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Drill chuck

#1
So what is the correct way to measure a drill chuck taper?
I have an older PA drill press and can find nothing in the manual about what size taper it has.
I hate keyed chucks and would love to change to keyless but the measurements I have taken don't appear to match with anything.
Skinny end and fat end? Is it that simple?
 

Everett

Active Member
#4
Are you referring to the taper going into the quill socket (drill press side) or going into the back of the chuck (chuck side)? Reason I ask is that often the drill chucks go onto an arbor that has a Morse taper on the drill side and a Jacobs taper on the chuck side. Last chuck I bought for the lathe required that I get an arbor as well at the same time.
 

Bofobo

Well-Known Member
#5
The arbour may be integral, with the chuck being the only removable piece, if so its likely a jacobs taper and some wedge blocks will make quick work of that. Mrpete222 has some videos on some of his tiny drill presses and changing the chucks
 
#6
The chuck taper should be marked on the chuck some where.

What size press is it? Current 8" - 16" PA presses and press chucks state B16.
 
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#7
Thanks for the input everyone. This is for the female end of the chuck. YYCHobbyMachinist was right, it's marked J3 right on the chuck.
I had no idea these things were that expensive:(. I don't think I paid that much for the whole machine 15 years ago.
I can put up with my keyed chuck for a while yet.
I don't need that kind of precision for the putzing around I do.
 
#8
Thanks for the input everyone. This is for the female end of the chuck. YYCHobbyMachinist was right, it's marked J3 right on the chuck.
I had no idea these things were that expensive:(. I don't think I paid that much for the whole machine 15 years ago.
I can put up with my keyed chuck for a while yet.
I don't need that kind of precision for the putzing around I do.
I got some really good deals on banggood.com. Most of it has been decent quality, some really good, some crap. The keyless drill chucks and arbors have been excellent
 

Dabbler

Well-Known Member
#10
I recently got some keyless chucks at KBC - that can't hold a drill worth anything. I've used my Jacobs' keyed chucks for 40 years, and they still hold like new. Now I have tow boat anchors as well.

You really are better off.
 
#11
I recently got some keyless chucks at KBC - that can't hold a drill worth anything. I've used my Jacobs' keyed chucks for 40 years, and they still hold like new. Now I have tow boat anchors as well.

You really are better off.
I pressed buy on one from Banggood yesterday so I guess I'll find out in a few weeks. The chuck on my drill press has always been glitchy but I wasn't too concerned about it. It has gotten real sticky lately and tends to bind when loosening the chuck.
 
#12
So the Banggood keyless chuck came today, complete with a morse to jacobs adapter, which I don't need.
While it's pretty and has a smooth action, I'm both not impressed and confused.
Not impressed because of the runout. I figured I would compare the 2 chucks just for fun. The old keyed chuck had a .002 runout. I was measuring on the shank of a 1/2 inch drill bit. The keyless chuck had a runout of .013 on the same drill bit. I changed them back and forth a few times and no change. While I mostly don't do anything requiring much accuracy, I'm still disappointed.
I'm confused because of the action of the jaws. On the keyless chucks I have, when you you turn the chuck to either tighten or loosen the jaws, they simply extend or retract, as you would expect, but they do not turn with the chuck.
On the new one, when you turn the collar, the jaws turn with it. Some of my bits have three flat sides to hold better in the chuck and with the jaws rotating it is a bitch to get them lined up. On a round shank it doesn't matter but with these it's a real pain.
Live and learn I guess.
 
#13
So the Banggood keyless chuck came today, complete with a morse to jacobs adapter, which I don't need.
While it's pretty and has a smooth action, I'm both not impressed and confused.
Not impressed because of the runout. I figured I would compare the 2 chucks just for fun. The old keyed chuck had a .002 runout. I was measuring on the shank of a 1/2 inch drill bit. The keyless chuck had a runout of .013 on the same drill bit. I changed them back and forth a few times and no change. While I mostly don't do anything requiring much accuracy, I'm still disappointed.
I'm confused because of the action of the jaws. On the keyless chucks I have, when you you turn the chuck to either tighten or loosen the jaws, they simply extend or retract, as you would expect, but they do not turn with the chuck.
On the new one, when you turn the collar, the jaws turn with it. Some of my bits have three flat sides to hold better in the chuck and with the jaws rotating it is a bitch to get them lined up. On a round shank it doesn't matter but with these it's a real pain.
Live and learn I guess.
That is truly unfortunate, I guess I got really lucky, mine has less than 0.001 runout and is smooth as silk and very nicley ground. I was very impressed when I got it. I guess its a bit of the luck of the draw type thing.
What arbor did you get? I've been looking for a MT3-JT6 and haven't been able to find one yet ( I have to admit I haven't scoured the inter web tho)
 
