Dual motor carriage

New Home Forum LowRider Troubleshooting – LowRider Dual motor carriage

This topic contains 11 replies, has 5 voices, and was last updated by  beetlejuice0331 4 weeks ago.

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    My Y-axis is skipping steps (611 carriage).  I only have one stepper rated at 1.4A with the driver voltage at 0.8V.  The driver voltage was initially set to 0.65V but after modifying to 0.8V it did improve somewhat.  I also replaced the driver to no avail.  Here are my ESTLCam settings.

    • 1/8″, 1/16″ mill bit
    • F(xy)=8mm/s -15mm/s
    • depth 5.2mm w/1mm Z steps
    • Rapid xy 2100
    • Rapid z 480

    The LR is square, it can go across the entire workpiece (XY) without issue, and it’s powered off of a 10A power supply.  The project will start out fine but after ~5min the y-axis begins to skip.  For example, it will cut the first pass but starts to skip on the second pass when its half way through the first y-axis side of the square.

    Should I increase the driver voltage?

    Is a matching stepper necessary?




    Slow your XY rapids, make sure your drivers are staying cool, 0.8V can be really toasty on some DRV8825’s A fan is a must above 0.7V.

    Is your bit dull, new, burnt? If you are always  cutting at 1mm DOC than the first 1mm might be dead. It is preferable to cut deeper and slower, make sure your RPM is appropriate, I usually run it at about a 3 on the 611 dial with a single flute bit at 5-10mmDOC in real wood at about 8mm/s.



    Look for misalignment too. If it’s on the second pass, it might be trying to cut 10mm instead of 5mm. IIRC, that’s what lead me to install my “hack tracks”. You can also test in foam, which might show any misalignment, but it should not skip steps in foam.

    My y has either skipped steps because I was asking too much, or it stopped completely when it overheated. I don’t know if it will over heat, skip a few, and then continue.



    I had a similar problem, it disappeared after I upped the driver ref. voltage, installed a 12v fan over the drivers and used a new bit. In hindsight I think I would have been better configuring the XY rapids..

    I also loosened the bearings on the 611 Carriage – I’m interested to get Ryan’s take on this;

    I loosened the bearings until I could spin the bearing without the 611 Carriage moving, or the bearing sticking, I’m not sure if this is how the machine is designed to move, but after doing this, moving the carriage with the steppers disengaged by hand it did seem to move a lot more smoothly.

    Another thing I did was to set the offset of my top height to +2mm, my table and material varies up to 2mm difference, this means my initial cut would be between 3-5mm and not a possible 5-7mm.. the proceeding cuts are then all 5mm.

    To complicate things further – I noticed that the connection to my X Axis Stepper is slipping out every so often, I’m thinking of securing the cables into the connector with a bit of plastic epoxy.



    Holy smokes 5-10mmDOC… single pass?!  What do you set the XY rapids to?

    I tried a new 1/8″ and 1/16″ two flute flat nose bits on RPM-6.

    There is a fan directly over the drivers.

    I ran the gcode w/o the router and there are skipped steps.

    For the attached image, you can see that the bit got through a couple of layers of ply.  The cut was going from the right to the left.




    A two flute bit should be spun as slow and moved faster or they tend to burn. Single flute really work nice.

    gcode w/o the router and there are skipped steps.

    That is a major problem, don’t bother making cuts until you figure this out.



    Pictures? Make sure the bottom wheels are super loose, they can pinch and stall the machine. They almost are not needed.



    Correct me if I’m wrong, but it’s not the whole carriage that’s stalling, it’s the plate on the tubes, right? The roller wheels shouldn’t matter. Also any goofiness in the alignment shouldn’t matter either.

    Some easy stuff to check:
    – make sure your pulley isnt slipping
    – make sure your wiring is secure
    – make sure there isn’t anything binding there

    After that… Hmmm. Tough one. You could take the motor off the belt and run the gcode again. If it still fails, it’s nothing mechanical. I’m not sure if you’d be able to tell if it’s not moving though.

    You could also try swapping motor drivers or motors. But try the easy stuff first.



    Ohhhh, sorry I didn’t pay enough attention. Make sure it isn’t hitting wires or zipties on the aluminum v channel.



    Adding a second motor to the carriage and lowering my speeds resolved the issue.


    Axel Kingsley

    What speeds did you end up using? I’ve got another motor on-deck for the same issue (haven’t installed it yet), and I’ve been running at Ryan’s suggested maximum most of the time.


    • Rapid move from G00 to G01
    • Rapid feed XY-1500 and Z-80
    • 1/8″ 1 flute DOC-5mm, XY feed-7mm/s, Zfeed-1.5mm/s, Spindle Speed-3.5(DW611)
    • 1/8″ 2 flute DOC-1.5mm, XY feed-15mm/s, Zfeed-1.5mm/s, Spindle-2
    • Material- Pine, poplar, cedar

    It seems conservative but so far it has been reliable.

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