Added info on Vermeer 630A pillow block bearings
Just wanted to throw in my two cents which might help someone else. I recently acquired a 630A which needs bearings. After a lot of time pondering what to use, I ordered bearings from my Vermeer dealer at $120 each.
Yes, spherical bearings are probably superior and not that much more ($220 above vs. $120 isn't that bad considering the labor involved to replace!), but it didn't appear sphericals would fit a 630A (at least mine) without modifications to the mounts. In fact, a lot of generic pillow blocks have a longer body than fits my 630A--use caution before ordering!
According to parts info my dealer sent, the Vermeer bearings were spec'ed as P3U228HM which are Link-Belt (Rexnord) ball bearings with a "floating labyrinth seal" (H suffix). Not sure what M suffix means.
I had a hard time finding a matched set of similar quality bearings on ebay for much less money, especially with a labyrinth (non-rubber) seal. I decided it was worth it to just order dealer parts. I'm hoping I don't receive Chinese junk substitutes! Note the parts sheet lists them with a modification, which I think is milling/grinding the ends so they fit between stop blocks. I will post again once I see them.
Incidentally, spherical bearings are capable of much higher loads than ball bearings (~10x), but most catalogs I look at don't show 1500-1600 rpm as unreasonable speed for ball bearings. With 2:1 belts and a VH4D, my cutter must run about that rpm.
If you're trying to use generic pillow blocks with rubber seals, you might try pressure-limiting grease fittings to avoid blowing them out. McMaster.com has them. Only problem... they are large. I'm thinking button-head grease fitttings on my bearings (again McMaster), as it seems regular fittings will get knocked off in no time!
Note: I'm probably going to post some comments on belts and pulleys elsewhere if you are searching parts for a 630A.