#14
That is truly unfortunate, I guess I got really lucky, mine has less than 0.001 runout and is smooth as silk and very nicley ground. I was very impressed when I got it. I guess its a bit of the luck of the draw type thing.
What arbor did you get? I've been looking for a MT3-JT6 and haven't been able to find one yet ( I have to admit I haven't scoured the inter web tho)
MT2-JT3
Do the jaws on yours rotate with the collar when you tighten or loosen?
 
#15
Just went and checked, no they don't. (It's the B16-1/2" to MT2)
I also checked the JT6 that I'm looking for an arbor for and they do. Maybe the different types? I'm not sure what the difference is between B16 and JT6 they are identical in appearance but the JT6 jaws rotate with the collar. Things that make you go hmmmm.
 

PeterT

Ultra Member
Premium Member
#16
That's a lot of runout. For sure a small drill size breaker. Just to confirm, are you putting the drill chucks on the same arbor body located in the drill press? Or is it old chuck + old arbor vs new chuck + new arbor. Reason I ask is maybe you have a good chuck & bad arbor. If so, put the arbor only in the drill press & measure runout on the taper body with a DTI. If that is out .012 and your chuck is out .001 that's a completely different situation. Dont throw the baby out with the bath water.

I wouldn't worry about the jaw mechanism, they can work on different principles. The point is how concentric are they & how reliable they grip. So when you close them & look at the end, how do the jaws match up? Nicely or Eesh? I would also try a smaller size test shaft say .375 or .250 to see if you get same TIR on all shafts. Some chucks grip a bit worse at extremities of range but it shouldn't be much. BTW, drills are not really the best thing for measuring runout like this, at least in an absolute sense. Its better to have some kind of ground pin or even drill rod. Its a good thing to have kicking around it will get a lot of use in the shop.
 
#17
That's a lot of runout. For sure a small drill size breaker. Just to confirm, are you putting the drill chucks on the same arbor body located in the drill press? Or is it old chuck + old arbor vs new chuck + new arbor. Reason I ask is maybe you have a good chuck & bad arbor. If so, put the arbor only in the drill press & measure runout on the taper body with a DTI. If that is out .012 and your chuck is out .001 that's a completely different situation. Dont throw the baby out with the bath water.

I wouldn't worry about the jaw mechanism, they can work on different principles. The point is how concentric are they & how reliable they grip. So when you close them & look at the end, how do the jaws match up? Nicely or Eesh? I would also try a smaller size test shaft say .375 or .250 to see if you get same TIR on all shafts. Some chucks grip a bit worse at extremities of range but it shouldn't be much. BTW, drills are not really the best thing for measuring runout like this, at least in an absolute sense. Its better to have some kind of ground pin or even drill rod. Its a good thing to have kicking around it will get a lot of use in the shop.
I measured both chucks on the original arbour. I don't have a DTI. I used a dial indicator on a mag base. I measured as close to the chuck as I could on the smooth part of the drill bit. I wasn't worried about the amount of runout really, just wanted to do a comparison. I'll swap arbours out tomorrow and try again.
The jaws on the new chuck close up perfectly, I think, and look like they could grip a sewing needle.
It's quite pretty:), but at least 1 1/2 inches longer. That won't matter though for what I do.
 

PeterT

Ultra Member
Premium Member
#18
And you are positive the male taper of the arbor is the spec match of the socket on the chuck? Are there any inscriptions on the chuck to validate? Wouldn't be the first time they sent the wrong model number. And ditto for the arbor going into quill? If it was close (but not right) it might appear to stick in position but its not really mated.

If you tug on the chuck lightly from one side can you make the runout stay in one position? Worded another way If you felt pen the max runout position, is it always in the same spot by removing & resetting?

I would blue one face of each arbor surface, stick it together, remove & observe. If its all smeared equally its a decent fit. If you see a ring or some suspicious pattern, something is up.

Do you feel any burs on the inside of jaws?

Another test, kind of iffy but here goes. Since you know the low runout of your old chuck, set it up in the spindle as normal. Chuck up a shot section of something accurate like a dowel pin. Now tighten your new chuck onto that pin upside down. Can you measure different runout on the socket underside? (oh wait you said no dial test indicator, just an indicator? Try & poke the plunger up at an angle using the mag stand).