Precision Adjustable Z Endstop Holder and Constraint

by raldrich, published

Precision Adjustable Z Endstop Holder and Constraint by raldrich Feb 17, 2012
2 Share
Download All Files

Thing Apps Enabled

Order This Printed View All Apps


Liked By

View All

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag.

Print Thing Tag


Thing Statistics

10562Views 967Downloads


A precision adjustable optical endstop holder for Prusa printers, with an integrated Z screw constraint bearing.

I got frustrated with trying to adjust my Z axis endstop by sliding the clamp up and down the smooth rail, and found that the available designs for adjustable clamps wouldn't work for me, for one reason or another.


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.


2x - M3 x 25mm socket cap bolt.
2x - M3 x 20mm socket cap bolt.
4x - M3 nylock nut.
4x - 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.

Note: If you look carefully at the photo, you'll see that I didn't use #6/32 bolts and nylock nuts on mine, instead of M3, simply because that's what I had on hand. The .stl provided is sized for M3 bolts.

Note: The springs I used came from a spring assortment kit sold by Home Depot - Everbilt #471864.

All Apps

3D Print your file with 3D Hubs, the world’s largest online marketplace for 3D printing services.

App Info Launch App

Auto-magically prepare your 3D models for 3D printing. A cloud based 3D models Preparing and Healing solution for 3D Printing, MakePrintable provides features for model repairing, wall thickness...

App Info Launch App

Kiri:Moto is an integrated cloud-based slicer and tool-path generator for 3D Printing, CAM / CNC and Laser cutting. *** 3D printing mode provides model slicing and GCode output using built-in...

App Info Launch App
KiriMoto Thing App

With 3D Slash, you can edit 3d models like a stonecutter. A unique interface: as fun as a building game! The perfect tool for non-designers and children to create in 3D.

App Info Launch App

Print through a distributed network of 3D printing enthusiasts from across the US, at a fraction of the cost of the competitors. We want to change the world for the better through technology, an...

App Info Launch App

Quickly Scale, Mirror or Cut your 3D Models

App Info Launch App

3D Print a wide range of designs with Treatstock. Easy to use tools to get the perfect result. The global 3D printing network that connects you with high-quality and fast working print services nea...

App Info Launch App