I am trying to use linear bearings Lm8uu on my x axis smooth rods. They slid very rough by themselves and are very hard to move when attached to the x axis base plate. The rods are imp and measure 7.65mm not chromed. Any suggestions how to make them slide smoother? https://reprap.org/forum/read.php?151,153212,153212#msg-153212 Fri, 10 Jul 2026 21:53:28 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?151,153212,157522#msg-157522 https://reprap.org/forum/read.php?151,153212,157522#msg-157522 BAMCNC General Mendel Topics Fri, 28 Sep 2012 19:36:40 -0400 https://reprap.org/forum/read.php?151,153212,157287#msg-157287 https://reprap.org/forum/read.php?151,153212,157287#msg-157287 How are your prints?
With a rough x I don't get good precision.
Any thoughts on bronze / brass bushings]]> Fri General Mendel Topics Thu, 27 Sep 2012 22:44:01 -0400 https://reprap.org/forum/read.php?151,153212,156001#msg-156001 https://reprap.org/forum/read.php?151,153212,156001#msg-156001 xiando General Mendel Topics Sat, 22 Sep 2012 12:16:51 -0400 https://reprap.org/forum/read.php?151,153212,155980#msg-155980 https://reprap.org/forum/read.php?151,153212,155980#msg-155980 It is worse now then with the 5/16" rods.
Any ideas?]]> Fri General Mendel Topics Sat, 22 Sep 2012 09:59:43 -0400 https://reprap.org/forum/read.php?151,153212,153824#msg-153824 https://reprap.org/forum/read.php?151,153212,153824#msg-153824
I agree. there's too much play and the bearings can''t seat properly, leading to slide rather than roll. One could argue that he could get away with the printed bearings, but I don't want this to devolve into a specious debate.

"and is in fact higher tolerance than what most people use."

yup. I'm fully aware of the difference. Sorry, I was trying to be tongue-in-cheek regarding the "you must" comment accompanied with a very specific part number, but perhaps a bit too dry about it... There is no "must" aside from 8mm smooth rod (not btw limited to steel rod with certain restrictions) and a particular persons' expectation of performance and operating environment, in part only limited by available kitting.]]> xiando General Mendel Topics Tue, 11 Sep 2012 12:28:20 -0400 https://reprap.org/forum/read.php?151,153212,153712#msg-153712 https://reprap.org/forum/read.php?151,153212,153712#msg-153712
looks like you have the more expensive, 'harder' version, of 8mm stainless rod. you should be fine. you could save a few dollars ordering the other part number.

biggest issue i would see is trying to use 5/16 with 8mm bearings. Even with 8mm rod, my ebay bearings aren't exactly smooth as silk.]]> slauziere General Mendel Topics Mon, 10 Sep 2012 23:44:58 -0400 https://reprap.org/forum/read.php?151,153212,153709#msg-153709 https://reprap.org/forum/read.php?151,153212,153709#msg-153709 -------------------------------------------------------
> ooh...did I purchase the wrong rod then? I didn't
> bother with the annealed variety, considering the
> low expected loading, and just purchased the
> McMaster part #3180T14 to save a few dollars. Bad
> choice, or negligible difference?

If that's the part number you purchased, you spent a lot more than you really needed to. But the part number you listed will work perfectly fine, and is in fact higher tolerance than what most people use.]]> NewPerfection General Mendel Topics Mon, 10 Sep 2012 23:36:52 -0400 https://reprap.org/forum/read.php?151,153212,153688#msg-153688 https://reprap.org/forum/read.php?151,153212,153688#msg-153688
"You must"]]> xiando General Mendel Topics Mon, 10 Sep 2012 20:54:58 -0400 https://reprap.org/forum/read.php?151,153212,153544#msg-153544 https://reprap.org/forum/read.php?151,153212,153544#msg-153544 Fri General Mendel Topics Mon, 10 Sep 2012 09:00:39 -0400 https://reprap.org/forum/read.php?151,153212,153248#msg-153248 https://reprap.org/forum/read.php?151,153212,153248#msg-153248 bearings. (McMaster Item 88625K67 - 3' lengths)

In the US McMaster-Carr on www.mcmaster.com is a good source
for the Metric rod: pick a distribution point nearest you. I used eBay
for the bearings, with free shipping from China/Hong Kong.]]> Scrachbuilder General Mendel Topics Sun, 09 Sep 2012 00:21:47 -0400 https://reprap.org/forum/read.php?151,153212,153228#msg-153228 https://reprap.org/forum/read.php?151,153212,153228#msg-153228 NewPerfection General Mendel Topics Sat, 08 Sep 2012 21:02:57 -0400 https://reprap.org/forum/read.php?151,153212,153219#msg-153219 https://reprap.org/forum/read.php?151,153212,153219#msg-153219 They feel worse on the base plate because you get the combined resistance and it's unlikely the rods and bearings are accurately aligned.]]> Polygonhell General Mendel Topics Sat, 08 Sep 2012 19:31:05 -0400 https://reprap.org/forum/read.php?151,153212,153212#msg-153212 https://reprap.org/forum/read.php?151,153212,153212#msg-153212 They slid very rough by themselves and are very hard to move when attached to the x axis base plate.
The rods are imp and measure 7.65mm not chromed.
Any suggestions how to make them slide smoother?]]> Fri General Mendel Topics Sat, 08 Sep 2012 18:57:35 -0400