How can you say they will heat up if you don't know what speeds are being used? At what speed will a 6002 2RS C3 "heat up"?

the rubber seal is in contact and so friction results in heat. That is whyall spindles have some sort of Labyrinth seal setup

Then why do HSD use a sealed bearing at the top, and why do I have a sawdust problem with the Fimec spindle that has an extensive labyrinth seal setup and no seals? Please believe me that 6002 2RS C3 would be the most sensible choice in our case.

I am just giving you the theory behind the reasoning for the selection of bearings used in different applications. a 2RS will heat up more than a ZZ but the 2RS does give a better seal. That is why most high speed applications have bearings with out covers.
I have found the best type of seal for enviornments which are very dusty is a thing called a FEY ring.

The last photo above shows "FEY" rings

Gerald, Port is right rather use an open bearing or ZZ the 2rs is a much tighter seal and will heat up. Thats if you are going to try and use a cheepie. As I say to my customers you get what you pay for.

Andy and Port, if I follow your logic, there is no application where a 2RS bearing should ever be used, and that they should stop the production of it. You are also saying that HSD, who produce fine spindles, are making a mistake when they use a small diameter 2RS bearing at the back end of their spindles.

You seem to be missing the fact that we talking of a 15mm ID bearing, which can easily handle 15 000 rpm in 2RS format, and that we very rarely run our spindles over 11 000 rpm. After seeing sawdust get past the "FEY" labyrinth rings and damaging the Fimec's open bearing, as well as having seen sawdust get past the Z shields of our stepper motors, as well as knowing our HSD spindles are trouble-free with 2RS bearings, I think I am making a pretty informed decision to use 2RS bearings at the small back end.

The big front end is another matter entirely. That bearing is 35mm ID and a contacting seal (2RS) will be no good at 11 000rpm.

I think you guys are generalising too much, and not considering the diameters and speeds of rotation.

Point taken on the id but I always stick to the basics like you do when doing wiring. If you have poor extraction dust will get anywhere not evenn the man upstairs can stop that. The fact is that a 2rs will generate more heat than a zz, heat causes bearing failure so asto at what RPM this failure is going to take place who knows, but we do know that the spindle will get hotter with the 2rs, fact.
Maybe the manufacturer hald less comebacks with the better sealing of the 2rs than the zz.

Gerald I always put a little grease on the fey rings stops more dirt and runs better on start up.

Gerald,
How much life did you get from the cheapo bearings?
Also, the top bearing, is it just a standard bearing? My supplier lists ceramic skf's at this size, or would replacing with a P4 bearing be a good idea?

Just curious,

R

The repaired spindle with the cheapo bearings hasn't seen any service yet.

The top Fimec bearing appeared to be a standard 6002.C3 (open, extra clearance). HSD said they use 6002.2RSL.C3 which also is a common standard bearing. Realise that these are small diameter, low load bearings, and thus I don't feel the need to go for expensive bearings there. (They are also easy to replace).