JT 2-1/2 Spindle Chuch replacement

I've got a (roughly) 35 year old AMT (American Machine Tool) bench drill
press that's still working wonderfully and although I've thought
occasionally of replacing it with a more modern DP with conveniences like a
larger table, a ratchet drive on the table and possibly even variable speed,
I still can't bring myself to part with this marvelous piece of machinery.
BUT ... I'd like to purchase a better chuck. Some of the drilling I do with
this beast is in the #70-80 range in both model working and PC board
manufacture and while I don't yet have the tool to measure the runout (it's
been ordered), I think that I need something with a little better precision,
even if a smaller range.
HOWEVER ... I don't think I've ever seen any product offered in the last 30
years for a JT#2-1/2. Is it a complete orphan or is something available?
TIA
Norm
Reply to
Norm Dresner
Loading thread data ...
Are you sure it isn't a J2 with a 1/2" capacity chuck?
Never heard of a J2-1/2
Reply to
Joe AutoDrill
IT CLEARLY SAYS: "SPINDLE JT#2-1/2" ON THE NAMEPLATE!!!
Sorry for shouting, but I'm not stupid. I said JT#2-1/2 and I meant it. I also said that it's 35 years old!
Norm
| Are you sure it isn't a J2 with a 1/2" capacity chuck? | | Never heard of a J2-1/2 | | -- | | | Regards, | Joe Agro, Jr. | (800) 871-5022 | (908) 542-0244 | Automatic / Pneumatic Drills:
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| Multiple Spindle Drills:
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| | V8013-R | |
| > I've got a (roughly) 35 year old AMT (American Machine Tool) bench drill | > press that's still working wonderfully and although I've thought | > occasionally of replacing it with a more modern DP with conveniences like | > a | > larger table, a ratchet drive on the table and possibly even variable | > speed, | > I still can't bring myself to part with this marvelous piece of machinery. | > | > BUT ... I'd like to purchase a better chuck. Some of the drilling I do | > with | > this beast is in the #70-80 range in both model working and PC board | > manufacture and while I don't yet have the tool to measure the runout | > (it's | > been ordered), I think that I need something with a little better | > precision, | > even if a smaller range. | > | > HOWEVER ... I don't think I've ever seen any product offered in the last | > 30 | > years for a JT#2-1/2. Is it a complete orphan or is something available? | > | > TIA | > Norm | > | |
Reply to
Norm Dresner
Does the chuck have a number stamped on it?
Tom
Reply to
Tom
| > | > I've got a (roughly) 35 year old AMT (American Machine Tool) bench drill | > press that's still working wonderfully and although I've thought | > occasionally of replacing it with a more modern DP with conveniences like a | > larger table, a ratchet drive on the table and possibly even variable speed, | > I still can't bring myself to part with this marvelous piece of machinery. | > | > BUT ... I'd like to purchase a better chuck. Some of the drilling I do with | > this beast is in the #70-80 range in both model working and PC board | > manufacture and while I don't yet have the tool to measure the runout (it's | > been ordered), I think that I need something with a little better precision, | > even if a smaller range. | > | > HOWEVER ... I don't think I've ever seen any product offered in the last 30 | > years for a JT#2-1/2. Is it a complete orphan or is something available? | > | > TIA | > Norm | | Does the chuck have a number stamped on it? | | Tom
There's an upper case "C" and "K" separated by a stylized drawing of an elephant head, ears & trunk and underneath is the size "13 m/m"
Norm
Reply to
Norm Dresner

Geez Norm, I din't recall anyone calling you stupid.
I am starting to suspect, though, given your reply.
35 years old would put in in an age that would have about half the guys here remembering seing this unit new in a showroom somewhere. It also makes it closer to brand new than a very large percentage of the tools in use in the shops of the guys here. The short of it...IT'S NOT ALL THAT OLD!
