Precision Adjustable Z Endstop Holder and Constraint (Revisited)

thingiverse

A precision adjustable optical endstop holder for Prusa printers, with an integrated Z screw constraint bearing. I was finding that reaming out the slide hole could be quite a challenge, so I've incorporated triffid_hunter's bushing, to make things easier. I also added a matching Z screw constraint clamp for use on the other side of the printer. Instructions 1) Print. 2) Trim off the support inside the bottom nut trap. 3) Ream out the inside of the Endstop Mount/Glide's M8 hole, so that it runs smoothly up and down your Z axis smooth rod. Note: I've found that the knurled end of a narrow X-Acto knife handle (with the blade removed) is the perfect size for reaming out M8 holes. 4) Install a 608 bearing into the bearing cup. 5) Attach an optical endstop to the glide, using 2 M3 X 25mm socket cap bolts and nylock nuts. 6) Optionally, run an M8 or 5/16 nut partway up your Z axis screw. This nut will be used to secure the top of the constraint bearing. 7) Assemble parts onto the smooth rod as follows (top to bottom): a) Glide/Endstop mount. b) 3/8" I.D. x 51/64" spring. c) Clamp/Bearing mount. Note: you'll have to loosen your smooth rod, and slide it up out of its lower clamp, then re-affix it once the parts are in place. 8) Attach the Clamp/Bearing mount loosely to the smooth rod using 2 M3 X 20mm socket cap bolts and nylock nuts. 9) Assemble the adjustment bolt onto the assembly as follows (top to bottom): a) M4 x 40mm socket cap bolt. b) M4 washer c) Glide/Endstop mount. d) 11/64" I.D. x 5/8" spring. e) Clamp/Bearing mount. f) M4 nylock nut. 10) Move the clamp into its final position, and tighten the clamp bolts. 11) Optionally, secure the constraint bearing to the Z axis screw using 2 M8 or 5/16 nuts. 12) Assemble the matching axis stabilizer clamp for the other side of the printer. Vitamins: 2x - M3 x 25mm socket cap bolt. 4x - M3 x 20mm socket cap bolt. 6x - M3 nylock nut. 6x - M3 washer. 1x - M4 x 40mm socket cap bolt. 1x - M4 nylock nut. 1x - M4 washer. 1x - 3/8" I.D. x 51/64" spring. 1x - 11/64" I.D. x 5/8" spring. 1x - Optical endstop. I used a MakerBot endstop, but any optical endstop with 19mm mounting hole spacing should work. 2x - 608 roller bearing. Note: The springs I used came from a spring assortment kit sold by Home Depot - Everbilt #471864.