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View Full Version : How to remove Jacobs chuck arbor?



BigDave
11-08-2001, 03:21 PM
I may be buying a Jacobs 20N big lathe drill chuck with an MT 5 arbor.

I need a 4MT arbor.

Is it difficult to remove an old drill chuck arbor?

SGW
11-08-2001, 03:35 PM
It all depends....

There are two common ways of doing it. One is to use chuck removal wedges. They're a pair of thin slotted wedges that fit around the arbor just above the chuck. IF there is a shoulder on the arbor for the wedges to bear against, this is probably the best/easiest way of doing it. I think MSC, among others, sells the wedges, or you could probably make up a pair of your own. They're about 1/8" thick at the thick end, tapering down to nothing at the thin slotted end and are maybe 1 1/2" long. You need a pair so the angles cancel out and the top and bottom bearing surfaces are parallel.

If there is no shoulder on the arbor...it gets more difficult. In that case, probably the best way is to drill a hole through the bottom of the drill chuck into the space above the top of the arbor (the chuck is soft there so it is drillable), set the chuck up in an arbor press, and press the arbor out with a pin going through the hole. You want the hold as big as conveniently possible so you can use as big a pin as possible. Probably a suitably-sized dowel pin would be good.

BigDave
11-08-2001, 03:40 PM
Thanks for the info...here is the photo of the one I am trying to acquire. I can't see from the photo of there is a ledge at the end of the arbor.

Sounds like if wedges can be used it sure saves a hassle!

http://abacus.sj.ipixmedia.com/abc/M28/5ce31d4e9fa9a100f52e02bac/i-1.JPG

docn8as
11-08-2001, 11:54 PM
have drilled large hole thru chuck & driven arbor off w/ 32 oz. hammer & hardened pin......swore i would never mount another w/out drilling hole first.....just mounted one last week w/ out drilling hole!!!remembered just as lead hammer hit!! so much for getting old!!!!!..one years experience 50 times!
best wishes
docn8as

Thrud
11-09-2001, 12:17 AM
Big Dave,

I have all the Jacobs wedges - none will fit that monster! Are you sure it is not on a 1.5" x 8TPI shank? Looks like the old lathe chuck for the threaded noses.

Dave

C. Tate
11-09-2001, 07:43 AM
Dave
All of the chucks I have seen will have the taper and capacity information stamped on the nose just below the nut. If this thing does have a threaded arbor it will tell you there.

To remove the taper you can try a little heat to the chuck before pressing or driving the arbor off. Use mapp or propane sparingly you do not want to get this thing to hot. You can freeze this thing before heating the chuck to get the best of both worlds the cold will shrink up the arbor and the heat will expand the chuck (in theory).

bighammer
11-29-2001, 01:54 PM
put chuck under heater or heat lamp, keep dry, don't use hot water, when too hot to hold without gloves,pack shank in dry ice.hold chuck in wood saddles in vice use vice-gripes and hahher on shank. grab tang and you won,t mar taper.

bighammer
11-29-2001, 02:00 PM
dam,can't spell hammer!

kap pullen
11-29-2001, 02:41 PM
put an endmill in it and start to cut......