PnP Head, Step 9: Place Z-low Limit Switch

take one M3-20 bolt (1) and push to it one M3 washer, one limit switch (note the orientation), another M3 washer (4), M4 nut (4) (used as a spacer) and one WSSB12-3-1 washer (6). The limit switch arm goes against the top side of the big pulley base. Attach the bolt to the lower one of the M3 extrusion nuts. Trim the position of the switch so that it easily clicks when the tube is pushed up, no matter where the tube is rotated and also releases reliably, with some margin. Don’t be too precise with this; You want a mm or two tube movement before the switch clicks. Tighten the bolt.

zbar step9

  1. M3-20
  2. M3 washer
  3. Omron D3V-162-1C4 limit switch
  4. M3 washer
  5. M4 nut (not M3)
  6. WSSB12-3-1 washer

Double check the operation: When you push the tube up, the switch should trigger first, then the bottom shaft collar (not shown on the drawing) should hit the bearing. When letting go, the tube should fall down under its own weight. Don’t have the belt too tight for this.

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