On Thu, 14 Jan 2010 19:03:03 -0800 (PST), mark
wrote:

On Jan 14, 12:37*pm, Ned Simmons wrote:
On Wed, 13 Jan 2010 18:42:34 -0800 (PST), mark
wrote:

I want to mount a 2' long 1.5" shaft with 2 pillow block bearings but
I would also like to have a thrust bearing because the shaft will have
a load from one end. I assume this is not good for the pillow block
bearings. How do I go about this. Can you buy off the shelf thrust
bearing assemblies the way pillow block bearings are sold? *Thanks

Normal ball bearing pillow block bearings can carry thrust loads. If
the thrust is less than 20% of the dynamic load rating of the bearing
you probably don't have to worry. If it's more than that you should go
thru the procedure in the bearing mfr's catalog to calculate the
equivalent load using your anticipated radial and thrust loads.

You can get tapered roller bearing pillow blocks, but they're larger
and much more expensive.

When applying thrust loads to a pillow block you do need to consider
the strength of the housing, its mounting, and the means for
transferring the thrust between the shaft and bearing.

How much load, radial and thrust, are we talking about?

--
Ned Simmons

I did some checking and it seems the HC208-24 bearing that these
pillow blocks use have a dynamic C load rating of 30000 (N) and a
static Co load rating of 20000 (N). What does this mean?

C is the load that 90% of the bearings in a sample will support for 1
million revolutions before failure. Life and load are linked by an
inverse 3rd power relation. In other words, if you reduce the load by
half, the life will increase 8 times. (2x2x2=8)

Co is the load that will permanently deform the bearing some very
small amount. I don't remember the amount off the top of my head.

30000N equals 6700 pounds force.

--
Ned Simmons