Posted: 7/17/2014 9:34:58 AM EDT
| Looking to get a rough idea on cost. Pulley relies on a friction/tension fit on a shaft. If I send you the piece with the shaft and the pulley can you figure out the math for relying on a tension fit? Just as a rough guess, center hole needs bored from 5/8 to 3/4. Metal pulley. |
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How much power and torque will it be carrying? Is the pulley hub large enough in diameter to bore out? Set screw? A correct size pulley may be cheaper. No set screw, all friction/press on/off fit. Pulley hub looks fine to bore to from .685 to .75. There is not an off the shelf pulley with the bore size, and groove number I need. So my best choice is factory speced pulley bored out to new shaft size. Looked into a few guys who custom make pulleys, but they are billet and $200+. I figured for $25 or $50 I could get someone to bore it out so I can see if my idea will even work. |
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No set screw, all friction/press on/off fit. Pulley hub looks fine to bore to from .685 to .75. There is not an off the shelf pulley with the bore size, and groove number I need. So my best choice is factory speced pulley bored out to new shaft size. Looked into a few guys who custom make pulleys, but they are billet and $200+. I figured for $25 or $50 I could get someone to bore it out so I can see if my idea will even work. Quoted:
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How much power and torque will it be carrying? Is the pulley hub large enough in diameter to bore out? Set screw? A correct size pulley may be cheaper. No set screw, all friction/press on/off fit. Pulley hub looks fine to bore to from .685 to .75. There is not an off the shelf pulley with the bore size, and groove number I need. So my best choice is factory speced pulley bored out to new shaft size. Looked into a few guys who custom make pulleys, but they are billet and $200+. I figured for $25 or $50 I could get someone to bore it out so I can see if my idea will even work. Overbore and use a wedge shaft clamp. MAYBE if you can give a machine shop the pulley and shaft, but otherwise 'friction' fit is not going to happen. It is actually an 'interference' fit and needs a very fine finish on the shaft and bore. The pulley usually needs to be a lot better than zinc (AKA 'pot metal'). Think steel, Al, or cast iron to get a good enough finish. |
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Overbore and use a wedge shaft clamp. MAYBE if you can give a machine shop the pulley and shaft, but otherwise 'friction' fit is not going to happen. It is actually an 'interference' fit and needs a very fine finish on the shaft and bore. The pulley usually needs to be a lot better than zinc (AKA 'pot metal'). Think steel, Al, or cast iron to get a good enough finish. Quoted:
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How much power and torque will it be carrying? Is the pulley hub large enough in diameter to bore out? Set screw? A correct size pulley may be cheaper. No set screw, all friction/press on/off fit. Pulley hub looks fine to bore to from .685 to .75. There is not an off the shelf pulley with the bore size, and groove number I need. So my best choice is factory speced pulley bored out to new shaft size. Looked into a few guys who custom make pulleys, but they are billet and $200+. I figured for $25 or $50 I could get someone to bore it out so I can see if my idea will even work. Overbore and use a wedge shaft clamp. MAYBE if you can give a machine shop the pulley and shaft, but otherwise 'friction' fit is not going to happen. It is actually an 'interference' fit and needs a very fine finish on the shaft and bore. The pulley usually needs to be a lot better than zinc (AKA 'pot metal'). Think steel, Al, or cast iron to get a good enough finish. So provided I shipped them the pump and pulley and said I wanted this pulley to fit on this shaft in a interference fit, they could so it for me? I know pulley ID/bore is .685, and shaft is right about 0.75. I figure I could get them to bore pulley to 0.74 and it would be tight enough, or should I go smaller? |
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Any reason you can't use something like a Gates QD or Taper-Lok bushing? Pulley is press fit only. I doubt I will get lucky enough to find one for my application. My alternative is if the pulley cannot be bored out for whatever reason, is to have the shaft lathed down from 0.748 to 0.685 (or there about). This entails removing the shaft from its assembly which I would rather not too. I have a drill press, but after using a lathe I'd rather not ghetto rig this. |
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So provided I shipped them the pump and pulley and said I wanted this pulley to fit on this shaft in a interference fit, they could so it for me? I know pulley ID/bore is .685, and shaft is right about 0.75. I figure I could get them to bore pulley to 0.74 and it would be tight enough, or should I go smaller? Quoted:
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How much power and torque will it be carrying? Is the pulley hub large enough in diameter to bore out? Set screw? A correct size pulley may be cheaper. No set screw, all friction/press on/off fit. Pulley hub looks fine to bore to from .685 to .75. There is not an off the shelf pulley with the bore size, and groove number I need. So my best choice is factory speced pulley bored out to new shaft size. Looked into a few guys who custom make pulleys, but they are billet and $200+. I figured for $25 or $50 I could get someone to bore it out so I can see if my idea will even work. Overbore and use a wedge shaft clamp. MAYBE if you can give a machine shop the pulley and shaft, but otherwise 'friction' fit is not going to happen. It is actually an 'interference' fit and needs a very fine finish on the shaft and bore. The pulley usually needs to be a lot better than zinc (AKA 'pot metal'). Think steel, Al, or cast iron to get a good enough finish. So provided I shipped them the pump and pulley and said I wanted this pulley to fit on this shaft in a interference fit, they could so it for me? I know pulley ID/bore is .685, and shaft is right about 0.75. I figure I could get them to bore pulley to 0.74 and it would be tight enough, or should I go smaller? Fits are standardized by ANSI. I believe what you are looking for is called a force fit. This page can help you out a bit. According to this, you should be looking at about a 0.7484 ID on your pulley. 0.74 will be way too tight. |
