Joe Michaels
Diamond
- Joined
- Apr 3, 2004
- Location
- Shandaken, NY, USA
Live24wheel:
Thanks for the compliment. Lathe chucks are like anything else, and "you gets what you pays for". I can't comment yea or nay on the quality of the "Import" (Chinese or Indian) chucks. The prices certainly are low enough, but there have been some posts about people finding jaws not square to the spindle or excessive runout when the jaws were clamped on a piece of drill rod or similar. Other people have had no issues with their "Import" chucks.
Looking at this from the perspective of price:
-if you buy a used US, English, or European made chuck online (read: ebay), you are buying something sight unseen and have no way of knowing whether it is in as good a condition as the seller represents it as being. Remember the saying for buyers of used goods: "Caveat Emptor"- let the buyer beware. Or, let the buyer hold no illusions as to the condition of a used chuck.
-If you buy an import chuck and discover the jaws are out of square or have excessive runout, you have two recourses: chase the seller- if they will make good. Making good may be sending you another chuck, which may be as bad or worse than the one you already received. Or, it may be better. The seller does not do any inspections or checks on the imported tooling and half the time has no more idea about how it is checked or used than the man in the moon.
-If you buy a used US, British, or European made chuck, you again are taking a chance as to whether the jaws are still square with the centerline of the spindle, and whether the jaws hold work reasonably true. Remember: a 3 jaw "universal" or "scroll" chuck can NEVER be counted upon to hold work dead true. With a used 3 jaw chuck you are lucky if it holds work within 0.003-0.005" total indicated runout over the range of sizes the chuck can hold- and this has to happen on a good day with the moon in the right house.
-This brings things to the common factor: making a sloppy 3 jaw chuck better on your own. This consists of grinding the jaws in place with the chuck on the spindle of your lathe. It takes a toolpost grinder with an extended spindle for internal grinding, and some sort of ring for the chuck jaws to close against as they need to have all the backlash taken up, and a preload applied. Whether you purchase a used "name" chuck like a Buck, Bison, Pratt, or older Cushman, or whether you purchase a new chuck from Asia and find this sort of problem, the fix is the same.
-Bear in mind that three jaw chucks, even when fitted with an adjustable back plate (such as the "Set Tru" system), will only hold work of one specific size so that it runs true. Move the jaws to chuck another size of work, and that chuck may hold the work so it runs not quite so true.
The market seems to be flooded- at least on ebay and the internet, along with MSC and Enco and Travers- with cheap imported lathe chucks. You can buy a 3 jaw 10" Asian-made lathe chuck for maybe 250 bucks, backplate included. Price that same chuck from Bison (Polish) and you might be bumping 1000 bucks. Find a Buck chuck of that same size/type and you might be up over 1500 dollars.
Your lathe came with two chucks. The 3 jaw chuck is a Buck chuck, and is likely nowhere near as old as the lathe. It appears to have one-piece jaws, so hopefully, you have the set of reverse jaws with it as well. My advice is to live with the Buck chuck unless the jaws are horribly loose in the body of the chuck. Backlash in the scroll is expectable as a chuck is used and wear occurs. I'd chuck a test bar in the 3 jaw chuck and see how bad it really is. I use a piece of heavier diameter drill rod or turned-ground-and polished round stock. I keep a piece of
1 1/4" diameter "Stressproof" (1141 steel, specially forged for minimizing distortion after machining) with centers in each end as a test bar. Nothing fancy. Get something similar and chuck it in the Buck 3 jaw chuck. Put a dial indicator in the toolpost and bring it to bear against the "test bar" by cranking in the cross slide or compound. Start with the indicator as close to the chuck jaws as possible. Mark the starting point (about 9:00 as you face the chuck body and "look into the spindle") on the chuck- Sharpie, soapstone, paint marker- anything to give you a starting point. Lock the carriage to the bed ways. Put the speed selector levers on the headstock "between gears" so the spindle turns freely. Put some preload on the indicator and zero the dial indicator. Roll the spindle thru 360 degrees and see how much runout is present.
Note it, and make a sketch as to where it is at its worst (referencing jaw numbers).
Move the carriage out a few inches from the chuck and repeat the exercise, seeing whether the runout repeats or gets worse.
I would shy from simply traversing the test bar with the indicator in the carriage as you have an old lathe with some bed wear. The indicator may not read as though the bedways are dead parallel to the spindle. And, the lathe is not levelled at this point- not that it is that critical. Simple runout checks at a few locations getting further from the chuck will tell you what you need to know.
Runout that is consistent (or nearly so) along the test bar shows what is expectable in a used 3 jaw chuck. Runout that worsens as the indicator is moved further from the chuck means the chuck jaws are worn and not closing squarely. Sometimes older chucks get "bellmouthed"- where the tips of the jaws are actually wider than the lower portions of the jaws down near the tee slots in the chuck body. I've seen older/worn 3 jaw chucks where I could see a hint of daylight between the jaws and a ground test bar in the neighborhood of the tips of the jaws, while things closed tight and gripped the bar down near the tee slots in the chuck body.
A check of your chuck may tell you a lot, and then we come back to "the devil you know is better than the devil you don't know". I.E.- a used chuck off ebay or similar is an unknown, as are the cheap Asian import chucks. If you can regrind the jaws on the Buck chuck, you are ahead of the game. Or, contact Worldwide Chuck Service in Kalamazoo, MI. This is a firm that specializes in lathe chucks- selling new ones, repairing used ones for customers. It is a firm run by people who'd worked for Buck-Forkardt, and they know their business. Not cheap, but able to recondition and repair lathe chucks and restore accuracy.
