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We all know (or should!) that the repeatability of common spring-arm limit switches is crappy at best. I'm looking to build & install one of the precision height adjusters for the Z-axis limit switch, and noticed a post on some forum suggesting removing the arm and triggering the switch button directly (e.g. with a screw end).

Has anyone tried this, and if so has the repeatability of Z-homing improved any?

Edit

Sorry -- this is a stock Prusa i3, which depends on physical contact between the vertically-moving subassembly and a microswitch mounted on the frame.

1 Answer 1

The answer to this question is, no, taking the lever off will not do anything improve repeatability, but it will improve accuracy of the Z Axis. I have tried both ways, actually 4 with a Duet Wifi. 2x 8mm Leadscrews, 0.9 Stepper, Calibrated at 800 Steps per MM.

  1. Full lever size: After actuation I have to baby step up my Z Axis 13 x 0.05mm to let go, and then 13 of the same baby steps back down to actuate it.

  2. Short lever: After actuation I have to baby step 0.05mm 10 times, 10 more times to let go.

  3. Small enstop button only: 3 x 0.05mm baby steps is all that is needed.

  4. Larer button from roller lever endstops: 10 x 0.05 baby steps needed both ways.

The large endstop button only surprised me, thought it would be more reliable.

It is a bit more difficult to make the small button approach work, and it will increase the likelihood for failure and machine damage though.