Split the chuck from the arbor, and compare the dimensions with the chart here
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. Strangely enough, it was found by putting the term "jacobs tapers" into Google. If you do not know how to separate the chuck and arbor, ask, or Google.arbor is a #2 and the drill was rated 1/2"
I'd bet a nickel (american one even) that the taper is a #2, and that the drill was rated for 1/2" capacity.
Have fun! Take yer meds!
Cheers Trevor Jones
Reply to
Trevor Jones
On the strength of that information, I will up my bet to TWO American nickels.
I seem to recall a similar brand mark that apeared on some India made chucks. 13 mm is soooooo close to 1/2"
Cheers Trevor Jones
Reply to
Trevor Jones
Not enough Nickel in an American nickel. GO Canadian! - I think they changed, but once were 100% Nickel.
Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder
Trevor J>
Reply to
Martin H. Eastburn
Ah but you can get the new American "Pecker Nickles" that they are recalling and that might be worth something someday :)
> Not enough Nickel in an American nickel. GO Canadian! - I think they > changed, but once > were 100% Nickel. > > Martin > Martin Eastburn > @ home at Lions' Lair with our computer lionslair at consolidated dot net > NRA LOH & Endowment Member > NRA Second Amendment Task Force Charter Founder > > > > Trevor J>> >> >>>| Does the chuck have a number stamped on it? >>>| >>>| Tom >>> >>>There's an upper case "C" and "K" separated by a stylized drawing of an >>>elephant head, ears & trunk and underneath is the size "13 m/m" >>> >>> Norm >> >> >> On the strength of that information, I will up my bet to TWO American >> nickels. >> >> I seem to recall a similar brand mark that apeared on some India made >> chucks. 13 mm is soooooo close to 1/2" >> >> Cheers >> Trevor Jones > >
Reply to
Glenn
Valium Norm... Calm down....
If you want help from others, you shouldn't flip out as they try to grasp your problem. Obviously, this is a bit unique and my guess is that it is a JT2.
Regards, Joe Agro, Jr. (800) 871-5022 (908) 542-0244 Automatic / Pneumatic Drills:
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Spindle Drills:
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V8013-R
Reply to
Joe AutoDrill
| > | > IT CLEARLY SAYS: "SPINDLE JT#2-1/2" ON THE NAMEPLATE!!! | > | > Sorry for shouting, but I'm not stupid. I said JT#2-1/2 and I meant it. I | > also said that it's 35 years old! | > | > Norm | | | Geez Norm, I din't recall anyone calling you stupid. | | I am starting to suspect, though, given your reply. | | 35 years old would put in in an age that would have about half the guys | here remembering seing this unit new in a showroom somewhere. It also | makes it closer to brand new than a very large percentage of the tools | in use in the shops of the guys here. The short of it...IT'S NOT ALL | THAT OLD! | | Split the chuck from the arbor, and compare the dimensions with the | chart here
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. Strangely enough, | it was found by putting the term "jacobs tapers" into Google. If you do | not know how to separate the chuck and arbor, ask, or Google.arbor is a | #2 and the drill was rated 1/2" | | I'd bet a nickel (american one even) that the taper is a #2, and that | the drill was rated for 1/2" capacity. | | Have fun! Take yer meds! | | Cheers | Trevor Jones
The label on the front of the DP has two lines, one for Spindle and one for capacity. The spindle line clearly says "JT#2-1/2" and the capacity line says "1/2 inch". Since there's a separate line for capacity, I saw no reason for them to have lied on the spindle line. BTW, this is an American-made machine produced in PA and I sincerely doubt there was any language problem.
I found the four-page "Instruction Manual" for the DP and unfortunately it says nothing about the size of any component.
BUT ... here's some interesting info from that manual that I had been unaware of:
1. The chuck is a force-fit onto a tapered spindle -- and the instruction manual describes it as a "Morse Taper", not a JT!
2. There's a nut that's threaded onto a cylindrical portion of the spindle above the chuck and the manual says to hold the pulley while turning the nut to force the chuck off the spindle.
