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Old 05-20-2010, 10:24 AM
5-7HEAVEN 5-7HEAVEN is offline
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Join Date: Aug 2008
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Default Fitting A 1/4" Pulley Onto A 1/2" Shaft

I have a 4" jackshaft with 1/2" diameter, spinning at 10,000rpm. The aluminum belt pulleys I need to use are about 1" outside diameter with .25" bore diameter. The hub diameters range from .512" to .787". The pulleys are secured onto the shaft by two #8-32 setscrews.

I have been unable to find correctly-sized steel pulleys which could be bored to 1/2" and welded onto the shaft.

The 1/2" shaft is supported by bearings at each end. The pulley will be situated 1" from the outboard bearing.

How would you suggest installing a 1/4" bore aluminum pulley on a 1/2" steel shaft?

Should I bore the pulley hub to 1/2", then slip it onto the shaft? In one case, the hub diameter will only be .012". No hub support at all.

Do I machine the shaft down to .25" bore, 1 1/2" on the outboard end? I could then slip the pulley onto the shaft. Then I would have to find a 1.375" bearing with .25" inside diameter.

FWIW, the aluminum pulleys are only $6.22; the shaft is $40. The machine shop will probably stiff me to resize the shaft.

Thanks for any help.
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