Is the Low Rider best for me?

Hi, I’m looking to build either a low rider or MPCNC machine to assist with my building of large scale RC airplanes. Initially I was all in on the MPCNC, however as I thought more about it I do not need any kind of z axis movement because I will simply be cutting 2D parts from (usually) 3mm or so plywood for my models. And because my planes are larger in scale, I was teetering on the max build size recommended in the MPCNC literature.

Am I better off going with a low rider? At minimum I would want the cutting area to be 30"x30", but preferably I would like 36"x36" or even 36"x48". As I said, no z axis movement will be necessary since I will just be cutting 2D parts from sheet stock, so does the low rider sound like the more viable solution to what I’m needing?

Thank you in advance to any advice and comments to help me out!

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Even with sheet stock you may want Z motion, for example to lift the bit to cut out the interior of a former, to “spot drill” marks for drilling out later on, or to cut through harder or thicker materials in multiple passes. (Routers don’t drill very well - since the bit spins so fast the edge of the bit tends to cut better than the tip.) You’re going to have Z motion capability with either machine, so I’m guessing you’ll find good uses for it.

I would say if you’re confident you’ll get to 48" material, go for the lowrider.

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Awesome, thank you for the reply! Yeah, I had figured most of my parts I will cut out would fall below the 36" length, but that is until I thought about how if I went with the Low Rider I could technically cut spars and stringers or any longer pieces I may need for a wing or fuselage using it. So yeah I think the Low Rider makes the most sense for me, I may only use a 30"x30" area on it most of the time, but when I really need a 48" stringer something along those lines I think I’ll be happy I have it.

Do you recommend using the Makita router for this one as well? I saw in the literature for the MPCNC it stated it was the best choice when it came to precision and rigidity, so I assume it’s the same on the low rider as well? Or do you recommend something different for it, such as a spindle?

Thanks for the reply!

Some random thoughts:

The general lore, including statements by Ryan (designer of both machines), is that the MPCNC is a more accurate machine (compared to the LowRider) below 36" X 36", but I’ve never seen a real comparison, nor a statement of how much more accurate. And I don’t know how accurate you will need to be for your planes.

If you design your table and spoil board right, you can cut things longer than the working area on an MPCNC by indexing the stock…essentially sliding the stock down in a controlled manner and doing another cut.

I’m an MPCNC owner, so most of what I know about the LowRider comes from reading on the forum. According to posts on the forum, it is possible to remove the CNC portion of a LowRider and use the table. So if you are using a tight space, having the table do double duty might be a deciding factor.

I don’t believe the smaller Dewalt DW660 that is common on the MPCNC can be used on the LowRider. Almost all LowRiders I’ve seen on the forum use either A Dewalt DWP611 or a Makita RT0701C (or similar). Last year the DWP611 was difficult to get, and most people were going with the RT701C or the European equivalent. I don’t know if this lack of stock is still true. It is highly likely you will want to purchase a 1/8" collet if you get the DWP611 or the Makita RT0701C.

With either choice, given the the 3mm stock, you could consider cutting your parts using a laser. The NEJE A40640 is popping up a lot on the forum lately. It will cut 3mm plywood at around 200mm per min at full power…though for extended jobs I’d likely want to cut slower at a bit lower power to preserve the laser module. Kerf is small with the laser, so you will have the ability of doing more detailed cutting. With laser cutting, you would have to deal with the smoke and dark edges, but setting up jobs is faster, and you don’t have to deal with tare out of the wood at the edges of your cuts.

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And sharp inside corners are possible with a laser…
Fwiw, i hung a laser off my dust shoe and used it that way.
Also, when you eventually decide you want a primo anyway, you can use the lowrider to cut the spoilboard. I like to use a big cnc to make holes for the legs. WAY easier to square the machine, lol.

