Rack and Pinion for X-Axis Based on [www.thingiverse.com] I built a replacement for the belt on the x-axis of my Prusa. As Triffid Hunter suggested in his comment, I used a small pinion instead of the big one. The result looks like this: mod_embed_images_loadimage('5420daa797beeeab6081043189a0381c', '/forum/thumbcache/e49/7c9/d5e/584/0af/d4b/ad3/437/aae/5e3/49_800x400.png', 'http://forums.reprap.org/file.php?255,file=7417,filename=prusa-mendel-xrack-pinion.jpg', 'https://reprap.org/forum/addon.php?1,module=embed_images,check_scaling=1,url=http%3A%2F%2Fforums.reprap.org%2Ffile.php%3F255%2Cfile%3D7417%2Cfilename%3Dprusa-mendel-xrack-pinion.jpg', '', 130192, 800, 400, 'Loading image ...', false); Today I tested it: I observed no backlash. Next I will replace the y-belt. https://reprap.org/forum/read.php?1,130192,130192#msg-130192 Wed, 07 Oct 2026 18:31:26 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,130192,166188#msg-166188 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,166188#msg-166188 miso General Wed, 14 Nov 2012 20:17:13 -0500 https://reprap.org/forum/read.php?1,130192,166147#msg-166147 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,166147#msg-166147
good point,

wonder why they did that? Do the large machines use this method? They claim this design comes from their experiences with the larger equipement.]]> Prober General Wed, 14 Nov 2012 16:01:10 -0500 https://reprap.org/forum/read.php?1,130192,166105#msg-166105 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,166105#msg-166105
@idolcrasher: I bought a set of 200 different springs on ebay.]]> theodleif General Wed, 14 Nov 2012 11:34:45 -0500 https://reprap.org/forum/read.php?1,130192,166101#msg-166101 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,166101#msg-166101
[www.kickstarter.com]]]> Prober General Wed, 14 Nov 2012 11:13:10 -0500 https://reprap.org/forum/read.php?1,130192,165821#msg-165821 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,165821#msg-165821 Idolcrasher General Tue, 13 Nov 2012 02:02:34 -0500 https://reprap.org/forum/read.php?1,130192,161890#msg-161890 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,161890#msg-161890
I love the rack and pinion idea. I have not rally seen this explored any further yet in the wild.]]> Idolcrasher General Sun, 21 Oct 2012 01:40:30 -0400 https://reprap.org/forum/read.php?1,130192,150321#msg-150321 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,150321#msg-150321
]]> theodleif General Sat, 25 Aug 2012 03:53:38 -0400 https://reprap.org/forum/read.php?1,130192,131818#msg-131818 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131818#msg-131818 The solution I came up with was to use a spring loaded rubber coupling. Basically a tight fitting X coupling with rubber in the middle. The problem was the software had to account for it. It took to many steps to get it moving. And every direction switch required a pause to let the rubber decompress. The final solution ended up being a ball screw that was pretensioned. So a true 0 backlash system. The X coupling could work well for this and take some of the shock out of start and stops. Something like this. [www.lovejoy-inc.com]]]> tjhj2 General Mon, 07 May 2012 22:54:05 -0400 https://reprap.org/forum/read.php?1,130192,131661#msg-131661 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131661#msg-131661 www.youtube.com]
It was setup where you could pull the platform all the way out which was pretty nice for access when removing prints.]]> billyzelsnack General Sun, 06 May 2012 23:33:22 -0400 https://reprap.org/forum/read.php?1,130192,131655#msg-131655 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131655#msg-131655 gtg252b General Sun, 06 May 2012 21:37:02 -0400 https://reprap.org/forum/read.php?1,130192,131366#msg-131366 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131366#msg-131366
I can easily see a different printer design where the motor moves rather than the rack being a much closer basis for a fully printed printer minus electronis.
great work.]]> fyrebug General Fri, 04 May 2012 14:15:31 -0400 https://reprap.org/forum/read.php?1,130192,131356#msg-131356 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131356#msg-131356 -------------------------------------------------------
> Very interesting. Have you needed to lower your
> acceleration?

I should, because the printer tries to jump off the table.]]> theodleif General Fri, 04 May 2012 12:17:12 -0400 https://reprap.org/forum/read.php?1,130192,131355#msg-131355 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131355#msg-131355 -------------------------------------------------------
> Do you use lubrication on the racks?

No.]]> theodleif General Fri, 04 May 2012 12:07:44 -0400 https://reprap.org/forum/read.php?1,130192,131351#msg-131351 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131351#msg-131351 Pointedstick General Fri, 04 May 2012 11:11:26 -0400 https://reprap.org/forum/read.php?1,130192,131341#msg-131341 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131341#msg-131341 rigid chain actuator, so that the footprint of the printer is the same as with belts.]]> Buback General Fri, 04 May 2012 09:51:03 -0400 https://reprap.org/forum/read.php?1,130192,131317#msg-131317 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131317#msg-131317 evilb General Fri, 04 May 2012 04:59:55 -0400 https://reprap.org/forum/read.php?1,130192,131236#msg-131236 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,131236#msg-131236
]]> theodleif General Thu, 03 May 2012 14:56:51 -0400 https://reprap.org/forum/read.php?1,130192,130436#msg-130436 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,130436#msg-130436 -------------------------------------------------------
> could a person try switching it to, m4 threaded
> rod to save on mass or is there another reason
> that you would want to use that heavy threaded rod
> still.?

In rack_herringbone.scad, line 16 you find: innerRadius=3.1;//shaft radius, in mm.

Just change the radius to the value you need.]]> theodleif General Fri, 27 Apr 2012 15:42:58 -0400 https://reprap.org/forum/read.php?1,130192,130429#msg-130429 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,130429#msg-130429 -------------------------------------------------------
What's the maximum speed you can
> achieve reliably with your X axis now?

100 mm/s. Still improving. The pinion stops much harder than a belt. But I it seems to be very accurate.]]> theodleif General Fri, 27 Apr 2012 13:39:58 -0400 https://reprap.org/forum/read.php?1,130192,130364#msg-130364 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,130364#msg-130364
Unfortunately for me I'm getting in on RepRap a little later, and I'm still waiting on the rest of my parts to arrive before I can make one.

One thing that I was thinking about though is durability. I plan to maximize speed, accuracy, and repeatability with my machine, and so if at high speeds I'm wearing down a printed rack or gear really fast, then that would be a problem. Keep us updated! What's the maximum speed you can achieve reliably with your X axis now?]]> pwn4 General Fri, 27 Apr 2012 00:38:18 -0400 https://reprap.org/forum/read.php?1,130192,130356#msg-130356 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,130356#msg-130356 dissidence General Thu, 26 Apr 2012 19:31:26 -0400 https://reprap.org/forum/read.php?1,130192,130203#msg-130203 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,130203#msg-130203
Even 64 mm/s works accurately:

]]> theodleif General Wed, 25 Apr 2012 15:10:00 -0400 https://reprap.org/forum/read.php?1,130192,130199#msg-130199 Re: Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,130199#msg-130199 NewPerfection General Wed, 25 Apr 2012 14:47:28 -0400 https://reprap.org/forum/read.php?1,130192,130192#msg-130192 Rack and Pinion for X-Axis https://reprap.org/forum/read.php?1,130192,130192#msg-130192 www.thingiverse.com] I built a replacement for the belt on the x-axis of my Prusa. As Triffid Hunter suggested in his comment, I used a small pinion instead of the big one.

The result looks like this:



Today I tested it:



I observed no backlash. Next I will replace the y-belt.
]]> theodleif General Wed, 25 Apr 2012 14:11:54 -0400