Chuck and threaded insert

[Chris Barnett]

If several chucks are used, is the threaded adapter left on the lathe spindle or installed somewhat permanently in the chuck? If the insert is left on the chuck, is there any reason not to apply fairly high torque to the setscrew holding the insert on the chuck? Seems it would be a good idea to do this.

[Cyril Griesbach]

Leave the insert in the chuck.

[Dick Latshaw]

I agree with Cyril.

[Jim Becker]

While insert designs vary with manufacturer, they are generally designed to stay on the chuck. On the OneWay chuck I use, for example, it's actually not trivial to remove them as the taper is very precise and 'sticky' and you need to move the setscrews to use them to jack the insert out of the chuck. So, in my mind, the ability to change the insert if you change lathe formats, thus preserving the investment, is a good thing, but in general, it's not a device to be able to "share" a chuck repeatedly (or conveniently) with more than one machine.

[Steve Schlumpf]

If several chucks are used, is the threaded adapter left on the lathe spindle or installed somewhat permanently in the chuck?

Chris - by the way you phrased your opening question I 'assume' that this is a hypothetical situation and you are just wondering how the chuck/adapter situation works. As the others have stated, once the adapter is installed into the chuck, it is intended to stay there. If you want to use that same chuck on a lathe with a different spindle size you can change out the adapter. Adapters come in all the major spindle sizes and provides the user a cheap means to transfer the chuck and all the jaws over for use on a new lathe.


If the insert is left on the chuck, is there any reason not to apply fairly high torque to the setscrew holding the insert on the chuck? Seems it would be a good idea to do this.

I use the Oneway Talon chuck and it is an extremely tight fit when you install the adapter. Once the adapter is fully seated it is screwed in place with 3 screws and is not going anywhere. I would use the word 'firm' as far as the amount of torque I applied. Last thing I would want to do is strip out or break one of those screws!

Hope this helps answer some of your questions.

[Ken Fitzgerald]

The fit on my SN2 is extremely tight too! I would buy anothe adapter and use it on the other chuck and leave it there.

[Chris Barnett]

The case is not hypothetical at all. Bought four chucks, two Supernova2 and two Titans, since (I heard but now think the information was erroneous) Teknatool was moving manufacturing to China. If I had waited, would need to wait additional time perhaps for them to work out the bugs in China's process. And was told several chuck were preferred so that chucked work could be removed from lathe to use lathe for other work, thus keeping the exact same centerline of the piece removed.

Before I installed the Nova inserts in the chucks, thought I had better ask. Thanks for your comments; I think now it would be a good idea to torque the insert and then perhaps drill a dimple in the chuck to accept the setscrew firmly, since this should be a final location. Don't know why they provide a little red insulator; I had tossed these thinking they were left over punchouts (from what I don't know but I did think about it). They were recovered. Might help if I read the instructions! But I still do not know why they are needed; use could affect need to dimple the chuck.

[Allen Neighbors]

Those little red "punchouts" are to put in the hole before the set screw goes in, to keep the set screw from damaging the threads. This makes it possible to change inserts later, if needed.
Mine have the little gizmos in, and I've never regretted it. I've changed inserts twice before in one of my chucks. Now I have a spindle adapter, so I don't have to do that anymore. Works for me. :)