Not that I want to encourage more dependency on printed parts but this seems like something higher performing and more easily printable and easy to manage than the herringbone: [pdf.directindustry.com] Could easily be a printable replacement for standardized nylon rack and pinion (which would be the boot strap option). https://reprap.org/forum/read.php?1,35898,35898#msg-35898 Sun, 11 Oct 2026 16:41:03 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,35898,36052#msg-36052 https://reprap.org/forum/read.php?1,35898,36052#msg-36052 Forrest Higgs General Sat, 13 Feb 2010 20:02:42 -0500 https://reprap.org/forum/read.php?1,35898,36032#msg-36032 https://reprap.org/forum/read.php?1,35898,36032#msg-36032 easier to print than a herringbone rack, it would require more non-printed parts. Even if it doesn't need bearings (which would require quite a bit of testing to determine, since you're talking about seeing how it wears down under longterm use), it does absolutely rely on precise and very stiff rods - ie, metal ones. A herringbone pinion has no need for metal elements - with proper design, even the shaft could printed.

I would also disagree that this design requires less printing precision than a herringbone gear. In order to maintain the high stiffness, high speed, and low backlash that makes it attractive, this design needs three of the rods to be engaged at any given time. That means the rods need to be precise as do their positions, and the rack also needs to be built to high tolerances.

If it turns out it does need a bearing for each rod, then I can't see any justification for it's use - you're talking about doubling if not tripling the number of bearings the whole design needs - the example pinion on page one would need 20 bearings alone! Needing to add 40 bearings (60 if you wanted to do the Z axis this way as well) is a major impediment in my book. By your pricing range, that's anywhere from $30 to $90 worth of (nonprinted) bearings.

By the way, chain and sprocket setups do involve rolling, they just don't have bearings at every joint. Which is why #25 chain isn't advertised as 0 backlash or having industry leading service intervals. Each link in the chain can rotate relative to the next around their shared post, which allows the post to rotate around the sprocket.

By the way, if you take away the bearings what you have is a very old technology called a cage gear or lantern pinion: [www.thefreedictionary.com]

One last note - according to that pdf, this design is patented.]]> Corwin General Sat, 13 Feb 2010 15:13:16 -0500 https://reprap.org/forum/read.php?1,35898,35996#msg-35996 https://reprap.org/forum/read.php?1,35898,35996#msg-35996 goinreverse General Sat, 13 Feb 2010 04:20:29 -0500 https://reprap.org/forum/read.php?1,35898,35995#msg-35995 https://reprap.org/forum/read.php?1,35898,35995#msg-35995 Triffid_Hunter General Sat, 13 Feb 2010 03:19:33 -0500 https://reprap.org/forum/read.php?1,35898,35994#msg-35994 https://reprap.org/forum/read.php?1,35898,35994#msg-35994 murd General Sat, 13 Feb 2010 03:09:46 -0500 https://reprap.org/forum/read.php?1,35898,35990#msg-35990 https://reprap.org/forum/read.php?1,35898,35990#msg-35990 goinreverse General Sat, 13 Feb 2010 01:26:02 -0500 https://reprap.org/forum/read.php?1,35898,35983#msg-35983 https://reprap.org/forum/read.php?1,35898,35983#msg-35983 murd General Fri, 12 Feb 2010 21:17:40 -0500 https://reprap.org/forum/read.php?1,35898,35982#msg-35982 https://reprap.org/forum/read.php?1,35898,35982#msg-35982 Triffid_Hunter General Fri, 12 Feb 2010 20:24:08 -0500 https://reprap.org/forum/read.php?1,35898,35951#msg-35951 https://reprap.org/forum/read.php?1,35898,35951#msg-35951 goinreverse General Fri, 12 Feb 2010 13:58:46 -0500 https://reprap.org/forum/read.php?1,35898,35944#msg-35944 https://reprap.org/forum/read.php?1,35898,35944#msg-35944
my 2ct]]> Anonymous User General Fri, 12 Feb 2010 13:11:56 -0500 https://reprap.org/forum/read.php?1,35898,35941#msg-35941 https://reprap.org/forum/read.php?1,35898,35941#msg-35941 Gene Hacker General Fri, 12 Feb 2010 12:05:05 -0500 https://reprap.org/forum/read.php?1,35898,35916#msg-35916 https://reprap.org/forum/read.php?1,35898,35916#msg-35916 [objects.reprap.org]]]> SebastienBailard General Fri, 12 Feb 2010 06:29:05 -0500 https://reprap.org/forum/read.php?1,35898,35915#msg-35915 https://reprap.org/forum/read.php?1,35898,35915#msg-35915 I think that I would use OpenSCAD to create a parametric model for this then you just specify the appropriate parameters and magic you have the proper STL file.]]> rhmorrison General Fri, 12 Feb 2010 05:48:06 -0500 https://reprap.org/forum/read.php?1,35898,35911#msg-35911 https://reprap.org/forum/read.php?1,35898,35911#msg-35911
Because the profiles are 2D for both the hubs and rack and the provided documentation lists dimensions it should be easy to build stl's for (rather than the herculean effort for the herringbone modeling)]]> goinreverse General Fri, 12 Feb 2010 05:00:20 -0500 https://reprap.org/forum/read.php?1,35898,35899#msg-35899 https://reprap.org/forum/read.php?1,35898,35899#msg-35899 Diary of a Technocratic Anarchist) is already working on this idea!]]> rhmorrison General Fri, 12 Feb 2010 03:01:33 -0500 https://reprap.org/forum/read.php?1,35898,35898#msg-35898 https://reprap.org/forum/read.php?1,35898,35898#msg-35898
[pdf.directindustry.com]

Could easily be a printable replacement for standardized nylon rack and pinion (which would be the boot strap option).]]> goinreverse General Fri, 12 Feb 2010 02:45:19 -0500