten with 50mm Deming screws to pull the corners together, and hide those under the printed corner braces.

At the bottom I will make 18mm corner fillets in the internal corners. I will then make a few cross braces out of 18mm which the spoil board can screw down to.

I think with those things being done I should have a very sturdy base for my pipework to sit into. My one concern is the box section may amplify the cutting noise like a speaker.

My other concern is getting the belt tensioner ends in the right place. I will probably model the end clamps with built in belt tensioner similar tho how they are on the sides of the clamps.

Do we have these corners somewhere in fusion360? If so it will save me time remodeling something that was already done. If not I will just model up new ones.

I wanted to see what the corner braces look like on top of the dark grey. I got lazy and faced the MDF a quick brush with no sealant so I could see the colours together.

Corner collets now designed and printed. These work fantastic and are to the right dimensions for offsetting the belt tensioner. Am pretty happy so far. I will create the box over the weekend and brace it up to see how it goes together. I am not worried about not being able to get access to it inside once boxed as I will drop hinge the front panel.

And attached is the printed end collet. I have just screwed it to a scrap piece of MDF

What are you planning for cable management?

Thin black sticky back electrical conduit boxing.

Box painted and looking ready for second fitting.

WOW that looks pretty dang good so far.

Yea, I’m digging it!

I a.m. getting that little bit closer. I took it all apart this morn8ng after ferrying everything lined up perfectly to give the box another coat of polyurethane. One thing I noticed is that if any of your rails on tge sides are off by a fraction it turns the center into a seesaw type action. I didn’t realise but one of tge little spacers between the pipes had a bit of dirt stuck in it so it had one side offset by about 1mm. Enough to throw off alignment. Tge way o have designed three little pipe ends allows you to rotate the pipes enough to give some adjustment up and down. With the little bit of dirt removed it has fixed my small issue.

So far I have the center in and will rewire soon. I just ordered some black sticky side conduit that I will hide my wiring into, as well as a couple of cable trays to get the XY into. I have not used cable tray before so it will be interesting to try work out.

Are you going to cut openings or anything in the sides? How are you going to get material in the box?

I will cut a drop down side tomorrow. I will also route a recess into the drop down for some plexiglass to sit in it. Still a bit to do.