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Topic: When is Backlash "Good Enough"?

It would be helpful if we all had an accurate universal way to compare our backlash.  I use a dial indicator mounted horizontally.  Then I run the carriage a few mm into it in one direction, zero the reading, go another 10 or 20 mm, and return to the first measurement point.  The difference between the readings is the backlash in that axis.  Currently, my Y-axis is around .1 mm and my X-axis is around .05mm.

I think that is pretty good, but I'd like to do better.  My Y-axis was consistently at .19mm until I switched to a direct drive which brought it to .1mm.  Obviously, I recommend that mod.  It took almost .1 mm of backlash out.

Where is the remaining backlash?  I already have linear bearings on everything.  I am unsure about going to GT2 belts because people have reported mixed results.  I just ordered F686 ball bearings to replace the bushings on the Y axis rod (not installed yet).

What I want to know from others is what is your current backlash in each axis measured with a dial indicator?  Also, which mods showed the most decrease?  Chasing backlash could go on forever so I'd like people in this forum to share what they've been able to achieve so we can know when enough is enough!

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Re: When is Backlash "Good Enough"?

I haven't measured mine in a while, as I'm waiting to replace a wobbly x-motor carriage before getting into it. I suspect it's a bit awful right now from the print quality.

Your method is right, and your numbers sound quite good, I remember getting about 0.1mm in each axis after direct drive.

Unfortunately we're usually a bit excited about mods so don't really verify them particularly objectively. Also, when taking the printer apart for one reason it's tempting to change a few things while you're there...

That said, I too would be interested to see people's measured results. Get your dial indicators out and let's see who's got the best numbers. smile

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi