MakerGear Forum

Check the endstops!! The M2 I am familiar with had been grinding gears from improper endstop positioning.
They can become contorted and bend, if this happens carefully (perhaps with needle nose pliers) bend the endstops back into a positon as where, once the bed plate hit them, you should hear/feel the contacts closing, and opening, in a clicking fashion. This seems to be a mildly common issue with a quick and simple solution that will save your motors and prevent anxiety levels from surfacing.
Hatter

New to printing with m2. i use S3d, are the end stops something i have to click on in the program? i've clicked on them before i think and i wasn't exactly sure what it was doing. i'm sure i did that part wrong. could i get some more info on how to use the end stops properly?

The end stops are the physical switches at the left of the X rail, rear of the Y rail, and top of the Z rods. They are what determine the 0/0/0 point for your print. The X and Y switches should not need any adjustment unless they become misaligned.

Still, be aware that the firmware is not always paying attention to the endstops. A print that attempts to go past the home position during a print is still likely to cause grinding, not to mention the fact that the M2 only has stops on the home end of each axis, not the other end. And the best thing you can do to prevent excessive grinding is to have a kill switch in easy reach, such as on a power strip next to the machine, or the remote switch that was mentioned in another post on the forum. A software kill switch generally does *not* satisfy this requirement, as a communications interruption can render the kill switch inoperable. That said, I've found the kill switch in S3D to be pretty reliable.

Just to clarify guys, that hideous noise when the stepper goes too far is just skipped steps, and is relatively harmless.

Define "relatively harmless". No, it won't burn out the motor, but it sure is shaking the heck out of the M2, not to mention ramming the endstops repeatedly, which is probably how they end up getting bent in the first place.

Well, relatively harmless means it's shaking the heck out of the M2 and potentially ramming the endstop (which is only an issue with X, the Y endstop has a nylon bump-guard) -- as opposed to slipping teeth on gears or shorting out motor windings, both of which are permanent damage. I can buy a 25-pack of (admittedly cheaper) leaf switches on eBay for $9 or so, I can't buy a new motor for $9.