Thanks for the compliment. Lathe chucks are like anything else, and "you gets what you pays for". I can't comment yea or nay on the quality of the "Import" (Chinese or Indian) chucks. The prices certainly are low enough, but there have been some posts about people finding jaws not square to the spindle or excessive runout when the jaws were clamped on a piece of drill rod or similar. Other people have had no issues with their "Import" chucks.
Looking at this from the perspective of price:
-if you buy a used US, English, or European made chuck online (read: ebay), you are buying something sight unseen and have no way of knowing whether it is in as good a condition as the seller represents it as being. Remember the saying for buyers of used goods: "Caveat Emptor"- let the buyer beware. Or, let the buyer hold no illusions as to the condition of a used chuck.
-If you buy an import chuck and discover the jaws are out of square or have excessive runout, you have two recourses: chase the seller- if they will make good. Making good may be sending you another chuck, which may be as bad or worse than the one you already received. Or, it may be better. The seller does not do any inspections or checks on the imported tooling and half the time has no more idea about how it is checked or used than the man in the moon.
-If you buy a used US, British, or European made chuck, you again are taking a chance as to whether the jaws are still square with the centerline of the spindle, and whether the jaws hold work reasonably true. Remember: a 3 jaw "universal" or "scroll" chuck can NEVER be counted upon to hold work dead true. With a used 3 jaw chuck you are lucky if it holds work within 0.003-0.005" total indicated runout over the range of sizes the chuck can hold- and this has to happen on a good day with the moon in the right house.
-This brings things to the common factor: making a sloppy 3 jaw chuck better on your own. This consists of grinding the jaws in place with the chuck on the spindle of your lathe. It takes a toolpost grinder with an extended spindle for internal grinding, and some sort of ring for the chuck jaws to close against as they need to have all the backlash taken up, and a preload applied. Whether you purchase a used "name" chuck like a Buck, Bison, Pratt, or older Cushman, or whether you purchase a new chuck from Asia and find this sort of problem, the fix is the same.
-Bear in mind that three jaw chucks, even when fitted with an adjustable back plate (such as the "Set Tru" system), will only hold work of one specific size so that it runs true. Move the jaws to chuck another size of work, and that chuck may hold the work so it runs not quite so true.
The market seems to be flooded- at least on ebay and the internet, along with MSC and Enco and Travers- with cheap imported lathe chucks. You can buy a 3 jaw 10" Asian-made lathe chuck for maybe 250 bucks, backplate included. Price that same chuck from Bison (Polish) and you might be bumping 1000 bucks. Find a Buck chuck of that same size/type and you might be up over 1500 dollars.
Your lathe came with two chucks. The 3 jaw chuck is a Buck chuck, and is likely nowhere near as old as the lathe. It appears to have one-piece jaws, so hopefully, you have the set of reverse jaws with it as well. My advice is to live with the Buck chuck unless the jaws are horribly loose in the body of the chuck. Backlash in the scroll is expectable as a chuck is used and wear occurs. I'd chuck a test bar in the 3 jaw chuck and see how bad it really is. I use a piece of heavier diameter drill rod or turned-ground-and polished round stock. I keep a piece of
1 1/4" diameter "Stressproof" (1141 steel, specially forged for minimizing distortion after machining) with centers in each end as a test bar. Nothing fancy. Get something similar and chuck it in the Buck 3 jaw chuck. Put a dial indicator in the toolpost and bring it to bear against the "test bar" by cranking in the cross slide or compound. Start with the indicator as close to the chuck jaws as possible. Mark the starting point (about 9:00 as you face the chuck body and "look into the spindle") on the chuck- Sharpie, soapstone, paint marker- anything to give you a starting point. Lock the carriage to the bed ways. Put the speed selector levers on the headstock "between gears" so the spindle turns freely. Put some preload on the indicator and zero the dial indicator. Roll the spindle thru 360 degrees and see how much runout is present.
Note it, and make a sketch as to where it is at its worst (referencing jaw numbers).
Move the carriage out a few inches from the chuck and repeat the exercise, seeing whether the runout repeats or gets worse.
I would shy from simply traversing the test bar with the indicator in the carriage as you have an old lathe with some bed wear. The indicator may not read as though the bedways are dead parallel to the spindle. And, the lathe is not levelled at this point- not that it is that critical. Simple runout checks at a few locations getting further from the chuck will tell you what you need to know.
Runout that is consistent (or nearly so) along the test bar shows what is expectable in a used 3 jaw chuck. Runout that worsens as the indicator is moved further from the chuck means the chuck jaws are worn and not closing squarely. Sometimes older chucks get "bellmouthed"- where the tips of the jaws are actually wider than the lower portions of the jaws down near the tee slots in the chuck body. I've seen older/worn 3 jaw chucks where I could see a hint of daylight between the jaws and a ground test bar in the neighborhood of the tips of the jaws, while things closed tight and gripped the bar down near the tee slots in the chuck body.
A check of your chuck may tell you a lot, and then we come back to "the devil you know is better than the devil you don't know". I.E.- a used chuck off ebay or similar is an unknown, as are the cheap Asian import chucks. If you can regrind the jaws on the Buck chuck, you are ahead of the game. Or, contact Worldwide Chuck Service in Kalamazoo, MI. This is a firm that specializes in lathe chucks- selling new ones, repairing used ones for customers. It is a firm run by people who'd worked for Buck-Forkardt, and they know their business. Not cheap, but able to recondition and repair lathe chucks and restore accuracy.