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Hobbyman
06-18-2012, 06:43 PM
I have never done this. I made up a collar that matches the OD sleeve of the chuck and tried pushing with the tailstock screw. It didn't move. how much tonnage do I need? I have about 40 tons if I need but I want to salvage this much abused unit not destroy it.

sasquatch
06-18-2012, 07:07 PM
I'm pretty sure there are two different designs that require two different dismantle proceedures.

Some one here will know for sure.

JCHannum
06-18-2012, 07:32 PM
Instructions are here;

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

It takes a bit of force to get things moving, but once freed up the sleeve will move easily. As long as the jaws are extended as instructed, there is no danger of damage. The recent series of ball bearing chucks differ internally from earlier versions, but the basics of dismantling are the same.

beckley23
06-18-2012, 07:42 PM
Just went through this with a 16N Jacobs chuck. You're going to need an arbor press to push the sleeve off. Once I got the sleeve off, I was able to find out the problem, a major chip out on the nut. Price the repair parts at approx 170.00, new chuck is approx 210.00. With the reputation that Jacobs now has, I opted to buy a new Accupro, made in Spain, from MSC for considerably less.
There are two versions of the repair kits available for Jacobs, one has the parts that can basically be bought individually and the other, basically replaces all the internal parts. Look on your chuck and see if it has repair kit # near one the chuck key holes; that's the expensive one.
Harry

lazlo
06-18-2012, 08:45 PM
Not tons -- maybe a couple of hundred lbs. I open the Jacobs chucks in a benchtop arbor press with one arm.

If you hold the drill chuck by the tang and look down at it, you can see the seam where the shell fits on the main body. That's the part you're pressing off. Just turn an aluminum doughnut that catches up to that edge, and press the body off the shell by the chuck jaws.

Once the shell starts to pass the thrust bearing races, go carefully, because the ball bearings are free floating in the split race, and will go flying.

You can buy the rebuild kits for the Jacobs (new jaws, balls, and split race) for $25 - $35 on Ebay.

Hobbyman
06-18-2012, 09:16 PM
Not tons --
Once the shell starts to pass the thrust bearing races, go carefully, because the ball bearings are free floating in the split race, and will go flying.

You can buy the rebuild kits for the Jacobs (new jaws, balls, and split race) for $25 - $35 on Ebay.

thanks ... A small sledge with one blow did it. As for the little balls... no worries they are held in by caked rust. I had saved this unit by soaking in oil years ago but in a welding shop things get neglected. I brought it home as a basket case and that is certainly what it is.