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Fits are standardized by ANSI. I believe what you are looking for is called a force fit. This page can help you out a bit. According to this, you should be looking at about a 0.7484 ID on your pulley. 0.74 will be way too tight. Quoted:
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How much power and torque will it be carrying? Is the pulley hub large enough in diameter to bore out? Set screw? A correct size pulley may be cheaper. No set screw, all friction/press on/off fit. Pulley hub looks fine to bore to from .685 to .75. There is not an off the shelf pulley with the bore size, and groove number I need. So my best choice is factory speced pulley bored out to new shaft size. Looked into a few guys who custom make pulleys, but they are billet and $200+. I figured for $25 or $50 I could get someone to bore it out so I can see if my idea will even work. Overbore and use a wedge shaft clamp. MAYBE if you can give a machine shop the pulley and shaft, but otherwise 'friction' fit is not going to happen. It is actually an 'interference' fit and needs a very fine finish on the shaft and bore. The pulley usually needs to be a lot better than zinc (AKA 'pot metal'). Think steel, Al, or cast iron to get a good enough finish. So provided I shipped them the pump and pulley and said I wanted this pulley to fit on this shaft in a interference fit, they could so it for me? I know pulley ID/bore is .685, and shaft is right about 0.75. I figure I could get them to bore pulley to 0.74 and it would be tight enough, or should I go smaller? Fits are standardized by ANSI. I believe what you are looking for is called a force fit. This page can help you out a bit. According to this, you should be looking at about a 0.7484 ID on your pulley. 0.74 will be way too tight. Sweet appreciate it. So if anyone here wants to take me up on this offer, I'll get a pulley and pump coming and see if you can do it for me and make some coin! 
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Really just depends. Size of pulley, shape, material, tolerance all matter. If there is a good way to chuck it up, and it fits on the lathe, shouldn't be too big of a deal. Nobody wants to chance ruining your parts or taking the time to ship it.
If the pulley was less than 6" diameter, I could give it a shot, but you would be running the risk of me trashing it and it costing even more than purchasing it... Drill is a quick way to cut a rough hole of 'about' a certain size. A reamer cleans up a drilled hole, but won't really make its own hole. The reamer can make a oretty round hole to less than .001, the drill will make a sort-of roundish hole to within .002-.003" of desired dimension. The finish will be better with the reamer. If you get really close with a drill you can use sandpaper taped to a rod chucked in a drill to sneak up on it... |
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Really just depends. Size of pulley, shape, material, tolerance all matter. If there is a good way to chuck it up, and it fits on the lathe, shouldn't be too big of a deal. Nobody wants to chance ruining your parts or taking the time to ship it. If the pulley was less than 6" diameter, I could give it a shot, but you would be running the risk of me trashing it and it costing even more than purchasing it... Drill is a quick way to cut a rough hole of 'about' a certain size. A reamer cleans up a drilled hole, but won't really make its own hole. The reamer can make a oretty round hole to less than .001, the drill will make a sort-of roundish hole to within .002-.003" of desired dimension. The finish will be better with the reamer. If you get really close with a drill you can use sandpaper taped to a rod chucked in a drill to sneak up on it... So I should bore it out to 19mm with the bit, and then hit it with the reamer? The pulley is less than 6. Actually will have 2 pulleys on hand and a 19mm bit and reamer to play with. I need within 2 thous tolerance since factory speced pulley bore for what I am trying to do is .748, and the shaft is .75. I figure a .2 thous interference fit is good. Once I figure out what the pulley looks like when I get it bored out. I'll decide if I want to run it or figure out something else involving over bore or taper locks. |
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That's pretty much it. Try to keep the speed down on whatever you are drilling with, 3/4" bit in metal needs to be going just a few hundred rpm. Some cutting oil would be smart too. If it doesn't cost much to try, go ahead.
If you want, I may be able to do it... if I don't ruin it I will charge you. 
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Finally figured out what I needed to do. Is a drill bit or a reamer better? Or what is the deciding factor on when to use a reamer/when to use a drill bit? Drilled holes ALWAYS end up a few thousandths larger. Drill undersize for finished hole and use a hand reamer. Note that a larger 'hand' reamer often still requires a lath to use. You just do not use it under power unless you engage a lot of back screws for a very fine pitch thread. A lot of oil. Even grease. Plenty of backing out and chip cleaning and fresh lube. A pressurized oil delivery system is a real plus, but you may get away with a good setup if you understand you are likely to wreck the reamer. On a lath an inside boring bar and a 0.0001 compound feed setup (84 degrees) makes a 0.001 compound feed a 0.0001 cutter feed. |