Torque needed to turn steel shaft

[alliedcp]

Hello,

My mind has drawn a blank. I need to determine the necessary torque turn a steel shaft. The shaft is 7" in diameter, 36" long, and weighs approx. 400 pounds.
What torque is necessary to start from a stand still. I only want it to turn at 15-20 rpm.

 

[Hush]

You need only enough to overcome your friction, after that any additional will increase your acceleration (decrease your ramp up time).

 

[JayMaechtlen]

so, what kind of bearings?
that will determine static friction (stiction?) and dynamic friction.

is the shaft connected to anything? if not, why bother?

has your brain unstuck yet?

;-)

Jay

 

[alliedcp]

Thanks for your response.

Well my brain has partially unstuck. I am trying to make a polishing stand for large shafts. I am going to use heavy duty casters inverted with the work piece resting on top of them. I will be driving 1 of the 4 wheels with a belt pulley setup connected to a motor/reducer. The bearings of the casters are roller bearings.

I think I will need approximately 300 in/lb torque.

 

[JayMaechtlen]

sounds reasonable.

what will you use to do the polishing?
will it impose a torque on the shaft?

(I hope you have some kind of lift to load/unload those 400 lb shafts!)

Jay

 

[alliedcp]

We will be using emory cloth to polish the shafts. They don't need an exceptional amount of clean up just enough to bring them back to as new condition.

Yes we do have a 5 ton over head crane for use in loading the polisher.

Ken