Thank you Robert and Tony for the great insight! A laser had never crossed my mind, partly because I always assumed it was more for balsa and soft wood like that, but if it can handle 3mm ply maybe it needs to be considered. Couple of questions after reading your posts:

  1. With a laser, is there more of a learning curve or additional things I need to be aware of? Or is it just essentially another means of cutting? This machine will go in my workshop basement, so not having sawdust from a laser is huge, but how much smoke does it put out? Enough to set off a fire alarm? Also, do you have to use a different kind of underlayment/spoil board for a laser?
  1. Tony, you mentioned “when I eventually decide I want a primo anyways…” are you saying I may regret the low rider as opposed to the primo? Honestly, the only reason I’m leaning LR is because of its ability to cut longer pieces, which would be huge for me when it comes to cutting stringers/spars for my planes. Before I discovered the LR my plan was going to be to just buy longer stock pieces and cut by hand, but I would much rather do it with a CNC for its accuracy and precision. If you’re saying I will eventually want a primo because maybe the LR isn’t as accurate than that is a game changer for me, because accuracy is what I need the most when cutting things like wing ribs and things like that where they all need to be uniform and true to the design.

Width of the machine can honestly be very minimal for my needs…in other words a machine that is 16" wide could serve me just fine, as I said above length is what I’d value if I had the choice. The only reason I started leaning LR is because it seems when the primo gets up to 36" or more it can lose some accuracy (according to other posts), but if making a primo that is instead 16"x60" or something like is possible I would definitely consider that.
I know I’ve said way too much for a post like this, so basically just to sum it up if I could have my dream machine for my basement workshop it would be a 16" x 60" (or longer) cutting area, preferably laser to cut down on dust assuming it doesn’t produce large amounts of smoke and also for precision and less kerf, and only every need for flat/2D cutouts from typically 3mm or less plywood stock.

Laser cutting some materials (like vinyl and PVC) produces toxic fumes (like chlorine gas or HCl acid vapors) so they should never be laser cut. Cutting wood will produce smoke which will be proportional to the amount of cutting being done, and the smoke can interfere with cut depth and quality in addition to being bad for your lungs. It is pretty common to use both “air assist” ( a jet of clean air on the cutting focal point to keep the beam clear) and an enclosure with exhaust fan to remove the combustion products. You’ll want to at least consider factoring those into your design of adding a laser.

Ah, ok interesting. Yeah I will typically just be cutting wood, but I didn’t want to have to deal with enclosures and exhaust and all that, I think I’ll just stick with a router or spindle for the cutter. Thanks for that info!

I haven’t used the last suggested, but my import “5w” laser made enough smoke that i opened the garage door. If your basement has a window, you’d want to open it.

As for the primo, I’m not saying you’ll be disappointed at all. I’ve just seen a lot of folks realize how great these things are and two are even better than one, especially when they cost so little to build.

The reason Ryan has two cnc machines is that they are good at different things, and the more you develop your skills, the more projects you’ll want to use them for. At some point, it’s reasonable to want the second machine that’s better at other things. Maybe you won’t fall into that category, maybe you will…time will tell.

Tony, you nearly read my mind. I’m really starting to wonder if instead of trying to build one machine to handle everything I want, I should look at possibly employing both machines. Maybe start with the Primo first (since I hear it is more user friendly) and get familiar with CNC in general , and then add a LR down the road if I start to realize I need some bigger cuts than the Primo can handle. Also, I just realized on some of my models that will use gas engines I may need to fabricate my own engine mounts and other parts out of aluminum, so I think it makes to have a smaller/more rigid primo in my shop for things like that.

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See? That’s what I’m talking about!

I will say that

  1. the Lowrider is capable of cutting sheet aluminum. Somebody posted video of his cutting a fan shroud for a Porsche or something like that.

  2. I just enjoy my primo more. Somehow feels less fiddly.

  3. the folks in here USING lowriders regularly can certainly offer advice to make the LR more enjoyable, i just never got that far because I did a poor job on mine and turned it into my primo.

  4. you could always build the primo, learn on some small parts, rebuild it into the lowrider for larger parts (after cutting the plates out on the primo) , and use the lowrider to cut an accurate spoilboard for a new primo.

I think option 4 seems pretty reasonable, given your concerns and likely projects.

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Here’s my progression:

A little over a year ago, I started building my Primo. I built it a little oversized because I had some specific projects in mind that required a somewhat larger build. As such, I ended up building for a 25" by 37" area.

