Sometimes you require tailstock support while turning an object, but for whatever reason lack or can't use a center hole. A Jacobs #100 armature chuck works well for small work, but for something bigger you really need a small lathe chuck attached to a live center.
Bison makes a nice one but they tend to be rather expensive for a piece of tooling that is used very infrequently. How about a cheap 4 jaw chuck that just slips onto a live center?
This 80mm 4 jaw chuck was imported directly from Asia for about $60. It was gritty with grinding dust and sharp edges, but after a good going-over with a file and a thorough cleaning it should work well enough. With independent jaws accuracy shouldn't be a problem.
Here I'm turning the backplate for the chuck. The live center in the tail stock is a Royal with a CNC or extended point. It's a great center that will work well with this project.
Now the chuck backplate has been parted, flipped around and I'm now turning a internal taper to match the live center. The tiny Micro100 carbide boring bar worked great for this process.
And here you can see the live center fits well into the chuck backplate.
Transfer screws were used to mark the chuck mounting holes on the backplate.
The holes were drilled in the backplate for the cap screws.
And now you may be wondering, what in the world are the uses for such a tool? Here's one scenario:
This long piece of stock is too big to fit in the spindle and I wish to prep it for a steady rest. I don't like to run raw stock in the steady so I want to turn down an area of the stock so it runs smoother. There's many ways to do this, but here with the stock held in the 3 jaw it's a very quick operation to setup the 4 jaw at the tailstock and center it with the dial indicator.
A smooth area is lightly turned on the stock.
And now the work is ready to support via the steady rest for additional turning.
While a tail stock chuck isn't something you will use every day, it's a handy piece of tooling to have around and it wasn't a very expensive project.