|
Posted by Leon Fisk on March 14, 2006, 7:46 am
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On Fri, 10 Mar 2006 17:47:35 GMT, "Norm Dresner"
>I finally removed the chuck from the spindle on my circa 1973 AMT 1/2" bench
>drill press -- the one that has been the subject of several threads
>including one that concluded that I was absolutely crazy for believing a
>nameplate that said it has a JT#2-1/2 spindle.
>
>Well, here are the measurements -- along with specifications I've gotten
>from the web
>
>
>JT# Large Dia Small Dia Length
>#2 .5590" .4876" .8750"
>#2short .5488" .4876" .7500"
>#2-1/2 .677" .625" 1.055" <<--- my AMT
>#3 .8100" .7461" 1.2188
>
>It's also not anything close to any Morse taper either, nor a B+S.
>
>I guess it really is a JT#2-1/2 and nothing else.
>
>Which means that there's no way that I can replace the chuck with anything
>better today.
>
>Also, in removing the chuck, I discovered that the set screw that holds the
>pulley to the shaft was missing so all speeds under load were slower than I
>thought they were. I doubt that this had any effect on the runout, but I
>will measure it after replacing the chuck just to make sure that I haven't
>made it worse.
Hi Norm,
I've been following this discussion for the while and I
finally had to go take a look in the dungeon. I see some
more ideas/info has popped up since I wrote this too...
I have two presses wearing AMT badges and they are probably
the same as yours. Here is an image for comparison:
http://www.iserv.net/~lfisk/amt-pair.jpg
These were both made in Taiwan. See the following image of
one of the name plates and note "Made in" at the bottom of
the plate. The company American Machine and Tool Inc is in
PA, but these weren't made there.
http://www.iserv.net/~lfisk/amt-nameplate.jpg
One instruction sheet (that came with them) does indeed
mention using a Morse taper, the other machines sheet says
Jacobs taper. The two chucks are of different manufacture
and are inexpensive no names. Neither one is marked as to
the taper they use.
These were inexpensive presses and weren't even sold with
motors on them.
For anyone curious, here is a parts diagram showing the
chuck, quill, spindle, pulleys... It appears that you are
stuck with this taper, it is part of the spindle.
http://www.iserv.net/~lfisk/amt-diagram.gif
From the measurements you made and my trying a JT2 and JT33
on one of my presses (both too small, only other chucks I
had on hand), I would say that this is a JT6 taper. See this
file from Jacobs, which also has the "din" measurements
mention in another post:
http://www.jacobschuck.com/pdf/Technical-Information.pdf
They show the size progression as JT2 to JT33 to JT6 to JT3.
The JT6 is listed as:
Large Dia Small Dia Length
.678 .6241 1.000
My presses are really sloppy. If you lower the quill an inch
or so, you can grab the chuck and move it back-and-forth
maybe a 1/16 inch. Have you tried that on yours?
There is a set screw and locknut on the side of the casting,
but even adjusting that you can't get rid of the play. You
get what you pay for and these weren't much (shrug).
It looks like if you could find another JT6 taper chuck you
would be in business. I wouldn't bother on mine, not with
the slop I've got in the quills...
--
Leon Fisk
Grand Rapids MI/Zone 5b
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|
Posted by Norm Dresner on March 15, 2006, 9:10 am
Please log in for more thread options
| Hi Norm,
|
| I've been following this discussion for the while and I
| finally had to go take a look in the dungeon. I see some
| more ideas/info has popped up since I wrote this too...
|
| I have two presses wearing AMT badges and they are probably
| the same as yours. Here is an image for comparison:
|
| http://www.iserv.net/~lfisk/amt-pair.jpg
|
| These were both made in Taiwan. See the following image of
| one of the name plates and note "Made in" at the bottom of
| the plate. The company American Machine and Tool Inc is in
| PA, but these weren't made there.
|
| http://www.iserv.net/~lfisk/amt-nameplate.jpg
|
Yes, Leon, those are the exact same "models" that I have. I've posted my
scan of the "manual" in the dropbox at
http://www.metalworking.com
and the measurements I made in the accompanying text file.
Yes, it certainly appears to be a JT6. Knowing that, I searched Enco
http://www.use-enco.com
for JT6 chucks and came up with 4 ranging from $18 to $84 at
http://www.use-enco.com/CGI/INLMK32?PARTPG=INSRAR2
so there may be new chucks available after all.
Thanks very much for the info
Norm
|
|
Posted by Leon Fisk on March 15, 2006, 2:26 pm
Please log in for more thread options On Wed, 15 Mar 2006 14:10:01 GMT, "Norm Dresner"
>| Hi Norm,
>|
>| I've been following this discussion for the while and I
>| finally had to go take a look in the dungeon. I see some
>| more ideas/info has popped up since I wrote this too...
>|
>| I have two presses wearing AMT badges and they are probably
>| the same as yours. Here is an image for comparison:
>|
>| http://www.iserv.net/~lfisk/amt-pair.jpg
>|
>| These were both made in Taiwan. See the following image of
>| one of the name plates and note "Made in" at the bottom of
>| the plate. The company American Machine and Tool Inc is in
>| PA, but these weren't made there.
>|
>| http://www.iserv.net/~lfisk/amt-nameplate.jpg
>|
>
>Yes, Leon, those are the exact same "models" that I have. I've posted my
>scan of the "manual" in the dropbox at
> http://www.metalworking.com
>and the measurements I made in the accompanying text file.
>
>Yes, it certainly appears to be a JT6. Knowing that, I searched Enco
> http://www.use-enco.com
>for JT6 chucks and came up with 4 ranging from $18 to $84 at
> http://www.use-enco.com/CGI/INLMK32?PARTPG=INSRAR2
>
>so there may be new chucks available after all.
>
>Thanks very much for the info
Hi Norm,
Is you're press badged as made in Taiwan too (now that you
know where to look)? I don't think mine are quite as old as
yours, probably bought in the mid to late 70's. They are
subtly different too. The slightly newer one doesn't have
the nut for removing the chuck, nor any threads for one. The
manual that came with that press still pictures it in the
parts diagram/list though. Instructions for removing the
chuck still tell you to turn the non-existent nut too. This
is also the manual that calls it a Jacobs taper. Just
eyeballing them though it appears to be the same taper. I
only popped off the chuck on the press that has a threaded
nut :)
You might want to check how much play there is when you run
the quill down and inch or two. As I mentioned, mine are
really loose. I don't know what the other readers opinions
are, but for drilling tiny holes I don't think this would be
a good thing.
--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email
|
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>drill press -- the one that has been the subject of several threads
>including one that concluded that I was absolutely crazy for believing a
>nameplate that said it has a JT#2-1/2 spindle.
>
>Well, here are the measurements -- along with specifications I've gotten
>from the web
>
>
>JT# Large Dia Small Dia Length
>#2 .5590" .4876" .8750"
>#2short .5488" .4876" .7500"
>#2-1/2 .677" .625" 1.055" <<--- my AMT
>#3 .8100" .7461" 1.2188
>
>It's also not anything close to any Morse taper either, nor a B+S.
>
>I guess it really is a JT#2-1/2 and nothing else.
>
>Which means that there's no way that I can replace the chuck with anything
>better today.
>
>Also, in removing the chuck, I discovered that the set screw that holds the
>pulley to the shaft was missing so all speeds under load were slower than I
>thought they were. I doubt that this had any effect on the runout, but I
>will measure it after replacing the chuck just to make sure that I haven't
>made it worse.