Material for Thomson linear bearing? best- 316, 304, 303, carbon steel? to worst?

[rons]

Here is the bearing and they have customers who purchase carbon steel shafts.

https://www.grainger.com/product/THOMSON-Linear-Pillow-Block-Bearing-2HXW8

The 303 I have looks like rough aluminum and since I don't use it much it could be polished up
and used for rails. This is for a sliding table in wet conditions. Will 303 be better than carbon steel?
I know I could use 304 or 316.

 

[Milland]

For any real wet use, you'll want something like hardened and ground 440C stainless steel. Soft stainless, like 3xx, would not hold up, nor give good performance.

Keep in mind that "regular" linear bearings are usually 52100 bearing steel, which rusts like a bastard at the least provocation. There are bearings also made from 440C, but mucho dinero. You may want to use polymer bearings on 440C rail (or in that case, even 316 G/P) for decent life.

 

[DavidScott]

Some linear shafts are ground type 3 anodized aluminum. Igus is one supplier.

 

[rons]

The pillow blocks I have are not ball bearing. There is a bronze bushing inside for sliding and adjustment screws on the aluminum body.
This is the closest I could find. A plastic piece version. My pieces don't have any identification. They were taken off another sliding table from the 90's.

https://www.grainger.com/product/2LFH8?gucid=N:N:PS:Paid:GGL:CSM-2295:4P7A1P:20501231&gclid=EAIaIQobChMI1MGZq9W4_QIVAhbUAR0vEgYcEAQYBSABEgIrF_D_BwE&gclsrc=aw.ds

I have seen and own sliding tables that are just steel on steel. For woodworking tables and tile saw tables.
The bronze bushing type was not found in my search. I think it's a good choice for sliding tables that are not in a clean friendly environment.

It doesn't help by looking at all the motion control stuff these days. Lots of choices, from cheap to big dollars.

 

[Milland]

I'd still look at polymer bearings in this application, on 316 or whatever ground rails. Should be lower friction and last just fine in a wet environment as long as there's not lots of abrasive dust involved to get entrained in the water.

If for abrasive use, get the hard 440C or ground hard anodized Al rails.