Moskito's Lowrider Build

Now that I’ve got my Lowrider moving under its own power I figured I’d share.

Its running on the Rambo board with 87oz steppers and the dual endstop firmware. For now the endstop switches are dangling in the air until I can figure out where I want to mount them and print make some mounts. Its a 28" x 51" cutting area with a welded steel frame. Currently I have it sitting on sawhorses until I fabricate some folding legs. My plan is to hang it from the rafters. Its X axis tubes are 1.25" OD. A lot of parts had to be “reverse engineered” and changed to allow this and I have no clue if the changes were worth the effort. I’ve only just tried the Crown Test. I’ve got great plans for this sweet machine like cutting new flat parts out of aluminum that I’ve got and once figuring out THC, getting my plasma cutter and a water table on it.


First Cuts, a sign for the dogs toy area. I’ve got a lot of learning to do, but boy am I ecstatic about his.

Pretty good, a Vbit is very unforgiving so that is a very solid first cut!

Something is a bit off, I can’t tell what, but boy is it close. Your build just proved itself. Congrats.

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Good to know, I used a 1/4" 45 degree cheap harbor freight bit.

As far as switching my z axis motors from running in series to running on two separate ports on the rambo board, wouldn’t I go about it by plugging the z motors into what is labelled as X1 and X2 in this photo? And if so, how would I swap the x axis and z axis in the firmware, software or gcode?
Right now the ports labelled z in the photo are the actual z.

Using dual drivers doesn’t give you any practical advantages over serial when you’re not using dual endstops. The reason Ryan and I worked all that through is to get dual endstops, which will measure the position of each motor and when homing and allow them to adjust to square. That was all for the MPCNC. I do think dual Z and dual Y endstops would be beneficial on a low rider. The thing is though, it’s really easy to square a 5’ long gantry. So, basically, I think it makes more sense to just wire them in series.

But it can be done. Marlin is going to use the extruder drivers from X2,Y2,Z2. In that order. So if you disable X2 and enable Z2, E0 will become Y2 and E1 will become Z2. It should be as simple as removing DUAL_X_MOTORS and enabling DUAL_Z_MOTORS.

Dual endstops on Z are tough on the low rider because you don’t want the gantry to sit on the endstops, so you’d want them on Z max. That becomes another issue because Zmin logic will still exist. So you have to use something like Z max and Y max for the z endstops. I’ve written it up before and I think two people have said it worked for them.

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Sounds like ill eventually wire up the y endstops and ditch the z. Now as far as using dual drivers, is there a potential for the motors to have more holding power vs wired in series? If not then I’ll stick with the wiring I curently have in use, but if there is some extra holding power to be gained then I figured it would be worth the extra work to do it.

And knowing the dual endstops was a little more specific to the mpcnc makes everything make so much more sense to me.

You shouod get the same amount of holding power in series or separate drivers. Parallel is splitting the current between two motors, so it’s effectively halved.

After sorting out the dual endstops, cutting woods, plastics and making aluminium chips, I’d like to start figuring out how to get my plasma cutter working on it.

Can Mach3 be used with this system? Has anybody figured out a way to implement THC? Better yet a working arduino based THC? Should I start a new thread in the hardware dev, troubleshooting or advice forums?

There are a couple of posts about plasma cutting. There are a couple of posts about mach3 (a long time ago). AFAIK, no one has combined them with these machines. I had to look up Torch Height Control (THC). Looks like it uses some special hardware to measure the cutting distance and adjust the height with that feedback?

There’s nothing to stop you from using Mach3 with these machines. If you can figure out the THC stuff, or even just setting up Mach3, I would be interested in reading about it (and I’m sure I’m not alone). You can post it here or a thread in the software development section.

I would probably suggest looking at the other plasm builds which didn’t need the THC and I’d start with doing the physical alterations necessary for plasma first. Once I had a torch cutting thin stuff, I’d look into THC and do Mach3 only if I had to.

