Machining a Pulley for a Drill Press

Searcher7 · 2011-02-16T06:42:57+00:00

I decided to get back to putting together an old table top drill pressthat had never been used. I proceeded to connect the AC and the pulleyto the motor shaft, only to find out that the pulley has an I.D. of1/2" and the motor shaft has O.D. of 5/8". (This explains why theprevious owner never finished it).Outside of trying to find another pulley set I was wondering if Ishould look into machining the present motor pulley by boring the1-1/2" I.D. long from 1/2" diameter to 5/8" diameter.Also, the pulley has a set screw, and the motor shaft has a key-way.The problem is that the set screw *may* be too small for the key-way,in which case I'd also have to re-drill for a larger set screw.And all this after I figure out whether this would be best done on alathe or a mill, and then how to work hold for both operations.I'd appreciated any advice on whether a project like this isplausible, or should I just keep my eyes open for a pulley set thatfits.Thanks.Darren HarrisStaten Island, New York.

Feb 16, 2011 52 Replies

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Jim Wilkins 9 years ago

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I printed and laminated a spreadsheet showing the RPM and cutting speed in SFM of common tool diameters for the six belt positions on my Clausing. Its designer chose 180, 350, 600, 1000, 1900 and 3250 RPM.

It's usually at 600 RPM which is slow enough to cut mild steel with up to 1/2" tools and not too inconveniently low for shallow holes with small bits. 180 RPM allows flycutting cast iron and hole saws up to 2" (with the belt loosened), 3250 RPM is good for milling narrow slots in aluminum. S&D drills from 9/16" to 1" run at 350 RPM. It's a real 700 Lb milling machine but I use it mostly for drilling.

--jsw

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whit3rd 9 years ago

You probably want a second and third drill press, actually. Spindle speed is very important sometimes.

Winding springs, all five speeds are too fast. Putting an 0.040" hole in chrome-nickel superalloy, all five speeds are too slow.

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Jim Wilkins 9 years ago

Does 4130 Prehard count?

--jsw

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John B. 9 years ago

I added an additional "idler" pulley to one drill press that multiplies the number of speeds. See

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which is quite useful.

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Jim Wilkins 9 years ago

On my Clausing the intermediate pulley shaft slides and clamps in a tee slot, which might be easier to retrofit than a pivot shaft but is difficult to adjust because it tilts from free play when loosened and tightening the clamping knob on top pulls it upright and changes the belt tension.

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--jsw

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jamesjaddah1755 9 years ago

Ok, obviously the more steps the better.

But are there any foreseeable problems using a 1/2" chuck pulley and a 5/8" motor pulley in the drill press?

Thanks.

Darren Harris Staten Island, New York.

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jamesjaddah1755 9 years ago

I settled on a 5=step aluminum pulley for the motor.

Thanks.

Darren Harris Staten Island, New York.

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Larry Jaques 9 years ago

So, did you end up turning it yourself (more satisfying) on a lathe or did you buy one (less satisfying), Darren?

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jamesjaddah1755 9 years ago

Actually I won one on Ebay:

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Darren Harris Staten Island, New York.

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Larry Jaques 9 years ago

IOW, you bought one from an eBay vendor for $20.80. OK.

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jamesjaddah1755 9 years ago

It was actually the cheapest 5-step pulley on Ebay. :-)

Darren Harris Staten Island, New York.

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Larry Jaques 9 years ago

Yeah, that wasn't too bad a price. But "won" sounded like you got a freebie. How's it working?

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jamesjaddah1755 9 years ago

I did get another tool with it from the same seller.

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Darren Harris Staten Island, New York.

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