6204-2RZ Bearing question

[Dennis Peacock]

I have a 1 HP slow speed bench grinder that is making bearing noise. I finally got it apart and the bearings on each end of the shaft are 6204-2RZ bearings. It seems easier to find 6204-2RS bearings than it is to find 6204-2RZ bearings. I've tried making sense of the markings and what they really mean but I'm a bit more confused now than I was when I started this search for bearings.

Can I use 6204-2RS bearings or do I need to get an exact replacement bearing (6204-2RZ)?

[Ken Combs]

RZ is a 'partial seal' , non contact. RS is a rubber seal. I'd use RS.
Lots of info here:
https://www.skf.com/us/products/rolling-bearings/ball-bearings/deep-groove-ball-bearings/designation-system

[Jerry Bruette]

2RZ means a shield on each side of the bearing, 2RS means a seal on each side. The 6204 is the bearing series and size. You're good to go with either the RZ or RS.

[Dwayne Watt]

RZ is a rubber non-contact seal. This is different than a shielded bearing. A shielded bearing has a barrier of steel or composite material that only "suggest" materials stay separated from the balls and raceways. Non-contact seals are seals with very light contact between the rotating members or a labyrinth type seal with zero contact (grease is part of the sealing structure). Non-contact seals have lower drag (friction) losses but are not as robust as standard contact seals in terms of keeping contaminants away from the bearing balls and grease. Contact seals run a bit warmer as result.
All that said, 6204-2RS will be just fine for the application.

[Bill Dufour]

Speed below 5,000 rpm, RS is is better in most applications.
Bill D

[Dennis Peacock]

Thanks everyone! Then 2RS it will be.

[Bill Dufour]

Save the old ones to make tools to push in the new ones. Grind the od down just a touch. Then remove the inner race and heAt it red hot and allow it to air cool. Then drill it just a fraction large.
BILL D.

[William Lessenberry]

Dennis, Motion Industries in Little Rock is a Timken dealer if you want to drive down here. (501) 568-3116 (https://www.google.com/search?client=firefox-b-1-d&q=Motion+Industries+little+rock#)
BillL

[Bill Dufour]

Get them from the bay or amazon, under $10 for a pair. No need for precision name brand in this application. Save a long drive to a real bearing supply house.
One of the two in my town disappeared. That one never had it in stock anyway. AHd to come back next day to pick it up.
Bill D