Pulley Fun
February 5th, 2009Nothing Matches
Man, it’s impossible mating motors to drive pulleys.
Here’s what I have. I can get a nice motor with a 7/8″ shaft. But the best drive pulley I’ve found is right here. As you can see, it has a bore larger than 7/8″.
I guess this would be a big ol’ joke to a person who owns a mill and a lathe. You pop your metal into the lathe, make yourself a cylinder that fits around the shaft, and then mill a keyway in it. For that matter, I guess you could make the pulley itself, with the right size hole.
Irritating.
I’ve had other ideas. One is to get a go-kart drive wheel with a 5″ diameter and weld it inside a piece of steel pipe with a 5″ ID. The pipe wouldn’t be crowned, but I have a theory about that. You put it on the motor, bolt the motor down, fire it up, and put a crown on it. You use the motor as a lathe to turn the pulley while you shape it. Would it work? I’ll never know, unless a source of 5″ ID pipe falls into my lap. I think go-kart wheels would be good for idlers, because the bearings are made to put up with high speeds and heavy loads over long periods of time.
The idler pulleys are not a problem, regardless. I can get 4″ belt sander pulleys and bearings cheap. If they’ll work on belt sanders, surely they’ll work on a grinder. The big challenge will be to get them mounted right.
February 5th, 2009 at 7:28 PM
I’m starting to think that the reason that people use V-belt pulleys is to overcome the shaft issue (instead of for torque/speed reasons).
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How long is the shaft on the motor? Maybe someone can cut a 5/8″ hole in a 1-1/2″ shaft for you (see McMaster PN 1497K172).
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If you’re looking at Kart Parts, have you looked at BMI?
http://www.bmikarts.com/index.htm
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My son wants to build a go-kart this summer.
February 5th, 2009 at 9:21 PM
Why not buy a piece of shaft stock that is keyed and of the proper diameter for the old drive pulley, then power it with a very short 1 to 1 ratio V belt drive with the motor mounted parallel to the secondary shaft?
This arrangement would also let you experiment with pulley sizes (sheeves in technical terms) if you needed to slow things down instead of using the variable frequency drive. Of course you could still use the VFC just for fun.
BTW If you never have used a belt sander (I can’t remember if you did the tool purchase adventure) you need to know that the fine adjustment of the angle of the belt idler and drive is critical to keep the sanding belt from “walking” off sideways and possibly breaking and flying at your private parts at high velocity.
February 5th, 2009 at 9:30 PM
I hate pulleys and belts.
February 5th, 2009 at 9:32 PM
Okay, how about a 5″-O.D. steel tube. 12″ costs about $26. See T2W5120 at:
http://www.metalsdepot.com/products/hrsteel2.phtml?page=rndtube&LimAcc=$LimAcc
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Weld on two 1/8″ end-plates, drill center holes and weld in a 5/8″ shaft and you’re most of the way there. After that you’ll need bearings and a shaft coupler.
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As to the go-kart wheel; sorry, I didn’t see anything with a 5″ I.D.
February 5th, 2009 at 9:39 PM
That’s probably a good way to go. I crawled all over that site, but I don’t recall finding the relatively cheap tubing.
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I’ve noticed that some flat belt pulleys just have a plate on one end. I guess you can get away with that if the pulley and shaft are strong.
February 5th, 2009 at 10:12 PM
“I’ve noticed that some flat belt pulleys just have a plate on one end. I guess you can get away with that if the pulley and shaft are strong.”
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I don’t know how much tension your putting on it, but if the bearing is close to the ends of the tube, it shouldn’t matter too much.
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You’ll also need to make sure you can adjust the “angle” of the pulley…similar to what tread mills do. It’s probably easiest to do this on the non-driven roller. Maybe you could mount the bearings in the end-plates (on the non-driven roller) and use the shaft with some bolts on either side to adjust the position of the roller?
February 5th, 2009 at 11:01 PM
Get hold of a Grainger catalog. Find the sheave (pulley) you want and then find the correct insert for it that has the right ID for the motor shaft. At least around here, the local store guys are pretty good about helping you out. This applies to V-belts and cog-type belts anyhow. Not too sure about flat belts, since I never use anything like that.
To be perfectly honest, I think your fears of bench grinders are overblown, but belt grinders do have some advantages. I don’t know if I’d go to all the trouble of building one, though.
My $0.02, YMMV.
February 5th, 2009 at 11:03 PM
Already checked Grainger.
February 6th, 2009 at 2:52 AM
How about MSC or MC?
February 6th, 2009 at 6:32 AM
Another place to try would be McMaster-Carr, http://www.mcmaster.com. They’ve got all kinds of weird machinery and hardware.
Not cheap. But they’ve solved problems for me in the past. And the don’t have a minimum order, unlike similar joints.
February 6th, 2009 at 7:34 AM
I liked your idea of getting a piece of junk belt sander and cannibalizing it for the rollers. Heck, I got a good one on Craigslist for about $40. I’m sure you can mount the attached fine adjustment without too much trouble. If the shaft hole is too small for your
motor, you can buy a drill press or milling machine…
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I guess I shouldn’t play like that.
February 6th, 2009 at 12:24 PM
I’m doing some conveyor work and was wondering about you using something from these guys:
http://conveyor-parts.com/
There is a 10″ wide version for cheep in the web table and they make custom widths also:
http://conveyor-parts.com/index.cfm?mf=browse.showPart&partClassID=5010&PName=Light%20Duty%20Rollers
February 6th, 2009 at 12:34 PM
I assume you’ve seen this site:
http://www.metalwebnews.com/howto/sander1/sander.html
Check out the drive and Idler wheels here:
http://www.beaumontmetalworks.com/
February 6th, 2009 at 12:39 PM
That sander link is hilarious. Git ‘r done! I guess I was right about metal being overkill for a homemade machine. But since I got the idea from someone who has built several grinders, I don’t see how I could have been wrong.
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Notice how the man says the wheels are the hardest thing to come up with. No wonder he can sell them for $82 each.