SO ... Let's assume that we don't know what the taper of the spindle really is [i.e. it seems to be either Jacobs or Morse] and we're unsure of the "size". I'll try to get the chuck off the spindle this weekend and measure it.
Do you know of a chart for MT as well?
Norm
Reply to
Norm Dresner
|| > || > IT CLEARLY SAYS: "SPINDLE JT#2-1/2" ON THE NAMEPLATE!!! || > || > Sorry for shouting, but I'm not stupid. I said JT#2-1/2 and I meant it. | I || > also said that it's 35 years old! || > || > Norm || || || Geez Norm, I din't recall anyone calling you stupid. || || I am starting to suspect, though, given your reply. || || 35 years old would put in in an age that would have about half the guys || here remembering seing this unit new in a showroom somewhere. It also || makes it closer to brand new than a very large percentage of the tools || in use in the shops of the guys here. The short of it...IT'S NOT ALL || THAT OLD! || || Split the chuck from the arbor, and compare the dimensions with the || chart here
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. Strangely enough, || it was found by putting the term "jacobs tapers" into Google. If you do || not know how to separate the chuck and arbor, ask, or Google.arbor is a || #2 and the drill was rated 1/2" || || I'd bet a nickel (american one even) that the taper is a #2, and that || the drill was rated for 1/2" capacity. || || Have fun! Take yer meds! || || Cheers || Trevor Jones | | The label on the front of the DP has two lines, one for Spindle and one for | capacity. The spindle line clearly says "JT#2-1/2" and the capacity line | says "1/2 inch". Since there's a separate line for capacity, I saw no | reason for them to have lied on the spindle line. BTW, this is an | American-made machine produced in PA and I sincerely doubt there was any | language problem. | | I found the four-page "Instruction Manual" for the DP and unfortunately it | says nothing about the size of any component. | | BUT ... here's some interesting info from that manual that I had been | unaware of: | | 1. The chuck is a force-fit onto a tapered spindle -- and the instruction | manual describes it as a "Morse Taper", not a JT! | | 2. There's a nut that's threaded onto a cylindrical portion of the spindle | above the chuck and the manual says to hold the pulley while turning the nut | to force the chuck off the spindle. | | SO ... Let's assume that we don't know what the taper of the spindle really | is [i.e. it seems to be either Jacobs or Morse] and we're unsure of the | "size". I'll try to get the chuck off the spindle this weekend and measure | it. | | Do you know of a chart for MT as well? | | Norm
OOPS ! Sorry for asking before looking. I now see that the URL you referenced has both JT & MT on it. Thanks much
Norm
Reply to
Norm Dresner
| OOPS ! Sorry for asking before looking. I now see that the URL you | referenced has both JT & MT on it. Thanks much | | Norm
BTW -- the chart shows a JT between 2 & 3 that's called "2 short" there. It's possible that what AM&T called 2-1/2 is really 2-short.
Norm
Reply to
Norm Dresner
If your machine has a female morse taper (which is very common), just dump the current arbour and chuck, and replace both. The arbour should cost about $10 or less. The chuck is the expensive part (which you had to buy anyway).
Regards,
Robin
Reply to
Robin S.
Transpires that the drill press was made in Taiwan, so I would take how it has been described with a pinch of salt.
Reply to
Tom
According to Norm Dresner :
[ ... ]
The Morse taper is likely to be a female taper inside the spindle. There should be an arbor which fits into this taper in the spindle at one end, and which provides an appropriate Jacobs taper at the other end to fit the socket in the drill chuck.
And -- the only half sized *Morse* taper which I know of is the 4-1/2, used in L-00 spindle lathes. This is not really a Morse taper, but the ASA swept up three series of tapers to make a "standard" series, and there was too big a gap between MT-4 and MT-5, so they created an ASA taper 4-1/2 to fit into the Morse series.