This didn’t cause me many issues, although there have been some mishaps because of rigidity, which caused me to need to re-do some CAM and wasted some material. I did manage to get my large projects done, but then I wanted to be able to do some other things, and my Primo is generally too large to do it well. You may find that you have some of these things too with RC aircraft, where you want to do something like make aluminum servo blocks, or motor mounts. I don’t think you’d have any trouble with thin plywood reinforcing parts though.

So… I built a LowRider for larger cuts, and my plan is to reduce the overall size of my Primo to something that will be more rigid, in order to be able to handle other materials.

There are some things that I might recommend with cutting balsa wood.

  1. Most balsa that I’ve seen does not come in large sheets, but as boards. As such, a cutting area like 36" by 36" might not be necessary, and you might be better off looking at a smaller dimension. Say, 48" by 18" This will help a LOT with rigidity on a Primo, and should be absolutely doable. Good CAD/CAM should still allow you to make parts for up to 1/4 scale I would think.

  2. You might want to look into a vacuum table for hold-down. This will allow you to keep the parts in place without needing to clamp them. Even the painter’s tape and superglue trick could cause damage to something like balsa,which is not always particularly strong. A vacuum table works very well, and has the advantage that it can be turned off.

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Dan, thank you for the info! In terms of material, I’ll very rarely be using balsa. The planes I’m going to build will be made from composite (fiberglass) molds, and then I plan to use the CNC to cut things like internal wing ribs, fuselage bulkheads, etc. And since the planes will be fairly large (1/4 scale and bigger) that material will typically be both thick and thin hobby plywood.

I think I’m going to go a similar route as you, start out with the primo and maybe go smaller in size to increase rigidity and precision, and then if I feel like I need something to cut larger pieces (like spars and stringers) I can always build a LR.

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I have a Lowrider which can accommodate whole sheet material 1,25 x 2,50m.
The only thing is that you should consider ‘guides’ for the Y’axis. The hockey wheels will wander a bit. I had some aluminium rails just clamped to restrict the movement.
Currently I’m running on V-shaped wheels I printed, that seems to keep it in line as well.
Eventually, I consider to swich to SBR rails, as some others had done already.

I’ve only been using my laser for a few months, so others on this list will have more experience, but I’ve been having a great time with it. I have no trouble cutting 3mm plywood, though cutting speeds are 1/2 to 1/3 of what I could use with a router. Here is one one post by dkj4linux that outlines his experience cutting 3mm after upgrading to the A40640. While it will be slower, the things you get out of using it (vs. router) are:

  • Ability to cut fine detail
  • No need to design or cut “dog bones” in square pieces that fit together
  • “Finished” edges without worrying about tearout or splintering.
  • Ability to label pieces easily
  • Assuming your wood is relatively flat, no need for any clamping solution…just toss the wood on the bed.

As for what you will need in addition to a standard MPCNC/LowerRider build:

  • A laser mount to attach the laser to your Z axis.
  • A piece of sheet metal to protect the spoil board.
  • Something to lift the work off the sheet metal (aluminum honeycomb or some other form of mesh).
  • Air assist as outlined by Tom. I use an aquarium pump.
  • Fume handling as suggested by Tom (optional and depends on your situation).
  • I highly recommend the purchase of LightBurn ($60) as the software to drive your laser cutting.

As for setting off a smoke detector, I’m guessing it will depend on the detector. I’d guess it would set off one that uses particulates as a trigger, but it would not set off ones that uses IR unless the detector is poorly placed.

I run my CNC/laser in a well ventilated space but without any form of fume extraction. I don’t find the amount of smoke objectionable, nor the smell objectionable (too many years camping), but I do worry a bit since with plywood, I’m cutting glue as well as the wood, and I have no idea what kinds of chemicals the glue is putting off.

One thing I really like about the laser is how quiet it is. With the router, I confine my cutting to 10:30 am to 5:30 pm due to neighbors and members of my family. I use the laser whenever, including late and night and early in the morning.

Edit: And I wanted to mention, that if you are considering any laser engraving, and if you’ve not yet purchased your electronics, the SKR Pro is a somewhat better choice than the Rambo. If you are just cutting (laser or CNC), then either is just fine.