Symmetrical compliant Z-coupler
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Published on December 21, 2012
Derived from
Symmetrical Prusa Z coupler
by triffid_hunter
Description
This coupler clamps directly to the lead screw, while also clamping to the motor via a rubber tube slipped over the shaft. This gives some tolerance to misalignment or bent screws without causing Z position errors like a springy helical coupler. It's just a tweak of Triffid Hunter's great iteration; in previous generations of the part, the clamping screws conflicted with the rubber tubing if the lead screw was smaller than the tubing O.D. This just locates the clamp screws relative to the larger of the tubing OD or the lead screw diameter, thus working with narrower screws (such as my 6.35mm ones) or thicker-walled tubing.
Instructions
Update: there was a missing semicolon in the original SCAD. It's fixed now.
Mine worked sweetly just as printed from the STL. If you have .250" (6.35mm) lead screws, chances are your local hardware store has inch size tubing, like mine. I used 1/4" O.D. x 0.170" I.D. vinyl tube which measured almost exactly 7 mm when snugly stretched the motor shaft.
Triffid Hunter suggests printing with 90% infill. I used PLA.
This really improved my bottom layers (and therefore prints) by making my Z zeroing repeatable. My cheap, easily bent lead screws are now a lot more tolerable.
Mine worked sweetly just as printed from the STL. If you have .250" (6.35mm) lead screws, chances are your local hardware store has inch size tubing, like mine. I used 1/4" O.D. x 0.170" I.D. vinyl tube which measured almost exactly 7 mm when snugly stretched the motor shaft.
Triffid Hunter suggests printing with 90% infill. I used PLA.
This really improved my bottom layers (and therefore prints) by making my Z zeroing repeatable. My cheap, easily bent lead screws are now a lot more tolerable.
License
Symmetrical compliant Z-coupler by bluecoast is licensed under the Creative Commons - GNU GPL license.
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As you'll see from my comment on triffid_hunter's version of this, the license is wrongly tagged on this item -- the copyright notice in the .scad itself correctly declares the license as GPL v2 or later, so perhaps you'd be kind enough to fix the way that's been tagged in thingiverse so that it also shows as GPL
It's changed to GPL now -- forgive me!