Mobile version / mount frame

For a new build we’re considering to create a bit more mobile version, by not mounting it on a full table. Having just the upper part would make it much easier to transport in the back of a car, for example. I know the entire machine can be unmounted from a table quite easily, but then you’ll have to screw it to something else and ensure it’s squared, etc…

So we’ve got the idea to build a square frame which holds the feet of the MPCNC. A bit similar to https://www.v1engineering.com/wp-content/uploads/2018/07/20180717_091933.jpg (found on https://www.v1engineering.com/forum/topic/a-texas-rebuild/ ), but then larger and perhaps have a steel frame welded instead, for added rigidity.

Besides being able to easily move the machine, we were thinking an added benefit might be the possibility to clamp the frame to a large surface (like a large table or a door) and engrave directly on it, through the “hole” in the frame. This way, you’d be able to work with objects that normally wouldn’t fit between the MPCNC feet.

What are your ideas on this? Any advice is much appreciated, thanks!

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I’ve thought about this as well. Would be pretty neat to be able to route inlays directly on wood floors. You could probably do it with aluminum angle, or aluminum U channel. Weld it into a square, then cut off most of the walls so they only stick up maybe half-inch to an inch. Mount the feet in the corners and Bob’s your uncle! Use some of the replacement rubber strips they make for track saw tracks for grip, and some lead shot bags to keep it from moving.

That would be pretty cool. I don’t see why it wouldn’t work. I hope you try it out.

What’s the minimum envelope that your are looking for height wise? Incrementally smaller pieces of conduit(or any other rigid like material) and some set screws might do the trick…

@barry

You could probably do it with aluminum angle

In yhe steel stud world we use what we call “shiney 90” do you think starting at 16 gauge and going all the way to 25 gauge would accomplish this? Granted 25 gauge 90 bends when you look at it…

The “mobileness” of my frame (the Texas rebuild…) was initially envisioned as the base of a portable machine that could be clamped to large slabs of wood and allow engraving the surface. A friend of mine is in the tree services and has a yard full of gigantic, conference table-sized, slabs of wood… so large that the machine must be taken to the work rather than vice versa. He makes a lot of outdoor benches and furniture and we talked of the possibility of adding engravings to his work. We never followed through on the idea but that was the plan…

Like Ryan, I’d love to see this idea developed further… =8^)

It seems not all pics came through, let’s try again.

OK, now my previous post disappeared. Not sure what’s going on, but it seems to struggle with the image uploads, even though they’re just ~300kB each. Anyway, here’s my original message, put the pics on imgur:

Thanks for the replies!

Did some renders. Barry, is this what you mean? https://imgur.com/a/5Y01GGL and https://imgur.com/a/xVKhqxs I’ve used 70x20x2mm aluminium angle (sorry, metric here) which I can get locally here. The additional holes could be used for either mounting it to a table or screwing a spoil board onto (or under) it.

In the last picture (https://imgur.com/a/A57M2rC) I’ve used 80x80x8mm aluminium T-profile: the outer edge has some more holes and can also be used to clamp it down. The top should probably be trimmed quite a bit, because this 80mm tall “wall” might not be ideal, but for now I just kept it at the original aluminium size (could not find 80x20x8 T-profile).

Do you think a frame like this (either L or T shaped) would be sturdy enough for a build of around 600x600mm work area (meaning a frame of around 900x900mm)? How about the material thickness? Is 2mm to thin? Is the 8mm overkill?

https://www.homedepot.com/p/ClarkDietrich-1-1-2-in-x-10-ft-20-Gauge-Galvanized-Steel-Corner-Bead-727234/204713529

Being the non-elegant construction type, I would suggest something like above. 20 gauge can still be flimsy though, I would suggest 16 or 18 gauge.

Also home depot is wrong when they call it “corner bead”. Corner bead is an entirely different material and paper thin or evev literally paper sometimes.

Yep, that’s pretty much what I was thinking of. The angle should keep it from twisting, or at least lessen it.

I tend to over engineer…

I’d use square steel tubing and weld a square frame, then mount the feet to the frame with tapped holes.

Reduce the height of the legs by the height of the square tubing.

I’d use square steel tubing and weld a square frame, then mount the feet to the frame with tapped holes.

Do you think some neodymium magnets jammed into the legs would be strong enough to hold the mpcnc place?

Another idea: aluminium extrusions!

[attachment file=64948]

Standard size, no cutting or drilling or welding required, tons of mounting options on all sides.

Used in the render above is 4040.

I like the aluminum extrusion. The t or v slot leaves alot of options for modular addons. I have a cheap manual leveling line laser the I use to level my workpieces. Right now it is attached via magnet to one of the legs. Mounting to the slot would look way cleaner.

Side note: what software are you doing your renders in?

Fusion 360

Skip the legs and feet all together.

Good idea. Up until now I was trying to keep all of the original printed parts.

I guess I could design a custom part that fits/locks nicely on the rails. Should this be a custom Bottom_Corner part, and then skip the Foot + leg conduit + Lock_Corner parts? Could you confirm this? I think it does need some Z clearance so the roller won’t be touching the extrusion.

There is a hole in the bottom of the corner bottom part just screw it in. You can razor off the little alignment tab. The frame should clear the roller bolts but if it is too close just flip them over heads down and you will have more room.

This lets you set your Z bit clearance with your frame thickness (in place of the leg lengths), 3/4" would probably do. Just build the machine before the frame and test your offset. Hard to explain. The bottom of the tool mount is just about the same level as the bottom of the roller bolts so you need a bit of room to be able to retract the length of your endmill, about 3/4"-1".

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What about something like the drawing (sorry, I’m not an artist)? I’ve priced tslot 2020 and it’s not much more than EMT at the end of the day. Hell, unistrut might even be viable, but spring channel nuts and other hardware aren’t exactly cheap.

Not completely sure what the upper part is in your drawing, but did you mean something like this:

[attachment file=64997]

This is the Bottom_Corner part, with a guide attached that makes it slide onto the rail. It still needs to be bolted down with a slide nut though.

Don’t you think 2020 might be a bit too small? That’s why I’ve chosen 4040 here. Another option would be a 2040, which is a double 2020, so twice the rails. I’m not sure what’s best…