I have this nice 25 yr old Jet 1/2" drill press--has a nicely machined
Jacobs style chuck-(16mm)--a couple of years ago, it started slipping
while tightening it up. you get it fairly tight with the key,, and then
you can just keep on turning the key--w/o it getting any
tighter---although you have to turn the chuck key further than "normal"
to loosen the chuck.. Inspecting the innards doesn't reveal any obvious
defects..Do I need to clean one area & lube another???

"Jerry Wass" wrote in message
...

I have this nice 25 yr old Jet 1/2" drill press--has a nicely machined
Jacobs style chuck-(16mm)--a couple of years ago, it started slipping
while tightening it up. you get it fairly tight with the key,, and then
you can just keep on turning the key--w/o it getting any
tighter---although you have to turn the chuck key further than "normal"
to loosen the chuck.. Inspecting the innards doesn't reveal any obvious
defects..Do I need to clean one area & lube another???

You have probably sprung the jaws.
They are replaceable.

JC

"John R. Carroll" wrote in message
...

"Jerry Wass" wrote in message
...

I have this nice 25 yr old Jet 1/2" drill press--has a nicely machined
Jacobs style chuck-(16mm)--a couple of years ago, it started slipping
while tightening it up. you get it fairly tight with the key,, and then
you can just keep on turning the key--w/o it getting any
tighter---although you have to turn the chuck key further than "normal"
to loosen the chuck.. Inspecting the innards doesn't reveal any obvious
defects..Do I need to clean one area & lube another???

You have probably sprung the jaws.
They are replaceable.

JC


More likely the ring gear is slipping on the body.

"Buerste" wrote in message
...

"John R. Carroll" wrote in message
...

"Jerry Wass" wrote in message
...

I have this nice 25 yr old Jet 1/2" drill press--has a nicely machined
Jacobs style chuck-(16mm)--a couple of years ago, it started slipping
while tightening it up. you get it fairly tight with the key,, and then
you can just keep on turning the key--w/o it getting any
tighter---although you have to turn the chuck key further than "normal"
to loosen the chuck.. Inspecting the innards doesn't reveal any obvious
defects..Do I need to clean one area & lube another???

You have probably sprung the jaws.
They are replaceable.

JC


More likely the ring gear is slipping on the body.
I think you mean the ring-gear sleeve is slipping on the nut.
--
Regards,

Chas.

(To email me, replace "xxx" with letters tango papa golf.)

"Chas" wrote in message
...

"Buerste" wrote in message
...

"John R. Carroll" wrote in message
...

"Jerry Wass" wrote in message
...

I have this nice 25 yr old Jet 1/2" drill press--has a nicely machined
Jacobs style chuck-(16mm)--a couple of years ago, it started slipping
while tightening it up. you get it fairly tight with the key,, and
then you can just keep on turning the key--w/o it getting any
tighter---although you have to turn the chuck key further than "normal"
to loosen the chuck.. Inspecting the innards doesn't reveal any obvious
defects..Do I need to clean one area & lube another???

You have probably sprung the jaws.
They are replaceable.

JC


More likely the ring gear is slipping on the body.
I think you mean the ring-gear sleeve is slipping on the nut.
--
Regards,

Chas.

(To email me, replace "xxx" with letters tango papa golf.)


Exactly. I don't see how it could be in the jaws. However, when I have a
chuck act up in the slightest...it gets replaced. All my production
machines have Jacobs chucks and we used to repair them but it just isn't
worth it anymore.

On Dec 4, 5:23*am, "Buerste" wrote:

[regarding a nontightenable Jacobs type chuck;
the ring-gear sleeve is slipping on the nut]

... we used to repair them but it just isn't
worth it anymore.

But, for the edification of the original poster, it IS
instructive to disassemble and admire the internal
construction. Lightly knurling the inside surface of the
geared sleeve would solve the problem, and a
freshly lubed worn-in Jacobs chuck is SO smooth
in operation after a rebuild, it's worth the effort.
Unless, of course, you have paying customers waiting.

