I came across this website literally as i was getting ready to place my order for CNCOX components.
I’m fascinated by the design, and will be going with this one instead, and not because I can do it for 1/3 the price.
First question: what’s the 30a power supply actually for?
I intend to use this primarily as a cnc router for 2.5d cutting. Eventually, I could see putting a laser on it, but that will be down the road.
Second, I see that this maxes out at 30 x 30 due to rigidity constraints. Has anyone tried filling the conduit with concrete and rebar to stiffen the beams? Or, would this over tax the steppers?
The 30A power supply is for your arduino/ramps combo, which drives the steppers.
Concrete will crack in the tube, and render what ever benefit it had worthless.
You can go as large as you want, you just need to brace the conduit. Others have done it with great success.
To be a little more clear. The 30A is needed when running a heated bed for 3D printing, and works great for a diode based laser power supply. The machine runs on less than 3A if all the steppers are moving at the same time, even less on normal use.
Making tubes more rigid isn’t really a good idea, if you are worried you can get slightly thicker walled Stainless steel tubes. But gannicuss is right depending on what tool you use and what material you plan on cutting you can go a lot bigger, and the mid span braces really help here. I don’t think a full sheet is possible but you can get one axis really long if the other is shorter, a large square is not recommended. But bigger is less rigid, so build as small as absolutely possible.
Note that the type of spindle you use has a big impact on the effective cutting area you get for a given foot print. For my standard 30" X 30" build with a DeWalt 660 router as a spindle I get about an 18" square cutting area.
Yeah, the loss of workspace is probably the biggest issue with the design. It didn’t sound that bad to me on paper, but once I started building I realized quickly just how much you loose. I’m more than willing to live with it given all the other positives that outweigh that one major negative (the biggest positive being I actually have a working CNC machine on my dining room table!) but it is worth considering when building.
MY final plan is to build it 36" x 48" so I can cut sheets of 20" x 30" foamboard. But because of how big a 48" square worktable is and how tight I am for space I decided to build it as a 24" square machine first which gives me about a 13" square workspace. You can see in the attached photo where I put a pen on my tool mount and traced out the limits of the work area (I actually did it twice due to some minor tweaks to the setup.)
It will soon be moving out to what used to be my office but is transforming this weekend into a workshop. I’ll also be re-building it as a 36" x 48" frame when I do that. Sadly we have no garage at this house On the upside, the lack of garage makes my wife far more understanding about my projects happening in the dining room, kitchen, outside kitchen, living room, driveway and anywhere else I can find space when needed It’s great to have a partner who understands my need to create and work on things!
My daughter is actually disappointed that it’s moving outside. She seems to really like the MPCNC. It might be because I used her favorite color (turquoise) for some of the parts, or maybe because the first things I made with it were a penguin drawing and an Elsa drawing for her…or maybe she just finds watching it work as fascinating as I do
I got the plug idea from another user on here who shared his method on thingiverse: http://www.thingiverse.com/thing:858155 Makes for very clean wiring! Unless you mean the caps which I also found on thingiverse: http://www.thingiverse.com/thing:783678 Tip - if you use slic3r then select “concentric” for the top/bottom fill it makes them look much nicer with a bullseye pattern instead of lines.
I used paracord instead of mesh sleeving to cleanup the stepper wires. That mesh stuff and I never seem to get along. Paracord isn’t much easier to work with, but the ends to unravel as bad for me. It’s a tight fit getting the 4 stepper wires through 550 paracord but can be done. What I did was tape the wires together staggered so each one started about 1/2" back form the end of the next one creating a cone shape that was easier to push through. I still have to cleanup my Z wiring and make some cable chains to finish cleaning it all up.
Jason
If you daughter loved the Elsa drawing, here’s an .svg of Anna and Elsa in profile. I cut these out of 3/32 plywood and my daughter loved it! Had a great time coloring in details with markers.
Enjoy
My wife and I battle over creative space. She has two bedrooms / craftrooms. I have the garage. My daughter is a maker at heart too. She spends much of her time with me in the garage. I’m guessing she is going to flip over this.
I machined the motor mounts out of 3/8ths aluminum plate, which was way over kill… but I had it laying around.
Also,
How tight should the 5/16 coupler nut be within the middle assembly… it moves around freely (up and down, it does not rotate)
I think I might have been off a little when I did the corners on the motor mount… do I need to stick another fender washer between the bearing and the mount to keep the belt on the bearing?
The 5/16" coupler nut, the long one, should be tight in the middle assembly. That’s the only thing that keeps the tool head from falling down. There are two z nut locks. One for couplers that are 11mm across the flats and another for 13mm across the flats. Pick the one that best matches your coupler. While the coupler nut must be tight in the lock the regular 5/16" nut, if you chose to use it, should float in the lock but not spin.
I decided against the aluminum brackets I made… I set them aside and may revisit them at a later date.
The only issue I see comming down the pike is my z axis. When I run it all the way up, I don’t quite have 2 inches of clearance… and that’s before tooling.
I cut my legs at 4.5" I’m going to cut them longer, but the question is… how much longer?
How did you machine the motor mounts? If those weren’t hard I would imagine facing them down to a better thickness wouldn’t be too bad either. Though it will result in a lot of “wasted” material.
On the upside, the lack of garage makes my wife far more understanding about my projects happening in the dining room, kitchen, outside kitchen, living room, driveway and anywhere else I can find space when needed 
It’s great to have a partner who understands my need to create and work on things!