After working on a different CNC machine, I’ve considered trying to use Mach3 and a Gecko driver for the stepper motors. Mach3 required quite a bit of setup, but once everything was dialed in, it ran pretty smooth. The Gecko board made adding end stops easy. The problem is, you’d be looking at $300-$400 just for the software and driver.

Have you had a chance to rig it up to the rafters yet? I’m in a similar situation - kit has been ordered and I’m working on the table.

Do you have any more detailed shots of the framing of yours? Or the rafter attachment method?

Looks like a really clean set up, I’m using it as my guide.

I finally got around to getting my plasma torch mount made. It has a z limit switch built in and will also allow me to use a standalone torch height controller to move the stepper mounted on top of the mount. Now I need to figure out the controller side of things. How do I go about adding an on/off relay? How do I go about wiring the Z Probe switch if I already have dual Z endstops? How do I get the machine to probe the surface before initiating a cut? Lastly, how do I get the machine to turn on the plasma cutter, but not move until an arc okay signal is established first? The arc okay signal will be a simple open/closed reed switch. Thanks for the help.

Also if there are any good resources with using the lowrider as a Plasma machine please direct me to them. I’m having a tough time finding answers.

P.S. I haven’t gotten around to building the table lift for my rafter stowaway table is not a finished project and I want to know its final weight before designing the system.

Photos of finished mount to come.

I am interested in your table as well. Is that 2 or 3" square tubing? I have a friend here at work who is a great welder this could be a route I would look to take! Love the thought of just being able to slide in a new 4x8 of plywood for a new spoilboard a year down the road and have a nice steel table to push around the shop. Any other info would be greatly appreciated! Any pics before the spoilboard was thrown down?



I dont have photos of table before spoil board went down, but I used 2" and 1 1/2" square tube and 1/2 mdf. Eventually down the road I’d like to replace the spoil board with a 1/2" aluminum fixturing system and when I want to do through cuts I can put the MDF board on top. The machine has more than enough rigidity to deal with the extra 1/2" in Z height.

On another note, wondering the best way to have both dual z min endstops as well as a z probe. I figure that I could either have the z probe switch control a DPDT relay for the individual Z endstops, or… Would it be possible to use the Zmax enstop to when “true” then Z1min=true and Z2Min= true?

Am I overthinking this? Is it possible to have both dual z enstops with a z probe? Is it possible to have the machine home or probe before initiating each cut via the fusion post processor? Is the post-processor able to request an arc ok signal prior to each cut?

I can cut without any of these features, but these would take the machine to a level comparable to a lot of the sub $5k plasma cutters out there, add a THC and it could probably compete with an $8k-$12k table.

I may be on the cusp of barely being able to understand whats going on in the fusion post processor. I looks like I am able to push a G30 command before each cut for touch and go probing. For waiting for an Arc OK signal, I may be able to use an M109 command directly after each M3 and either plug a switch into the thermistor port, or use my Zmin and do some changes in firmware.

Now is there any reason why people are using M106/107 vs M3/5?
Ideally, Id like to save the M106/107 functionality in case I want speed control later.

I am interested in the parts you modified for the 1.25" x tubes and if you would be willing to share the STL / DXF files. I was planning trying to accomplish this myself.

I may be convinced to share the STL files, if Ryan is doing the convincing. And I definitely wont share the CAD files ever. Im not super comfortable with sharing the stl files cuz there are a lot of parts that dont work exactly as intended and support for people when they have problems might be a little difficult for everyone who is trying to help. Also, im using a mixed bag of V1 parts, V2 parts and my 1.25 parts. If Ryan wants the headache of trying to help troubleshoot a machine he didnt design then I could be convinced.

Update, I was unable to figure out how to write a fusion post processor. Instead I made a couple macros in excel to find and replace commands with what I wanted. So I’ve got “Touch and Go”, Pierce Delay, Pierce Height,and Cut Height all working. I still need to figure out how to disable the hotend in firmware before I can use an M109 command for the Arc OK signal. That can wait. Next is building the water table then finally cutting some steel.