Jacobs offers takeapart instructions

http://www.jacobschuck.com/drill-chuck-repair.asp

Reassembly is easier if you heat the sleeve on a hot plate.

"Buerste" wrote in message
...

"Chas" wrote in message
...

"Buerste" wrote in message
...

"John R. Carroll" wrote in message
...

"Jerry Wass" wrote in message
...

I have this nice 25 yr old Jet 1/2" drill press--has a nicely machined
Jacobs style chuck-(16mm)--a couple of years ago, it started slipping
while tightening it up. you get it fairly tight with the key,, and
then you can just keep on turning the key--w/o it getting any
tighter---although you have to turn the chuck key further than
"normal"
to loosen the chuck.. Inspecting the innards doesn't reveal any
obvious defects..Do I need to clean one area & lube another???

You have probably sprung the jaws.
They are replaceable.

JC


More likely the ring gear is slipping on the body.
I think you mean the ring-gear sleeve is slipping on the nut.
--
Regards,

Chas.

(To email me, replace "xxx" with letters tango papa golf.)


Exactly. I don't see how it could be in the jaws.

I've seen many a chuck where the operator chucked the tool improperly in
order to get an extra quarter inch of extension rather than use the proper
tool.
The jaws end up a mess and the chuck doesn't tighten properly until you
rebuild it.

With todays modern drilling technology, I avoid Jacobs like the plague in
favor of collet chucks.
Through the tool coolant is becoming a defacto standard configuration and
tools like M.A. Fords Twister XD series have ground shanks, are solid
carbide and coated so that you can run feeds and speeds that have been
unheard of until recently. This sort of drilling technology is also
expensive. A .421 5X drill will drill two inches deep in A286 without
pecking at 30 inches per minute and give you thousands of holes but the
drill is $186.00 - or was six months ago. You won't do that with a Jacobs or
even an Albrecht but it's easy with an ER32.

JC

"John R. Carroll" wrote in message
...

"Buerste" wrote in message
...

"Chas" wrote in message
...

"Buerste" wrote in message
...

"John R. Carroll" wrote in message
...

"Jerry Wass" wrote in message
...

I have this nice 25 yr old Jet 1/2" drill press--has a nicely
machined Jacobs style chuck-(16mm)--a couple of years ago, it started
slipping
while tightening it up. you get it fairly tight with the key,, and
then you can just keep on turning the key--w/o it getting any
tighter---although you have to turn the chuck key further than
"normal"
to loosen the chuck.. Inspecting the innards doesn't reveal any
obvious defects..Do I need to clean one area & lube another???

You have probably sprung the jaws.
They are replaceable.

JC


More likely the ring gear is slipping on the body.
I think you mean the ring-gear sleeve is slipping on the nut.
--
Regards,

Chas.

(To email me, replace "xxx" with letters tango papa golf.)


Exactly. I don't see how it could be in the jaws.

I've seen many a chuck where the operator chucked the tool improperly in
order to get an extra quarter inch of extension rather than use the proper
tool.
The jaws end up a mess and the chuck doesn't tighten properly until you
rebuild it.

With todays modern drilling technology, I avoid Jacobs like the plague in
favor of collet chucks.
Through the tool coolant is becoming a defacto standard configuration and
tools like M.A. Fords Twister XD series have ground shanks, are solid
carbide and coated so that you can run feeds and speeds that have been
unheard of until recently. This sort of drilling technology is also
expensive. A .421 5X drill will drill two inches deep in A286 without
pecking at 30 inches per minute and give you thousands of holes but the
drill is $186.00 - or was six months ago. You won't do that with a Jacobs
or even an Albrecht but it's easy with an ER32.

JC


Ah, I see where you are going with the jaws!

"Buerste" wrote:

Ah, I see where you are going with the jaws!

Jaws are HSS technology. We have progressed.

Wes