Eccentric Workshop Forum

So i'm currently in the process of building a Mostly Printed CNC (see v1engineering.com). By the book you're supposed to use a MiniRambo or a RAMPS board (which i had laying around) but it just felt really wrong and odd to use a 3d printing board and 3d printing toolchain for milling, I was just imagining having an LCD staring at me displaying the temperature of a nozzle that didn't exist and sending all my gcode through Repeteir host.. so i'm glad to come on board with GRBL. At least i'll still be able to send my gcode through UGS. I'm currently printing plate 4 of 5 of the 3d printed parts, so I'll do my best to try to keep a buildlog here.
Mill size will be 400x400x74mm
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Sounds great! The MPCNC is what got me started on all of this. I didn't like the Protoneer offering so I built my own and made it better. The demand has been so good it's keeping me just busy enough I haven't yet finished my own MPCNC build. I've got all of the parts just waiting.

I look forward to the build log.

Happy Fun Solder Time!

Also update... All pieces except one of the XY blocks are printed. The XY went slightly too close to the edge of the build plate and the print was essentially truncated to where the part was unusable. The new version of Cura thinks the Ender3 can do 235mmx235mm... maybe i need to update some settings in the TH3D community firmware? IDK. Reprinting that last part now.

I've cut all the conduit and reamed the ends. I think I probably should have put the conduit in a vice while using the drill reamer attachment because when it would bind up either the whole drill would buck and whack me or it would wrench my wrist really hard. I didn't think i would need to do that because the reamer manufacturer just showed construction guys doing it freehand.

All the parts have shown up, except the very important 5/16x1.25 bolts which somehow escaped being ordered. This is probably a good thing because i needed to write some curriculum for my engineering students over the weekend (we're building fighting robots) and the lack of those bolts forced me to manage my time better.

At any rate, the feet are put together, and the z-axis part is assembled.

Soldering done! It was a pretty enjoyable Sunday afternoon project. I was pretty excited to test it out so I hooked the board up to 12v and 3 motors and set them on top of a box.
Whiiiiir! Whiiiiir! Whiiirrrrrrr!

Sorry for the shaky video... I had a bad habit when i was a child of holding solder in my mouth :-/

Project is currently stalled awaiting delivery of aluminum extrusions for my baseplate frame. Expect updates in a week or two. Kinda bummed because I could really use the distraction of $ownProject while dealing with everyone's STEM EXPO projects that they waited until the last minute to work on. Ah well!
oh.. also test-fit all the parts together...

Still waiting for the 2020 extrusions to arrive. I decided to spend a little time planning exactly how i'm going to mount this thing down. As usual, I do the majority of my planning/thinking in Inkscape.

I used the length of the pipes i cut and layed them out in a square overlapping them so that the outer corners touched.


Then I took the foot model and sliced an SVG from the bottom.


I aligned the feet so that the center of the conduit hole was overlapping the corners of the pipe. This gives me the footprint of my machine.


I modeled a 2020 extrusion in inkscape using the profile drawing provided in the ebay listing.


I aligned the extrusions so that the feet could bolt directly into them with T nuts. This gave me the lengths that I need to cut the extrusions.


Then I started working on the wasteboard. I made a duplicate of my work and uncombined the feet objects. I drew a 700x700mm square with 8mm radius corners and combined the holes from the feet with the square. I added some more holes at regular intervals around the edge just to increase rigidity and also one in the middle to bolt the wasteboard down to a crossbrace. I realized that I would only have 6mm of mdf between the bolt and ripping out the side, so I increased the dimensions of the wood by 40mm on a side. It was about this time that i realized what an incredible pain it will be to have to completely disassemble and reassemble the machine just to change out the wasteboard. I decided i needed a 3 section wasteboard that would allow me to just replace the central working area. Since i did not wish to loose rigidity of my work surface I increased the number of cross braces from 1 to 3. This means the spoilboard is held down by 9 bolts which will probably cause me to cuss a lot when I have to get those nuts to line up. There's probably a better way to do this and this is probably over-engineered but that's my style.
Final Table:




Bill of Materials for Table for a 400x400mm Mostly Printed CNC:

Type	Length (mm)	Width (mm)	QTY
Al Ext, 2020	660	NA	5
Al Ext, 2020	700	NA	2
1/2" MDF	740	740	1
2020 Corner Brace	NA	NA	16
T Nut	NA	NA	47
M5x8 Screw	NA	NA	32
M5x15 Screw, Button Head	NA	NA	19
M5x22 Screw, Button Head	NA	NA	12

I wrote a procedure for myself to put the table together. The materials list changed a bit, and probably will continue to change once i start putting it together.

Edit: Fixed some errors in the materials list. Also realized I only really needed 1 countersunk hole and it would be easier to do that with the drill.

Looks good. I usually fly by the seat of my pants when building things, but it helps to at least have a rough plan. I started my journey into cnc work with a mpcnc, it's a good gateway machine. Now I have a 6k lb 7.5hp machininng center in my garage that I use for prototyping miscellaneous projects

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Thanks. Really I'm just impatient and writing the instructions out felt kinda like building it.
Being an apartment dweller a laser, some 3d printers, a cnc router, and a drill press is probably about as far as I can push things. Maybe throw a mini lathe in too. As it is I'm already pretty restricted in where I can move based on if someone is going to throw a hissy fit about venting the laser out the window. I don't think my floor could support that much machine either and as much as I'd love a basement machine shop, i don't want a suddenly basement machine shop