Fortunately I Have Loose Specs

I bought a Jacobs Super Chuck on Ebay, used. I had heard that the newer ones weren’t as good. When it arrived, it had a Moore jig borer taper stuck in it.

Jacobs makes cheap hardened wedges to get tapers out. They’re U-shaped pieces of metal that narrow toward the tips of the U. You put one on each side of the chuck, between the chuck and the taper. Then you press them toward each other with a vise or a hammer. I have heard people say a hydraulic press would work, but these things are very wimpy, so I don’t see how the additional force could be used.

The wedges were very blunt on the narrow ends, so I had to grind them to get them to slip past each other. I broke a couple. They bent like cheese. Finally, I put the taper on the anvil of my vise and beat one wedge into it with a blacksmith’s hammer, and out it popped.

Sadly, the wedges gouged my chuck. So I put it in the lathe and removed as much of the damage as I could. Here is the end product. I took off very little metal, and left some of the gouging in order to avoid going too deep.

The results are pretty good. The finish is not much worse than a new chuck. I used an AR tool (indexable carbide) and Ridgid Pipe Cutting Oil, and I didn’t expect great results from carbide, but it looks okay.

I started by facing the flat side. I was able to indicate the chuck in, but I could not index the flat side against anything, so it probably wasn’t all that perpendicular to the lathe’s axis. I don’t know if you can see it, but the flat side is not perfectly symmetrical. Oh well. Life will continue.

Once I had that done, I cleaned up the chamfer. I also did the rest of the face. The part that is angled. I had to break the compound loose, set the tool against the surface, and tighten the compound and tool post. I did the facing by moving the compound slide forward across the chuck, with the lathe in reverse. To go deeper, I drew the cross slide toward me. It worked out okay, so I guess you don’t always have to measure. None of these angles are critical.

I managed to stop the chuck (Jacobs, not lathe) a couple of times by cutting two deep. I think the little nick next to the rectangular-looking gouge occurred at that time, as the tool bit in. I removed most of the nick.

This was a lot of fun. I think the chuck is okay. The amount of metal I removed is like two sheets of aluminum foil.