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

JT 2-1/2 Spindle Chuch replacement
 

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: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R


"Norm Dresner" wrote in message
...
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

JT 2-1/2 Spindle Chuch replacement
 

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

"Joe AutoDrill" wrote in message
news:0lINf.852$ZL1.818@trndny09...
| 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: http://www.AutoDrill.com
| Multiple Spindle Drills: http://www.Multi-Drill.com
|
| V8013-R
|
|
| "Norm Dresner" wrote in message
| ...
| 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
|
|
|

JT 2-1/2 Spindle Chuch replacement
 

Norm Dresner wrote:

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

JT 2-1/2 Spindle Chuch replacement
 

"Tom" wrote in message
...
| Norm Dresner wrote:
|
| 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

JT 2-1/2 Spindle Chuch replacement
 

Norm Dresner wrote:

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 http://www.newmantools.com/tech/taper.htm . 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

JT 2-1/2 Spindle Chuch replacement
 

Norm Dresner wrote:

| 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

JT 2-1/2 Spindle Chuch replacement
 

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 Jones wrote:
Norm Dresner wrote:


| 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

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
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JT 2-1/2 Spindle Chuch replacement
 

Ah but you can get the new American "Pecker Nickles" that they are recalling
and that might be worth something someday :)

"Martin H. Eastburn" wrote in message
...
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 Jones wrote:
Norm Dresner wrote:


| 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

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet
News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+
Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption
=----

JT 2-1/2 Spindle Chuch replacement
 

"Norm Dresner" wrote in message
...
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!

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: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R

JT 2-1/2 Spindle Chuch replacement
 

"Trevor Jones" wrote in message
...
| Norm Dresner wrote:
|
| 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 http://www.newmantools.com/tech/taper.htm . 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

JT 2-1/2 Spindle Chuch replacement
 

"Norm Dresner" wrote in message
...
| "Trevor Jones" wrote in message
| ...
|| Norm Dresner wrote:
||
|| 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 http://www.newmantools.com/tech/taper.htm . 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

JT 2-1/2 Spindle Chuch replacement
 

"Norm Dresner" wrote in message
...
| 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

JT 2-1/2 Spindle Chuch replacement
 

"Norm Dresner" 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!

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

JT 2-1/2 Spindle Chuch replacement
 

Joe AutoDrill wrote:

"Norm Dresner" wrote in message
...
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!

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.

Transpires that the drill press was made in Taiwan, so I
would take how it has been described with a pinch of salt.

JT 2-1/2 Spindle Chuch replacement
 

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.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

JT 2-1/2 Spindle Chuch replacement
 

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.

2) A sensitive drill adaptor to go in that chuck. This consists
of a (typically) 0-1/8" Albrecht chuck mounted on a sliding
spindle which is chucked in the drill press chuck. There is a
ring just behind the chuck mounted to the shaft with a ball
bearing between them, which allows you to grip the ring and to
pull the sliding spindle down against a light spring in the
adaptor, so you can control the drilling pressure with these
tiny bits with at least some feel. The normal spider for
feeding the drill press's spindle will give you worse than no
feel for the drilling force, and will cost you a lot of tiny
drill bits.

An example of this sort of thing can be found in eBay auction
#7595222558. This one happens to only go up to 1/16" instead of
1/8" but should suffice for your needs.

This was found by an eBay search on "sensitive drill" (with
the quote marks -- without, you get thousands of hits, including
some eBook on "mastering premature ejaculation". :-)

This search also brings up some sensitive drill presses, though
only one looks like one that I would choose for serious work,
the one in auction #7596471948, though auction #8907848616 looks
interesting. It would need some additional equipment to power
it.

I, personally, have a Cameron Micro Precision drill press, which
works quite well for the purpose -- but I got it new back around 1973 or
so, when the price was a lot more reasonable. However, keep watching
the eBay auctions, as interesting ones come up from time to time. A
good sensitive drill press would be a far better choice for you than
trying to use an adaptor in a regular drill press. And -- it would let
you keep your regular drill press for normal size drilling. Among other
things, drilling in the #70 and smaller size range really needs a higher
spindle speed than you can coax out of most drill presses which were not
made as sensitive drill presses from the start.

Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

JT 2-1/2 Spindle Chuch replacement
 

"DoN. Nichols" wrote in message
rvers.com...
| 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

JT 2-1/2 Spindle Chuch replacement
 

"DoN. Nichols" wrote in message
rvers.com...
| 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

JT 2-1/2 Spindle Chuch replacement
 

Norm Dresner wrote:

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

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

JT 2-1/2 Spindle Chuch replacement
 

On Thu, 02 Mar 2006 19:51:41 -0700, Trevor Jones
wrote:

Norm Dresner wrote:

| 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

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

JT 2-1/2 Spindle Chuch replacement
 

According to Norm Dresner :

[ ... ]

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.

That I find amazing. What brand of 1/2" drill chuck is it which
closes down to grip a #75 drill bit?.

Can you check whether it will grip a #80?

If it does not, you can go for the sensitive adaptor (either the
one in the eBay auction to which I pointed, or another similar one)
which will also give you more control and feel in feeding the drill bit.

I've done down to #70 in the tailstock of my small lathe -- an
Emco-Maier Compact-5/CNC, with a 0-1/8th Albrecht chuck on a #1 MT
arbor. And that worked well enough in 12L14 steel -- but I kept
worrying about the lack of feel that the leadscrew gave me with that
tiny a drill bit, so I was *very* careful.

Good Luck,
DoN.

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--- Black Holes are where God is dividing by zero ---

JT 2-1/2 Spindle Chuch replacement
 

According to Trevor Jones :
Norm Dresner wrote:

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.

[ ... ]

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.

That is actually quite similar to many of the sensitive drill
presses to be found on eBay currently.

I agree that feel is an important consideration with such tiny
drill bits.

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

JT 2-1/2 Spindle Chuch replacement
 

According to Norm Dresner :

[ ... ]

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.

O.K. That could be what they used -- though Lord only knows why
they would mark that on the machine, when there is a Morse taper socket
in the spindle to allow you to change arbors for whatever size your
favorite drill chuck happens to take.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

JT 2-1/2 Spindle Chuch replacement
 

replying to Norm Dresner, drillpress wrote:
I also have a JT 2 1/2 Chuck on a Columbia 515 drill press made in Taiwan. I
compared the taper dimensions with the published Jacobs taper dimensions and
found that it was likely consistant with a current Jacobs 6 taper. I
purchased a new Jacobs 6 chuck and it fit perfectly. I have no idea how that
conversion can be explained.

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for full context, visit https://www.polytechforum.com/metalw...nt-478760-.htm

JT 2-1/2 Spindle Chuch replacement
 

replying to drillpress, Chitty wrote:
Looking for info on a JT 2 1/2 taper drill chuck also.
Mine is a similar Taiwan marketed in North America.
The Jacobs 2 1/2 taper is its very own taper but used widely in the era on
Japanese configuration but appears to be no longer available these days. The
JT 6 is close but a different bird.
Anyone have any luck?
The spindle on my machine is a one piece unit with the lower end being a male
JT 2 1/2 that is intended to mount the appropriate chuck directly to the
spindle without the typical double ended arbor between the spindle and chuck.
Only option Ive found is to pull the spindle and hope a machinist can
convert the spindle without error to a modern available taper.
Share your info please!

--
for full context, visit https://www.polytechforum.com/metalw...nt-478760-.htm