xray wrote:
I have a Jacobs 14N 1/2" chuck for the tailstock of my lathe. The MT2
arbor it is mounted on has spun in some past life and is a bit munged
up.

I ordered a new JT3 to MT2 arbor for it, but now I find I can't budge
the existing arbor out of the chuck. It's not rusty. I've soaked it
penetrating oil for about a day. I tried heating it with a torch and
then later by baking it in the oven. Quickly cooled the arbor with a wet
sponge while the chuck was still several hundred degrees from the oven.
I've succeded in slightly bending a Starrett center punch trying to
pound the arbor through the center hole in the chuck.

Any tips on things I could try to break up this long-term relationship?


I ran into exactly that same problem a few months back. Like yours,
there was no shoulder to bear wedges against. I did the hammer and punch
thing, the soak in penatrant & bigger hammer and another punch (the
first one started to bend) trick, and finally the hardened steel pin and
10 ton press trick. None budged the chuck. In frustration, and figuring
the chuck may be lost anyhow, I cut the arbor off flush, chucked the
chuck in my lathe and drilled and then began carefully boring out the
remains. I tried to approach slowly, hoping that I could cut into what
was left of the arbor thin enough to collapse with a chisel, without
hitting the chuck. As I apporached what i thought would be close enough,
I noticed that there was a pattern in the bore. A close look revealed
that the end of the arbor was THREADED! Duh. Color me stupid. Not sure
why that possibility never occured to me, but my excuse was that I did
not put the chuck on there, so i couldn't have known. A few taps with a
chisel and what remained of the arbor easily unscrewed. So if you did
not put that chuck on there yourself, you may want to double check...



-AL A.

Since we sell used machine tools I have solved this problem at least a
dozen times. Saw the arbor off approximately flush with the chuck. You
were going to throw it away any way. Run the chuck up tight and tighten
it with the chuck key. Chuck it in your lathe spindle chuck and drill a
pilot hole for something like a 5/16" - 18 thread and tap it. Put a
small 1/2" drive socket over the Jacobs chuck arbor drive end and
screw a bolt through that into the newly threaded hole. That bolt will
draw the tapered stub out with almost no torque on the wrench. It is
even more cost effective when you salvage an Albrecht chuck this way.
Leigh at MarMachine

On 6 May 2006 13:05:28 -0700, wrote:

Since we sell used machine tools I have solved this problem at least a
dozen times. Saw the arbor off approximately flush with the chuck. You
were going to throw it away any way. Run the chuck up tight and tighten
it with the chuck key. Chuck it in your lathe spindle chuck and drill a
pilot hole for something like a 5/16" - 18 thread and tap it. Put a
small 1/2" drive socket over the Jacobs chuck arbor drive end and
screw a bolt through that into the newly threaded hole. That bolt will
draw the tapered stub out with almost no torque on the wrench. It is
even more cost effective when you salvage an Albrecht chuck this way.
Leigh at MarMachine
All us "cheap screws" out here appreciate this tip.

Thanks

Unka George
(George McDuffee)

There is something to be said for government by a great aristocracy
which has furnished leaders to the nation in peace and war for generations;
even a democrat like myself must admit this.

But there is absolutely nothing to be said for government by a plutocracy,
for government by men very powerful in certain lines and gifted with the "money touch,"
but with ideals which in their essence are merely those of so many glorified pawnbrokers.

Theodore Roosevelt (1858-1919), U.S. Republican (later Progressive) politician, president. Letter, 15 Nov. 1913.

According to :
Since we sell used machine tools I have solved this problem at least a
dozen times. Saw the arbor off approximately flush with the chuck. You
were going to throw it away any way. Run the chuck up tight and tighten
it with the chuck key. Chuck it in your lathe spindle chuck and drill a
pilot hole for something like a 5/16" - 18 thread and tap it. Put a
small 1/2" drive socket over the Jacobs chuck arbor drive end and
screw a bolt through that into the newly threaded hole. That bolt will
draw the tapered stub out with almost no torque on the wrench. It is
even more cost effective when you salvage an Albrecht chuck this way.

A good one. And another related one, which starts the same has
you installing a Zerk fitting into the threaded hole, and pumping in
grease to pop it free. (Of course, that would not work with this one,
because I remember mention of it having a hole in the body which reaches
through to the arbor, so the grease would simply fill the chuck --
unless you could also tap that hole and put in a screw to plug the hole.

I'm going to be trying the Zerk and grease trick on an arbor
which a friend got from eBay with the wrong sized arbor for his lathe.
It also has too small a shoulder for the wedges to work. And if the
grease fails, there is already that threaded hole made for the Zerk to
try your trick on -- complete with nicely grease-lubricated threads to
help the process. :-)

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 ---

Maybe a bingo there - My wood lathe does screw on a chuck or a B.B. center.

Then - chuck a hex key or such - into the chuck - put it in the vice and
grab on the tang to turn...

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
IHMSA and NRA Metallic Silhouette maker & member


Al A. wrote:
xray wrote:

I have a Jacobs 14N 1/2" chuck for the tailstock of my lathe. The MT2
arbor it is mounted on has spun in some past life and is a bit munged
up.
I ordered a new JT3 to MT2 arbor for it, but now I find I can't budge
the existing arbor out of the chuck. It's not rusty. I've soaked it
penetrating oil for about a day. I tried heating it with a torch and
then later by baking it in the oven. Quickly cooled the arbor with a wet
sponge while the chuck was still several hundred degrees from the oven.
I've succeded in slightly bending a Starrett center punch trying to
pound the arbor through the center hole in the chuck.

Any tips on things I could try to break up this long-term relationship?


I ran into exactly that same problem a few months back. Like yours,
there was no shoulder to bear wedges against. I did the hammer and punch
thing, the soak in penatrant & bigger hammer and another punch (the
first one started to bend) trick, and finally the hardened steel pin and
10 ton press trick. None budged the chuck. In frustration, and figuring
the chuck may be lost anyhow, I cut the arbor off flush, chucked the
chuck in my lathe and drilled and then began carefully boring out the
remains. I tried to approach slowly, hoping that I could cut into what
was left of the arbor thin enough to collapse with a chisel, without
hitting the chuck. As I apporached what i thought would be close enough,
I noticed that there was a pattern in the bore. A close look revealed
that the end of the arbor was THREADED! Duh. Color me stupid. Not sure
why that possibility never occured to me, but my excuse was that I did
not put the chuck on there, so i couldn't have known. A few taps with a
chisel and what remained of the arbor easily unscrewed. So if you did
not put that chuck on there yourself, you may want to double check...



-AL A.

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