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Mounted sleeve bearing selection

jscpm

Titanium
Joined
May 4, 2010
Location
Cambridge, MA
In choosing off-the-shelf, pillow block style sleeve bearings, I am a little confused why the bearings with the apparently better specs are cheaper.

For example, at McMaster some of the choices for 5/8" mounted sleeve bearings are as follows:

Dry Acetal 5202N14, radial load 95 lbs, price $20.39
Babbit 6359K13, radial load 145 lbs, price $68.63
Oil Embedded 5912K6, radial load 850 lbs, price $20.51
High-Speed Oil Embedded 3813T12, radial load 1550 lbs, price $10.25

So, as the radial load capacity increases, the bearing type generally gets cheaper and cheaper! In my application the journal is a shaft that has a grinding wheel mounted on it running at 1750 RPM doing form grinding on a die. So, in my case maybe I want the Babbit after all because it is fixed alignment, so I will get a more rigid wheel. The other bearings are "self-aligning" so they could potentially move more I guess and result in more vibration in the wheel, which would be undesirable.

What are some of my design considerations here when choosing between these bearing types?
 
Jscpm, I have a crate full of premium pillow blocks, various bearing types (ball, sleeve oilite,) that I can turn loose of that would hopefully keep you from having to buy import. Send a PM when you get a chance.
Johnny
 
After looking at the items in their links, I figure that the cost is based on the how the housings are made. Two are machined out of solid aluminum, one is an iron casting with machining, and the cheap one is stamped and spot welded steel.
 
After looking at the items in their links, I figure that the cost is based on the how the housings are made. Two are machined out of solid aluminum, one is an iron casting with machining, and the cheap one is stamped and spot welded steel.
Yes, I get that, but why would a person pay 6x more for a part with an inferior radial load spec? Obviously there must be some desirable feature that the higher priced item has, otherwise it would not be in the catalog.

In the grand scheme of things, however, the price issue is just a curiosity. I really want to know what considerations I should be making in selecting between the options.
 
In choosing off-the-shelf, pillow block style sleeve bearings, I am a little confused why the bearings with the apparently better specs are cheaper.

For example, at McMaster some of the choices for 5/8" mounted sleeve bearings are as follows:

Dry Acetal 5202N14, radial load 95 lbs, price $20.39
Babbit 6359K13, radial load 145 lbs, price $68.63
Oil Embedded 5912K6, radial load 850 lbs, price $20.51
High-Speed Oil Embedded 3813T12, radial load 1550 lbs, price $10.25

So, as the radial load capacity increases, the bearing type generally gets cheaper and cheaper! In my application the journal is a shaft that has a grinding wheel mounted on it running at 1750 RPM doing form grinding on a die. So, in my case maybe I want the Babbit after all because it is fixed alignment, so I will get a more rigid wheel. The other bearings are "self-aligning" so they could potentially move more I guess and result in more vibration in the wheel, which would be undesirable.

What are some of my design considerations here when choosing between these bearing types?
None.
Pick a ball bearing.

BTW your cheapest one is used in squirrel cage HVAC blowers, and you want to doo precision grinding with it ???
 








 
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