When you say the spindle drops, are you referring to the z-axis assembly that contains the spindle? If so, did you replace the lead screw and anti-backlash nut with a ball screw? Ball screws have extremely little friction and will cause an assembly under gravity to move down. If not, your lead screw and anti-backlash nut friction is extremely small, which is surprising and I have never seen this before. I would be interested in seeing a picture of the assembly. Please send a picture to techsupport@buildyourcnc.com so I can investigate this issue further.
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We haven't replaced or disassembled anything on the z-axis. I will try to get some photos sent to you. Are there any adjustments or recommendations for PM of the z-axis assembly?
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Can you tell me what PM means?
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The spindle drops on our greenBull when power is turned off. How do we stop this?