Absolute Newbie perplexed and looking for sound advice

Mostly Printed CNC - MPCNC Advice
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Hello All,
I must say that this is one of the most helpful and true community-oriented forums I’ve been on is quite some time. I want to have a CNC machine for a variety of reasons but a lot has to do with not being on my feet so much and letting the CNC do things I no longer can do myself like wood carving and inlay work.

Here’s my “Dream” machine - a full sheet 4’ X 8’ with a z reach of at least 6" and I would like to work with material up to 4" in thickness, with a dropdown table and a rotary “A” axis that can turn 4" material as a minimum but prefer 6".

I like the portability of the Primo MPCNC but wanting full sheet capability its best to go with LR3 it seems, but what height of a Z rig can I really go to considering a possible drop table with an insert for the rotary axis with I have seen on a number of builds. I like the thought of adding a Laser or even Plasma cutter if a table insert was made for small soft steel parts (Not too often I would think but having that capability would be nice.

Ultimately this is what I want to do - building furniture and cabinet parts, lots of carving involved (with some by hand carving clean-up) inlays on panels as well as 3D dimensional signage using HDU or other High Density foam and hand carving as well. I don’t envision working with much metal, but that may change since I’m learning how to stick weld right now and this gives me some ideas with a welded table base but it may just be too heavy for me to move around, so looking at a home-built table like the bench below.

With the Primo I could initially use my current bench that I completed last year when I was still feeling “froggy” but after some back surgery later not feeling quite so froggy yet…grin. Here’s the bench I currently have, 4’ x 8’ 1.5 inch top. it’s a beast but easy to move around with heavy-duty casters.

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Like everyone these days money is tight, especially being a retired disabled Vet on VA/SSA fixed income. But, that’s why these builds are so cool for they “give you just what you need and then some” and the most reasonable in terms of costs involved. I don’t know which way to go at this point. I know I will need the Z depth, and although a full sheet is a great thought, but if I can use software that allows for paging or reindexing as a full sheet is moved through it (Primo build) I might be able to go with a 4’ x 4’ but with my desire for the rotary axis going almost the length of the top (with built-up spindle bases and sliding bedstock) again drives me back to the LR3. The workbench already takes up a lot of room but still would have some room at the back of my shop for a full sheet CNC as I’m cleaning out 30+ years of personal flotsum and many of my Dad’s stuff collected from 50 years as a Carpenter/Contractor.

You folks here have already gone through this “Gnashing of teeth”…lol, but looking for advice as to which way would be best in most opinions from those who are doing it and if I can only make one choice based on what I would ultimately like to do. Thank you so much in advance for any suggestions.

Here is the dimensions/Parts list I just ran for a 4’ X 3’ Primo build and will probably go with the Makita
If anyone has any suggestions on this I’m all ears. Can I go this big with the MPCNC? I also want to drive this mainly by wireless or USB directly connected to laptop and really liking DeskProto 7.1, but have other capable software for sculpting/carving digitally.

GrumpySarge_MPCNC Dimensions List 4 foot X 3 foot.zip (101.5 KB)

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The size seems doable, the 6’’ on Z are also achievable with a drop table. Normally you can mill around 3.8cm stock since the LR rises ~7.6cm (if you do not, like me, have an inlay endmill that is just incredibly long). Table looks solid! Just give it a go. :slight_smile: You’ll learn along the way.

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Hi Philipp,
So you’re recommending the LR3 for this size and not the Primo MPCNC? If I do the 4X3 size I could probably mount a secondary table on one half of the bench with a removable insert for the Rotary axis or remove the whole insert for deeper cutting but I think I’ll still have to add onto the Z axis bars. But I don’t think I could do the rotary axis with the MPCNC, but I assume I can with the LR3 just because of the difference in how the machines work/move.

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I’m in the same boat…ish I’m struggling to decide. I just got a really silly idea to cable mount a torsion box to my ceiling with a hoist mechanism. So I can run a full size sheet of MDF on the mill, but get the entire unit out of my way when not in use.

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Must have a tall ceiling…lol, otherwise I’d feel like I was walking in a Hobbit’s den…grin. I’m starting to look at things differently though, I can start out with the MPCNC which although smaller footprint it can give me more versatility initially, e.g, Laser or weld a slatted steel tray for a plasma cutter. I can always create a dedicated LR3 machine down the road as I gain more experience/confidence. Still would like to figure out if I could still rig something up with the MPCNC for the Rotary “A” axis for table/chair legs. I’ll have to learn how I can do half a carving and then reindex it to finish the other half - don’t know how that works yet.

