Kitagawa chuck

Sell it on ebay, for sure.

Where were the runout issues? Worn out jaws? Worn out spiral? Or have you checked?

Gunner

The methodology of the left has always been:

1. Lie
2. Repeat the lie as many times as possible
3. Have as many people repeat the lie as often as possible
4. Eventually, the uninformed believe the lie
5. The lie will then be made into some form oflaw
6. Then everyone must conform to the lie

Look at my previous post. I have 3 6" chucks with TIR > .04. Two came wi th the late. One I made my self when I was parting off a piece of 3" alumi num rod and the rod pulled out and crashed the lathe.

I would keep your bad chuck for those challenging operations where one does n?t want to sacrifice the good chuck

Gunner: do you know how to take the chucks apart? I might be able to make a good chuck out of thee bad chucks.

Try taking it apart and adding a shim wrapped around the stud which centers the scroll plate to minimize its ability to shift.

Also -- do you get this bad a variation even if you always use the same socket for the chuck key? Typically, one of the three is marked with a '0' or some similar marking. (And some even have only the one socket.)

If you can get the runout rather repeatable with the shim stock (which reduces how much the scroll shifts around when being tightened), then it would be worth while to use a toolpost grinder to face the jaws (while loaded) for better centering. The loading can be with a special fixture, or by putting three equal width spacers between the angled faces of the jaws while tightening the chuck. (You can't just set the jaws where you want and grind way, because they need the pre-loading to be repeatably on center.

Enjoy, DoN.

[ ... ]

I'm not Gunner, but for a standard 3-jaw chuck, assuming a backplate instead of one made to thread directly onto the spindle with the base casting, you:

1) Unbolt and remove the backplate. (Mark it so you can reinstall it in the same orientation later.) 2) Look for three screws securing a flat steel plate in the bottom of the cavity thus revealed, and remove those (idealy marking so you can put it back in in the same orientation. 3) Once that is off, you will probably see the inside end of the square key hole parts which will include a bevel gear on the inside end. These engage a larger bevel gear on the back side of the scroll plate. You will have to examine them to see just how they are secured. Perhaps with projections on the plate you removed, or perhaps with other things which need to be removed. 4) Once these are out, you can pull the scroll plate and clean it with a good solvent and a brass wire brush, and clean the teeth on the back of the chuck jaws. Clean everything in the back of the chuck too. 5) Trial fit the scroll plate back in the chuck, and check with a feeler gauge to see how much play there is between the center of the plate and the projection in the center of the chuck. Get some shim stock half that thickness, cut it to a width matching the thickness of the scroll plate in the center, and wrap it around the center projection of the chuck. put the scroll plate back, and see whether the plate can turn easily on it. Then put an appropriate oil or grease on the scroll plate, the key gears, and all, and reassemble.

Note that the one which was crashed with the parting operation might have the jaws or the ways in which they run distorted.

BTW -- when parting off something longer than its diameter, or farther from the chuck than its diameter, mount a steady rest on the other side of the carriage and support it with that, so it is less likely to catch and damage the chuck. (Don't use a live center in the tailstock, as it will pinch the parting tool when you get close to breaking through -- though I have done this, and relaxed it as I got down to about 1/4" diameter left. Relax it just enough so the center is no longer pushing on the workpiece, but keep it in the center hole to keep the end from whipping.

BTW If the chucks you have are not all the same brand, there is little chance that the parts will interchange, and the jaws are usually serial numbered to match the chuck, because they are fitted to the chuck at the factory. (At least in good chucks. :-)

Good Luck, DoN.

the late. One I made my self when I was parting off a piece of 3" aluminum rod and the rod pulled out and crashed the lathe.

want to sacrifice the good chuck

good chuck out of thee bad chucks.

Most of them come apart from the spindle side. Not all..but most

Gunner

The methodology of the left has always been:

1. Lie
2. Repeat the lie as many times as possible
3. Have as many people repeat the lie as often as possible
4. Eventually, the uninformed believe the lie
5. The lie will then be made into some form oflaw
6. Then everyone must conform to the lie

Is this an ordinary manual chuck? All the Kitagawa chucks I've run across were big $ hydraulic chucks on CNC lathes.

10" CNC hydraulically actuated chuck. No scroll, it has wedges. It looks to me like the body is worn along with the master jaws. I got a chuck for less than I've seen replacemnt jaws sell for. IIRC it was just over $1300 I paid.

Remove 333 to reply. Randy

That's what I thought.

Good deal, the ones I've seen were all big bucks.