I have *never* found a Jacobs taper in a half size.
Good Luck DoN.
Reply to
DoN. Nichols
| According to Norm Dresner : | > I've got a (roughly) 35 year old AMT (American Machine Tool) bench drill | > press that's still working wonderfully and although I've thought | > occasionally of replacing it with a more modern DP with conveniences like a | > larger table, a ratchet drive on the table and possibly even variable speed, | > I still can't bring myself to part with this marvelous piece of machinery. | > | > BUT ... I'd like to purchase a better chuck. Some of the drilling I do with | > this beast is in the #70-80 range in both model working and PC board | > manufacture and while I don't yet have the tool to measure the runout (it's | > been ordered), I think that I need something with a little better precision, | > even if a smaller range. | > | > HOWEVER ... I don't think I've ever seen any product offered in the last 30 | > years for a JT#2-1/2. Is it a complete orphan or is something available? | | I think that you're going to need two things to get there. | | 1) A truly accurate 1/2" chuck. (Does your drill press happen to | have a Morse taper in the spindle? If so, you can select other | Jacobs tapers than the JT 2 (which is more likely what you | have). | | Good accurate chucks with little runout are made by Albrecht, | and *some* of the clones are of equal quality, while others are | not. | | But -- none of these close down tight enough to grip much under | perhaps a 1/32" drill bit -- certainly not small enough to | handle a #70 or #80 drill bit. | [BIG SNIP]
Don
I had to drill a hole yesterday and was using a #75 drill. Using my 7-diopter OptiVisor I could see no wiggling of the end of the drill which should be an indication that the runout is pretty small. I've finally gotten a dial indicator and magnetic base and I intend to measure the runout as soon as I can get to it. Since the chuck does in fact close to (pretty close to) zero and if the runout is as small as I think it is, I'd probably be a fool to replace anything even though I'd love some more modern conveniences.
Norm
Reply to
Norm Dresner
| According to Norm Dresner : | > "Trevor Jones" wrote in message | | [ ... ] | | > 1. The chuck is a force-fit onto a tapered spindle -- and the instruction | > manual describes it as a "Morse Taper", not a JT! | > | > 2. There's a nut that's threaded onto a cylindrical portion of the spindle | > above the chuck and the manual says to hold the pulley while turning the nut | > to force the chuck off the spindle. | > | > SO ... Let's assume that we don't know what the taper of the spindle really | > is [i.e. it seems to be either Jacobs or Morse] and we're unsure of the | > "size". I'll try to get the chuck off the spindle this weekend and measure | > it. | | The Morse taper is likely to be a female taper inside the | spindle. There should be an arbor which fits into this taper in the | spindle at one end, and which provides an appropriate Jacobs taper at | the other end to fit the socket in the drill chuck. | | And -- the only half sized *Morse* taper which I know of is the | 4-1/2, used in L-00 spindle lathes. This is not really a Morse taper, | but the ASA swept up three series of tapers to make a "standard" series, | and there was too big a gap between MT-4 and MT-5, so they created an | ASA taper 4-1/2 to fit into the Morse series. | | I have *never* found a Jacobs taper in a half size. | | Good Luck | DoN. |
I'm planning on removing the chuck this weekend and measuring the taper. BTW, while nobody's ever found any reference to a half-size JT, there is something called a 2-short between #2 & #3.
Norm
Reply to
Norm Dresner
One alternative solution to drilling with very small bits is to make an auxilary table that will raise the work to the drill bit. The last one I saw was about 2 inches in diameter and used a rack and pinion to lift the table. it only had about a half inch of travel but would allow at least some feel, rather than guessing at the feed.
Cheers Trevor Jones
Reply to
Trevor Jones
I agree at this point..with Trevor
The simple way to find out..is to stick any MT2 taper gizmo in it and see if it fits properly.
Gunner, machine tool mechanic.
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences." - Proverbs 22:3
Reply to
Gunner

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