Mtcl's MPCNC build - Minneapolis, MN

Build has started:

11/20/2020

11/21/2020

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Your use of small blocks for the corners enables something interesting. I don’t know how much experience and/or reading you’ve done on CNCing, but after you gain a bit of experience with your machine, you will likely want to surface the spoil board. Surfacing is using a larger bit to skim the top of the board so that the top of the spoil board is parallel with the plane of the MPCNC machine. Most of the MPCNC machines that are pictured on the net cover the entire surface of their base board with spoil board material. That means that surfacing creates a pit in the spoil board, since the bit can only reach the cutting area. This pit makes it difficult to mount stock that hangs outside of the cutting area. But if you keep your spoil board to the size of your cutting area or smaller, you will not create this pit, and can have stock hanging off the edges of the spoil board. I made this change when I upgraded to a Primo, and it has helped me several times.

Hey @robertbu,

The corner blocks are made exactly to fit the spoil board. Those blocks are 3.5x3.5 and 1.5 inch tall (made from a regular 2x4 wood). I bought a spoil board that will sit in between, I’ll post the final design (the spoil board is in the same picture in the back against the wall). It’s a 3/4 inch thick board. It will be raised by 3/4 inches with support pieces throughout so that it’ll be flush with the corners/legs.

Being primarily a wood worker, putting those corner block also enabled me to fix a small hight adjustment while levelling legs. And if I ever need to reuse the table top for some other purpose, i can easily do that by unscrewing it.

What do you use for the spoil board?

I used 3/4" MDF for my spoil board. Most of the MPCNC machines pictured on the net use MDF. As for spoil board size, I’m suggesting that there are benefits to making the spoil board no bigger than the size of your cutting area and positioning it so the router bit just reaches each corner rather than making it as big as the span between your blocks. Spoil boards are replaceable, so it is not a big thing either way.

That’s what i got for my spoil board as well. Medium density 2x4 feet in size. I’ll cut it in smaller size to fit the area that I need. I see many people use the spoil board as a peg board and they use the MPCNC to make those holes as well. That looks pretty neat to me. I have to figure out how to do that, but that’s what I am aiming for.

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I plan on building my mpcnc on 3/4 inch mdf, then I’ll replace the 24×24 work area with 1 inch mdf that I will then surface down to almost 3/4 inch thick so that it is flat.

I think for sturdiness, you can use 3/4 inch plywood as base, and then 1 inch MDF as spoil board.

My reasoning is that any twists and sheerness on legs will be more supported in a hardwood than on mdf, so it’ll be better for longevity of the machine.

To be fair that will only be the rop layer… but I will consider using plywood, it would make it look nicer. I plan on mounting that 3/4inch to a pice of half inch osb that is the top of my table… I will post my model when I’m done with it :slight_smile:

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If you do a good job of leveling the machine with respect to your spoil board, you only have to skim off fractions of mm to get it level with respect to the machine. And, without a vacuum setup, surfacing that much spoil board with make a horrendous and potentially toxic mess.

Thats a good point, maybe I can find some 7/8" MDF instead.

I think what @robertbu is saying is that even 3/4 mdf is pretty good for spoil board as long as levelling is done right.

Ahh yes maybe, if I can get my bench that close… we will see, I am not always the best at that… thats why I am building a cnc, once I get it true everything I make will be true XD

Progress:



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Don’t judge my color choice haha. My reasoning was that the 0,0 coordinate should stand out. And the closest x axis should be easily located when I move it :slight_smile:

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Looking great! I think we were working in tandem today here in Minneapolis.

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I was going to finish it today, unfortunately the lead screw is too big. I posted a question in advise channel to see if someone has suggestions for me.

I cut mine down today using a dremel tool with a cutoff wheel. I cut it to the max length which is flush with the bottom of the Z axis and then beveled the edges to allow for easy threading. Worked like a charm.

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You can also put the cut end into the coupler at the top so the factory end is left out to screw into the lead screw nut.

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It looks like it is just a small progress since yesterday, but i had to make two trips to Home Depo. Lead screw cut and the Makita mount, mounted. This is how it looks nowim getting a little anxious with all the wires. Routing them through the conduits and getting the right length and all that is overwhelming.