I developed these for my Biqu BX to space the gantry off the frame. These have a wide footprint to fit on the 40mm tube and a small square on top to rest the gantry on. The idea here is to level the gantry to the frame then level the bed to the nozzle. I went with a small square landing on the gantry to promote a level gantry- big flat sufaces invite tape and inaccuracy.
To use, have the gantry raised. Place a spacer on each side and by hand lower the gantry onto the spacers. I typiucally spn the couplers by hand by just running a few fingers across it, I do not grip the couplers. This allows a good feeling without clamping down on the spacers. Then start printer up and raise the Z gantry. When you raise the gantry the stepper is armed and will then hold position. After this I home, PLA preheat and do a manual bed level. I utilize Lukes Firmware, so the Z align and the probing is done at the start of the print every time (about 4-5 minutes).
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