How to fix failed zero calibration and stuck hex nuts

[sujitvasanth]

I was nearlyin tears when my beloved Elgoo Mars failed to zero and made grinding noises at the build plate.
Sometimesthe plate is at an angle where the lcd touches the plate before it gets to the end-stop.
The resisitance casuses the lowering mechanism to grind noisily and you cannot zero the endplate.

You need to make sure that the hex screws are copletely loose so the buid plate is able to use the spring inside itm and reach the end-stop.

THe hex nuts for the build plate dont match the hex spanner supplied exactly and conseuqetly after a while the front hex nut will not turn with the hex spanner supplied Use a custom microscrewdriver with the apropriate bit to overcome this - this is often the original cause fo the zero calibration failure..

[cliffyk]

I was nearlyin tears when my beloved Elgoo Mars failed to zero and made grinding noises at the build plate.
Sometimesthe plate is at an angle where the lcd touches the plate before it gets to the end-stop.
The resisitance casuses the lowering mechanism to grind noisily and you cannot zero the endplate.

You need to make sure that the hex screws are copletely loose so the buid plate is able to use the spring inside itm and reach the end-stop.

THe hex nuts for the build plate dont match the hex spanner supplied exactly and conseuqetly after a while the front hex nut will not turn with the hex spanner supplied Use a custom microscrewdriver with the apropriate bit to overcome this - this is often the original cause fo the zero calibration failure..

Hex socket set screws (even big ones) have suffered from this failure for years in all sorts of applications--I.e. they suck, I stopped using them on anything I designed 50 years ago.

Elegoo abandoned them on the Mars Pro, and i believe no longer ships them on the Mars (my M20nnn series unit received in May of this year came with Hex socket cap screws.

My recommendation to anyone is that if your Mars still has the silly socket set screws go to nearly any hardware store and buy a couple stainless steel M6 x 8 (or even 10 mm) socket cap screws, I prefer the slightly longer ones, and toss the socket sets in the trash

Hex Socket Cap Screw:


To do it 100% correctly grind/sand a "ball" nose on the screws before use...