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- Jul 11, 2003
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- 3,258
Drill Chucks and Tapers
I see so many posts about folks not satisfied with their drill press chucks and drilling setups. The most-common problems are that the chuck has way too much run-out (wobble) and the chuck won't stay on! Now, I could ramble on an on about this subject, but I'll try to keep it simple.
There are two problems the Asian machine manufacturers leave the end-user to solve. First of all, the chucks they use are horribly-cheap. They are so poorly-made. Shoddy materials, inconsistent tolerances, and lousy workmanship account for the bad quality of these chucks. Individually, the parts that comprise one of these drill chucks are probably okay, but add them together to make an assembly, and the assembly is a train wreck.
This problem is simply corrected by purchasing a new chuck. In many of the catalogs you can buy a brand-new, keyless chuck for under $50. Ironically, most of these are Asian-made as well, but their precision is fairly good. Definitely good enough to bore a straight hole in the type of work we do! There is one chuck available at MSC right now, made by Rohm (European-made... nice!), with 1-4" max opening fr only 48 bucks. How can you go wrong with that? You don't need to break open the piggy bank or pull out that wad of bills you got stuffed into the mattress to get some decent quality and precision into your work.
When ordering your new chuck, be sure to match the chuck taper your machine uses. This should be printed on the chuck you are replacing, and the number will have the letters "JT" in it. This stands for "Jacobs Taper" and is the standard used in North American and many European machinery. A 33JT chuck is typically the one you need for these. There are also a few other tapers out there, and even some screw-on types, so be sure of what you have so you don't buy the wrong chuck.
The second problem associated with the Asian (and some domestic) drill presses is that the chuck won't stay "glued" to the taper.
EDIT: Crap! I accidentally hit send when replying to an email from my boss. I'll proceed.
So your drill chuck keeps popping out as you are drill a knife blank or what have you. Its irritating to say the least, right? There are several reasons for this, and I won't elaborate and bore you, but instead try to make some common-sense fixes to the problem.
CLEAN CLEAN CLEAN! The tapers must be clean and burr-free. There shouldn't be any grease, dirt or oils on the taper, or the chuck when you install it. Asian countries are so hot and humid, they liberally apply grease and waxy corriosion preventives to everything. Incidentally, this is why I recommend a complete teardown and reassembly of every Asian-made machine purchased.
The whole idea behind a taper is to allow the chuck and the press spindle to "marry" becoming one unit with solid mass, spinning with a high degree of concentricity. In other words, its held in there with friction, and the taper helps keep it all spinning solidly together around the same axis. If you add oil or if there are burrs and dirt in there, its not going to seat properly and fall out when you least expect it - usually during something important, if Mr. Murphy has anything to do with it.
Clean and check the spindle for burrs. If a burr is present on the spindle, you will need to clena that off. I recommend rubbing it off gently with some 400 grit paper, backed with something hard. Don't try to round the spindle by sanding all around it - just do that one spot. It'll be somewhat flat, but the you won't reshape the overall geometry of the taper this way. Now start the press and buff the taper lightly with some medium non-woven abrasive pad. This should set it up nice and clean. Not too much! We don't want to polish it. The finish on the taper is part of why it grabs and holds onto the chuck.
Now look inside the chuck itself. Is it clean? Burrs or grit? Clean that out of necessary. I like to use acetone on a rag, or even some windex in a pinch. Now we need to install the chuck to the taper.
DON'T HAMMER IT ON! That's the best way to get it on crooked or damage the spindle, bearings, chuck jaws, or all three. The best way is to close the chuck down on a steel rod and tighten it. Be sure to bottom the end of the rod up into the chuck so it don't go any farther up inside. You want about an inch protruding from the jaws.
Now install the chuck onto the spindle and using the handle, lower the chuck down onto block of wood on your table. This should be sufficient to seat the chuck onto the spindle. If you still feel insecure, tap the steel rod - still chucked-up - with a small brass or nylon hammer. That should do it!
