Using non hardened shaft for needle bearings 1

[SelfClinchBearings]

With our low speed and lighter loads, could we get by with unhardened shafts with your needle bearings?
Below are the specifics.

Bearing size: 5/8"
Life: 10 years
Expected hours running over 10 year life: 200 hours or less.
Speed: 30 rpm
Bearing load: 100 pounds or less 95% of life.
200 pounds 5% of life.

Thanks

Naveen

 

[unclesyd]

Wheelbarrow wheel needle bearings run on unhardened shafts and I have seen plain steel needles in the merchant grade models.
I wouldn't recommend running a needle bearing on an unhardened shaft. I think sone of the problems you will encounter is if the needles are hardened they will Brinell the soft shaft. The soft shaft will pick up and hold particles that will wear the hardened needle bearings. As you state long periods of idle is not good for lubrication of any bearing. If you are going to the trouble to make a shaft and not harden it you might try a preheat treated material, a step in the right direction.

 

[Hippo41]

For 10 year life expectancy you shoudl have a hardened and ground shaft at least.

Lester Milton
Telford, Shropshire, UK

 

[diamondjim]

You have not stated how soft or hard
that the shafts are. I would suspect
that your loads may be fine depending
if you have rubber tires on the wheels
to take any sudden or hidden shock loads.
I would submit your loads to a needle
bearing manufacturer with your shaft hardness
and ask him the expected life. I would
expect 1/12 the life of non hardened shafts
verses hardened. You could run a test in a
hurry by doubling the load during the test
condition and see if the results give you
the equivalent of 25 hours life. Then
examine the shaft and see how much wear you
have. The test would not be that hard
to do and you might want to test at least
5 bearings and shafts to get some reliable
information. Keep us posted!

 

[MASSEY]

Why use needles? Plain bearings made of engineered plastics can run on un-hardened shaft. just fine. They are inexpensive and can have PV values up to 53,000.

If interested I can provide links to suppliers and manufacturers.