Where to buy smooth rods and bearings
So it looks like I'll have to replace at least one of my X-axis smooth rods (it has wear tracks) and my bearings. What's a good place (besides Prusa) to buy these items? Where do I find the specs for them? Are there better bearings to buy than what came with the original printer (I hear about people recommending misumi bearings sometimes)?
Thanks a lot.
RE: Where to buy smooth rods and bearings
I purchased a set directly from Misumi, But I think they are available for a bit less from places like All3D.
Specs? Who needs specs!
LMU8 is about all you need for bearing specs. Rods and 8 mm x length: and it's best to measure the ones you have. Three lengths: 320, 330, and 370 - but verify first.
https://us.misumi-ec.com/vona2/detail/110300026540/?HissuCode=LMU8
RE: Where to buy smooth rods and bearings
And shafts: https://us.misumi-ec.com/vona2/detail/110302634310/?CategorySpec=00000042688%3a%3aa
ps: you want hardened material, but the sky is the limit for other treatments like chrome and machine tolerance.
RE: Where to buy smooth rods and bearings
Thanks. Wow, the Misumi stuff is a lot more expensive than Prusa:
Stainless steel rods: $18 each from Misumi vs. $10 for a set of 2 (or $25 for a full set of 6) from Prusa
Linear bearings: $6.50 each from Misumi vs. $14.30 for a set of 10 from Prusa
It's not that much money if I just replace my 2 rods and 3 bearings, but I'd like to order spares in case any of my other axes start to show problems. That's $173 for a full set from Misumi and $40 from Prusa.
Is the Misumi stuff really significantly better? Is it worth it?
RE: Where to buy smooth rods and bearings
Prusa rods are not stainless; they are simple hardened steel. And most folk that use Misumi rods buy their hardened steel versions. So perhaps you are looking at higher end versions of the bearings, like you are the rods.
My last order from Misumi was under $200, and I bought high precision rods and bearings with stainless retainers. So not sure what you are looking at.
Anyway - buy what best suits your needs.
RE: Where to buy smooth rods and bearings
Stainless steel bearings / rods are usually softer than hardened steel so will wear quicker, the advantage they have over hardened steel is that they are more resistant to corrosion in wet environments.
As long as you lubricate your bearings beforehand and wipe a thin film onto hardened steel rods, you will not get any corrosion in most home environments, so you are better off with hardened steel rods and bearings for a Prusa printer.
In both cases stainless and hardened you MUST lubricate the bearings when assembling else they won't last long.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
RE: Where to buy smooth rods and bearings
Me, being cheap:
If I had a rod with wear tracks, I would rotate it to an unused portion and replace the bearings. Only works once - then too many tracks.
Rod only wears where you see the track. Rest of the rod is like new.
RE: Where to buy smooth rods and bearings
@robert-rmm200
I actually did rotate the bearings on the X-axis rod, but didn't change the bearing (didn't have a spare set) and now I have 2 wear tracks on my rod. So... I need a new rod. 🙂 I decided to order the Prusa rods and bearings this time around and see how they last once I properly lubricate them (unlike I did the first time).
RE: Where to buy smooth rods and bearings
Yeah - as you discovered, bad bearings wear new grooves really quickly...
For a hobbyist, I would expect new rods and properly greased bearings to last at least a year, maybe two.
We have some commercial users; I would be surprised if theirs last over 6 months.
I would love to hear how much life Joan gets out of hers...
RE: Where to buy smooth rods and bearings
@robert-rmm200
I have more than a year on mine but its printing almost every day. No sign of damage I am contemplating an upgrade for Misumi rod and Bearing. The y axis have to much play for my taste (not that i see direct problem, but from a mechanical point of view). Anyone with those or similar care to share if it improve there print ? Assemble with Grease and Clean/ re-grease every 6 months or so they should be good for a while....
- 10x LMU8 Misumi
- 2x PSFJ8-320
- 2x PSFJ8-330
- 2x PSFJ8-370
RE: Where to buy smooth rods and bearings
@frank_the_rock
What did you end up doing here? Was thinking about an order direct from Misumi as well.
RE: Where to buy smooth rods and bearings
Two or more years ago Tom Sanlanderer tested his Prusa rods on camera and discovered that they hadn't been hardened. I think maybe it was his live build of the I3 MK3? Prusa was watching the broadcast and said he would send Tom new ones, that a few unhardened ones had somehow slipped through. Presumably, by now, this has been sorted. So, just saying, given the difference in price, maybe you'll want to try Prusa again.
Anyhow, unless I'm mistaken, Thomson Industries is another common "go to" place for high quality rails and bearings. I can't say for sure how they compare to Misumi, but I'm guessing about the same(?) since both have datasheets and specs. Both have a series of youtube videos explaining their wares.
Of course, you could also try aliexpress roulette. I got chromed hardened steel rods from there for my chinese CNC, and they have worked out much better than the originals.