Precision/accuracy of MPCNC Primo vs LowRider?

LowRider CNC Advice
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Hello folks. I’m contemplating a first build, and I’ve got a beginner question that may have been answered a thousand times, but I can’t seem to find the right search terms to bring up such answers.

Is there a difference in accuracy and precision between the latest design of the MPC Primo versus the LowRider? Naturally, like everyone else, I’d like the largest build area possible, but I’m wondering if the LowRider can’t do the same level of detail as the MPCNC. I’m planning to do both large, rough designs like boxes and baskets with the router, and small, intricate designs like the kind you see in Rolife/Robotime kits with the laser.

Is it wishful thinking to believe that one machine can do both? Are they really designed for different types of jobs?

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Welcome!

I built the MPCNC Primo and working on my Low Rider 4 and in the final stages. My understanding the Low Rider gives nothing up in accuracy and precision but I of course am not the expert here.

I personally did not go full sheet and chose a 2’ x 4’ (quarter sheet) area for my needs. I loved the Primo but really like the open structure of the Low Rider.

You find this a great group of very helpful people.

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I’ve never built an MPCNC, only LowRiders.

That said, Ryan has demonstrated milling PCB blanks on a full sheet size LowRider.
It gives up nothing in capability.

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According to the documentation, if you are going to build a bigger machine, you want to use a Lowrider.

From the MPCNC docs:

All axes can be any length you prefer, anything over ~3′ (1M) would be best to start with a LowRider CNC, of course smaller is better.

Also, I believe from everything I’ve read, they are both going to be accurate. I have an LR4. It is pretty accurate. I am not machining parts that need crazy tolerances. I am getting ready to build an MPCNC for a laser.

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I’ve had both, I’ve done tiny inlays on the LR3.

The LR4 is even more accurate. I’d always go LowRider.

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I built a Primo first, then LR3 now LR4 (762 x 1524mm) I guess it depends a little on which axis you think would be most sensitive to variation. There are 2 motors on the LR Z axis, so getting it acceptably parallel to the work surface might take a couple of extra minutes. There’s only 1 motor on X which might impact raster speeds with a laser depending on weight (whether you feel like you need to remove the spindle completely when switching to Laser.) I found squaring the LR to be easier than the Primo but YMMV.

I absolutely agree that LR4 is my default recommendation. Hopefully Ryan will have time to chime in.

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That’s when you buy a closed loop stepper. :face_savoring_food:

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yes, indeed I do! That’s why I felt bold enough to ask a possibly dumb and repetitive question.

whoa, okay, that’s evidence enough.

Amazing that you were able to do the negatives and have them mesh together so cleanly.

Thank you all for your recommendations – the consensus seems to be that the LR4 is perfectly adequate for fine detail.

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This forum gets surprisingly more views than posts. For every question you are brave enough to ask, there are many folks wondering the same thing but just weary about asking.

Thanks for asking. The only dumb question is the one you didn’t ask.

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Actually the one question I asked on the Primo build I would laugh at today. Ryan was suppling a DC power supply for the SKR Pro and it was a standard computer power source. I spent about a 1/2 hour looking all over where to plug it in. Finally posted the question. Ryan politely answered just cut off the jack and fasten the plus and minus to the power input! Ooops.

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Also not a dumb question. Ryan’s solution is a clever one and not terribly obvious.

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