Now you get to have fun making lots of holes without the worry of your chuck falling off in your lap.
I see so many posts about folks not satisfied with their drill press chucks and drilling setups. The most-common problems are that the chuck has way too much run-out (wobble) and the chuck won't stay on! Now, I could ramble on an on about this subject, but I'll try to keep it simple.
There are two problems the Asian machine manufacturers leave the end-user to solve. First of all, the chucks they use are horribly-cheap. They are so poorly-made. Shoddy materials, inconsistent tolerances, and lousy workmanship account for the bad quality of these chucks. Individually, the parts that comprise one of these drill chucks are probably okay, but add them together to make an assembly, and the assembly is a train wreck.
This problem is simply corrected by purchasing a new chuck. In many of the catalogs you can buy a brand-new, keyless chuck for under $50. Ironically, most of these are Asian-made as well, but their precision is fairly good. Definitely good enough to bore a straight hole in the type of work we do! There is one chuck available at MSC right now, made by Rohm (European-made... nice!), with 1-4" max opening fr only 48 bucks. How can you go wrong with that? You don't need to break open the piggy bank or pull out that wad of bills you got stuffed into the mattress to get some decent quality and precision into your work.
When ordering your new chuck, be sure to match the chuck taper your machine uses. This should be printed on the chuck you are replacing, and the number will have the letters "JT" in it. This stands for "Jacobs Taper" and is the standard used in North American and many European machinery. A 33JT chuck is typically the one you need for these. There are also a few other tapers out there, and even some screw-on types, so be sure of what you have so you don't buy the wrong chuck.
The second problem associated with the Asian (and some domestic) drill presses is that the chuck won't stay "glued" to the taper.
EDIT: Crap! I accidentally hit send when replying to an email from my boss. I'll proceed.
So your drill chuck keeps popping out as you are drill a knife blank or what have you. Its irritating to say the least, right? There are several reasons for this, and I won't elaborate and bore you, but instead try to make some common-sense fixes to the problem.
CLEAN CLEAN CLEAN! The tapers must be clean and burr-free. There shouldn't be any grease, dirt or oils on the taper, or the chuck when you install it. Asian countries are so hot and humid, they liberally apply grease and waxy corriosion preventives to everything. Incidentally, this is why I recommend a complete teardown and reassembly of every Asian-made machine purchased.
The whole idea behind a taper is to allow the chuck and the press spindle to "marry" becoming one unit with solid mass, spinning with a high degree of concentricity. In other words, its held in there with friction, and the taper helps keep it all spinning solidly together around the same axis. If you add oil or if there are burrs and dirt in there, its not going to seat properly and fall out when you least expect it - usually during something important, if Mr. Murphy has anything to do with it.
Clean and check the spindle for burrs. If a burr is present on the spindle, you will need to clena that off. I recommend rubbing it off gently with some 400 grit paper, backed with something hard. Don't try to round the spindle by sanding all around it - just do that one spot. It'll be somewhat flat, but the you won't reshape the overall geometry of the taper this way. Now start the press and buff the taper lightly with some medium non-woven abrasive pad. This should set it up nice and clean. Not too much! We don't want to polish it. The finish on the taper is part of why it grabs and holds onto the chuck.
Now look inside the chuck itself. Is it clean? Burrs or grit? Clean that out of necessary. I like to use acetone on a rag, or even some windex in a pinch. Now we need to install the chuck to the taper.
DON'T HAMMER IT ON! That's the best way to get it on crooked or damage the spindle, bearings, chuck jaws, or all three. The best way is to close the chuck down on a steel rod and tighten it. Be sure to bottom the end of the rod up into the chuck so it don't go any farther up inside. You want about an inch protruding from the jaws.
Now install the chuck onto the spindle and using the handle, lower the chuck down onto block of wood on your table. This should be sufficient to seat the chuck onto the spindle. If you still feel insecure, tap the steel rod - still chucked-up - with a small brass or nylon hammer. That should do it!
Now you get to have fun making lots of holes without the worry of your chuck falling off in your lap.
