Material for large pulley

JPMacG

JPMacG

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I'd like to make a new pulley for the counter shaft of my lathe. The pulley is 9 inches in diameter and has two sheaves.

My question is what to make it from. Searching online, it seems that the two most economical options are 6061T6 aluminum and grey cast iron. Either would cost around $60 for a 9 inch diameter 1.5 inch thick piece. Is there another option that I should consider? Of course, I would like something less expensive.
 
Would it be any cheaper to make it in two pieces from 3/4" plate?

David
 
I'm with Randy on this one . I had a job way back making large pulleys in my first shop , way too large to plunge with a form tool . Ended up plunging with an Iscar carbide parting tool and then doing a lot cranking on the compound which was not fun . Seems to me buying one would be the cheaper solution . But hey , the fun is in the making !
 
If you NEED to make one, do the aluminum, it would have less inertia, faster starts faster stops, if that is an issue, also, cast iron, which I dearly love, is less apt to run balanced than aluminum. That being said, buying one MAY be cheaper.
 
You can get a 9" dia. by 1.5" thick piece of 6061 from online metals for around $50.

For a less expensive alternative, you might look at casting your own blank. A foam pattern could be made and the lost foam process used for casting. If you wished, you could use Zamak for a lower the melting point. When I used to cast Zamak, I got my metal from old automotive castings but it is used in a wide variety of products.
 
benmychree said:
If you NEED to make one, do the aluminum, it would have less inertia, faster starts faster stops, if that is an issue, also, cast iron, which I dearly love, is less apt to run balanced than aluminum. That being said, buying one MAY be cheaper.
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If I had to make one, I would consider the heavier weight a benefit. Especially with an low powered unit. Inertia is like horsepower, it helps you get through the parts on flywheel . it also creates an even speed for the spindle, which leads to smoother cuts.
That would be my opinion.. But AL is much easier to work.
 
JPMacG said:
I'd like to make a new pulley for the counter shaft of my lathe. The pulley is 9 inches in diameter and has two sheaves.

My question is what to make it from. Searching online, it seems that the two most economical options are 6061T6 aluminum and grey cast iron. Either would cost around $60 for a 9 inch diameter 1.5 inch thick piece. Is there another option that I should consider? Of course, I would like something less expensive.
Click to expand...

A bit more on the Zamak. It's melting point is about 700ºF, similar to lead, and its density id about 7 g/cc or about the same as cast iron. Zamak is an aloy consisting primarily of zinc, with aluminum being the major alloying metal at around 4%.

To make a simple disk would require around 25 lbs of metal. That could probably be cut in half or better with a pattern more closely resembling the final shape. I

f I were doing it, I would make the pattern of two stacked disks slightly larger in diameter than the final dimensions.
 
The surplus center, has some 3 grove pulleys in 8&3/4, or 9&3/4", that you might be able to use.

I made a large serpentine belt pulley for a pump, out of a weight lifting barbell weight. Made the bore fit a split bushing hub that I had. The weight did not matter to me, but one could take a bunch of the weight off the center if it needed to be lighter.
 
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