a few questions. and endstops again

hi all

I have started to build my first mpcnc. mostly all parts have been bought, including 710W 43mm metabo router. it will be mpcnc with 600x400x140 mm work area based on stainless steel 25x1.5 mm tubes. plastic is pla. general usage of the cnc will be milling, may be later I will also buy laser head. I have no plans to use it as 3d printer at the moment.
I’m familiar with 3d printing, marlin firmware and made a 3d printer. but in cnc i’m newbie.

  1. Am I right if I think that usually entire gcode for milling generated by cnc related software is in relative coordinates. So milling will move from the point when I run the gcode.

  2. I have readed a few threads here about end stops. Ryan said that 99% of work could be done without endstops (so I may not install them?).
    But the same time he said that firmware will not allow to moving to negaive direction without homing axis (it’s true) and of course homing require end stops.
    It’s a bit confusing )
    How cnc could work in endstopless mode?
    Probably this is possible when all defines of endstops are commented in the firmware?

  3. But I think that probably I will build it in dual endstops configuration. Which design is better
    this modern https://www.thingiverse.com/thing:2847042
    or this “classic” https://www.thingiverse.com/thing:1023985 ?
    Modern looks pretty, but probably more reduce working area then classic. Also modern has more long wiring which is moving. And may be both endstops in the classic could be adjusted more precisely to each other (in modern a block can be set only by step of the belt, 2mm).

  4. Should I setup Z-max endstops (classic I guess)? Is it need for milling or laser cutting?

  5. I printing all parts from PLA, but for 43mm router adapter I think it would be better to use petg because it could be warm.

  6. I had make a little mistake when bought the router. It has safety protection in the electronic module. It doesn’t turn on after I connect it to an outlet until I explicitly turn it on it by the switch on the body. Could it be a big pain if i will have to turn it on manually every time before milling? I’m afraid that may be I will make a small moving at the start point even is stepper motors will be powered on.


1- It can, or it can be absolute.

2- You are mixing up two conversations. If you use endstops for obvious reasons you can not go in the negative direction. Start without them.

3- Neither interfere or reduce your work area. If you use my kit it is wired for the “modern” one. The classic, was for those that insisted on endstops pre-dual endstop firmware. I do not recommend them.

4- Nope, a touch plate is more appropriate for milling.

5- It shouldn’t get that warm. If it does try PETG, depending on the design PETG can be way more flexible than you think.

6-No, you should be turning it on and off manually. We typically do not automate that. Do not leave your machine unattended even for a second. right now on the social page there is a mpcnc fire video linked.

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Thanks, Ryan

1-3. I think I will try to comment out all #defines related to endstops and will see how this will going on. May be I will also play with repetier.
Also I will print parts of “modern” design and install them. If I will need endstops - I just will mount and wire them.

  1. Do you mean a metal plate located on just the table aside of detail which connected to ground and a wire connected between metal part of the router and Z-min?

  2. I just aftraid that aluminim part of the router which also holds a bearing coild became too hot for PLA (over 60C) during a long milling. Router weight is 1.4kg.
    I have found 2 designs for 43 mm
    This looks obsolete https://www.thingiverse.com/thing:1610485
    I guess this is ok https://www.thingiverse.com/thing:1037598
    If it’s not ok I will make my own.

  3. Ok. I just made assumption that when I will turning it on I may reduce accuracy of starting point.
    That’s router:
    [attachment file=67070]
    [attachment file=67071]

hi again
i had downloaded all 3 ramps related firmware.

  • ramps old “no endstops” (it seems obsolete, marlin 1.1.0)
  • ramps “no endstops” (marlin 2.0) from github
  • ramps “dual endstops” (marlin 2.0) from github
    I had looked into them and I think that now I understand how homing works in mpcnc

If i got it right:

for “no endstops” the configuration defines hardware XYZmin endstops, but defines all endstop signals as inverted. so whenever I will try to make homing - firmware will act like all endstops immediatelly are pressed and the home will be at the current position.
the configuration defines default bed as 200x200, but supresses software endstops for both XYZmin and XYZmax. so the cnc could move above max and below min.

for “dual endstops” configuration defines hardware XYZmin and XYmax(used as X2min, Y2min) endstops, but inverts only Zmin. so there is performed real homing for XY and fake for Z.
the configuration defines default bed as 200x200, but supresses software endstops only for XYZmax.
and of course this variant of firmware uses E0/E1 drivers for X2/Y2 motors.

both firmwares define fake termistor with stable temp 170C

i think that it’s easy to make hybrid version which will be “no endstops”, but will use E0/E1 drivers for X2/Y2 motors. just in case if I will want to have ability to fastly switch “no endstops”/“dual endstops” without change connection of the motors .

No, you simply do not home. Home is right were the head is when you boot up.


Z is set for a touch probe, very real.


Why? If you have it wired just use them. The only added step would be a work offset added to your Gcode/CAM.

I see. So i just have to manually move to start point and then turn on the machine