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I built the primo and love it first.
But found out that really I wanted a lr3 for what I had pictured. Iirc I think the primo can have flex issues when you get into the larger things.
It’s also convenient being able to just buy a full sheet and put in on the table and go. My table design is still in the works but was meant to be semi portable and able to mount on lots of things like tables or have a drop in the middle.
That table looks very nice btw!

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I can safely hoist the jeep top up and store it in the hoisted space without causing any issues for anyone under 6’6"

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I built this gantry crane 8 feet above the floor for refence.

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Pretty darned ingenious solution really. I wish I had the high ceilings. But, I’m still thinking about putting some lumber racks up there to use some space more efficiently. There’s an area of my shop that just screams wall mount racks as well, so maybe I’ll meet somewhere in the middle…Lol.

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lumber racks you say? these were SO easy, are strong like bull and VERY inexpensive. Drill holes in 2x4 at 15 degree angle and insert 3/4" emt

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That size would be way too big for a primo. Mine is 2’x3’ working area and it is too big. You run into issues with significant flex mid span. I’d seriously say you should go wit a lowrider. If I did it again, I would have build a lowrider.

I’ll be shrinking my primo down to 24"x 24" in the near future.

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For Z capacity, a drop table will add stock height, but do keep in mind that you will still only get about 75mm of Z travel. (I get about 50mm extra for mine, so a touch under 5".)

I do not know about the practicality of swapping between a router and a plasma cutter. Those seem to need a different operating environment. I dream of building a plasma cutter, and doing it on the LR would be pretty awesome though. (My solution will likely be a second LowRider.)

My Primo is 2’ × 3’, and is too big. I get vibration issues near the middle of the axes. While it is usable if I am careful, I do not really get full use of the machine, which is why I built the LowRider. I plan to “cut down” the Primo to smaller dimemensions… As soon as I am sure I won’t need it before I’m done…

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Same, started with a Primo, ended up with a LowRider. :smile:

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this might be my answer eventually. Smaller primo for sub 12" stuff with a LR work horse for everything else.

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I was absolutely new when I built my MPCNC and it showed in the choices I made. The cut area was only about 18” x 24” and I got too much chatter for the plywood I wanted to cut. Ended up cutting extremely slowly, which I didn’t think was a big deal until I wanted to get more done. It worked great for a laser but didn’t have clearance for a rotary.

MPCNC also is like other traditional CNC units where rigidity decreases as you extend the Z axis down into the material. The taller you make it, the further the Z axis must extend from the X/Y gantry rails.

One of the genius features of the lowrider is that it is more stable at the height of the rail and rigidity decreases as you move to higher Z positions.

If you usually cut sheet goods but occasionally want more Z I’d suggest a lowrider with a drop table. If you usually cut softer materials but much thicker (with only occasional harder sheet goods), the an MPCNC with more Z may be any option. But you’ll want to elevate the sheet goods so you don’t extend Z so much when needing rigidity.

Of course even if you want a quarter sheet build a LR3 is probably a better option for most materials. It sounds like size alone may determine your choice.

I only have a couple years experience at this point, so YMMV.

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I’ve built two LowRiders, one for router (that does full sheets of MDF or plywood), and another one for plasma (that does about 50" x 30"). I second what Dan said. The plasma is greatly benefited by having its own type of controller setup, and its own kind of floating Z torch holder, not only to get access to a standardized approach to probing to the metal and automatic torch height control, but also for the awesome cut job recovery options provided. Please check out my extensive video playlist on my plasma build: https://www.youtube.com/watch?v=MV-IcyFUPQs&list=PLiW6LQZxE6JZW8mClbsKFIjO5VFjzxklS

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perfect!!! I have the same large free area above one wall with a bench/cabinets across the bottom. I was debating putting cabinets above them, but some lumber racks would make more sense. were these homemade or purchased? if the latter, where?

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After reading some other comments on size limitations with the MPCNC, going with the LR3 from the beginning with a torsion box drop table with a rotary A-axis insert seems to make the most sense, especially one that I can install on top of my existing “Monster” Bench which would allow me to extend it so I get a full sheet, and if designed properly, can be removed and stored aside if necessary. I definitely have some design work to do…grin.

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I’m only looking to do 16/4 stock with enough rise to clear the stock with a long cutter bit. The drop table idea with the LR3 is looking more and more like the solution if I have to choose only one to start. I can look to make a Primo 24"x24" down the road lor plasma but have to research the best base for plasma and yes, it will probably need a different control set up as others have noted - not worried about that now, just the design for the LR3.

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made them. I followed this video almost to the letter.

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That is awesome, I don’t have quite that much space, more along the lines of what you did, but not like I don’t have 10" EMT conduit lying around…LOL. bought for the MPCNC, so if I’m going with the LR3 I won’t need so much.

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