So I’ve got my Stop blocks on the conduit, but I’m really not sure where they are to be placed? I am also unclear as to where the endstops are to be actually mounted on the MPCNC Primo. I have gone through the instructions multiple times. I see where it says you pop the stop blocks on, but not with a defined location in mind. For example, does it need to be up against the corners or spaced out a little bit? And where do the Endstops go? Do they mount on the stopblocks or is there another location?
See the last pick on the Trucks page. You’ll find two small holes on the underside edge. The stop blocks go on the conduit between the 0,0 corner and the end stop on the truck.
I found that my stop blocks needed to be about 45mm from the corner in order to keep the core from hitting when I had a tool mounted in it. If you are using dual end stops you will need to adjust their positioning in order to square things up.
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Ah, thanks so much for that! So, I’m still not quite understanding what the Stop blocks actually do. Are they supposed to be the trigger for the endstop as well as placed in a precise location in order to square the machine on top of stopping the tool mount from running into itself?
If you are not using the limit switches for auto-squaring, you would hold your axes against the stops when you power on your machine. This way it starts and stays square. At least until your steppers de-energize😉
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Are they supposed to be the trigger for the endstop as well as placed in a precise location in order to square the machine on top of stopping the tool mount from running into itself?
Squaring the machine is their primary value. The core hitting the trucks, while producing an ugly sound, will do little or no damage. Personally, I mounted my stop blocks so that when the core hit the trucks, the switches were triggered but not smashed. You can adjust for squareness by either moving the stop blocks, or by using an M666 g-code command.
Note an overwhelming majority of MPCNC users (running Marlin) set the origin of a cut relative to their stock. This is done using a G92 g-code command when the router is positioned at the stock origin. When you execute a G92, your machine is no longer “homed,” and therefore the end stops are no longer active to prevent “crashes” during your job. Your machine will remain square as long as the steppers are energized.
Edit just to be clear, end stops are never active during cutting, but if the machine is in a “homed” state, it will not process negative coordinates and therefore will not try and go beyond the home position.