# Removing Jacobs 18N from MT5



## yugami (Aug 25, 2013)

I purchases a box of Misc tooling at a live auction and burried in it was a Jacobs 18N superchuck (3/4" capacity ball bearing chuck) on a MT5 arbor.

I looked up the wedges to remove an 18N and the online instructions I found said to get both the No 3 and No 6 wedges.  Ordered and received, however the MT5 arbor is significantly thicker than the slot in the wedges.  And I don't feel its safe to open up the wedges as that would leave them very thin.

Anyone know the right thing to buy to get this off?  I have a J4->MT2 for my Logan that I want to put this on.


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## 4GSR (Aug 25, 2013)

Open up the jaws on the chuck.  Drill a 1/2" or 5/8" hole thru the ID of the chuck body to the arbor.  Take a large punch that will fit into the drilled hole and with a big hammer pop the arbor out of the chuck body.  Heat may be used if the arbor is really stuck.  Too high of heat will distort the chuck body.  If that don't work, cut off the arbor and bore out some of the metal and drive out the rest from the other end thru the hole drilled earlier in the chuck body.

Most of my Jacobs drill chucks are done this way.  Makes it easier to change out arbors when needed.


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## Tony Wells (Aug 26, 2013)

If you want to sacrifice the 5MT, chuck a piece of 3/4" stock, or a 3/4" hex key in the chuck, then chuck that in the lathe, and part if off, and drill it out. If you leave a little of the shoulder on it for the wedges, it won't be tight after you drill out most of it. If you want to salvage the MT shank, then follow the advice above, or try again on getting the correct wedges. They work fine if you get the right ones.


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## OldMachinist (Aug 26, 2013)

The 18N has a #4 Jacobs taper mount. There are no wedges for this size. Drilling a hole thru the chuck body and pressing it out from the jaw end is the recommended removal.

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


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## yugami (Aug 26, 2013)

OldMachinist said:


> The 18N has a #4 Jacobs taper mount. There are no wedges for this size. Drilling a hole thru the chuck body and pressing it out from the jaw end is the recommended removal.
> 
> http://www.jacobschuck.com/drill-chuck-install.asp



I skimmed that article, saw the wedge part and stopped reading.  Didn't even get to the drill it out bit or I would have been done last night.

Thanks everyone


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## papermaker (Aug 26, 2013)

worked pretty good on the Jacobs chuck I had. I think that chucking it up in the lathe may have been easier to drill out the center of the chuck. Try to figure the correct depth so as not to ruin the taper. You never know when it could come in handy.


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