The next step would be to turn out a bore and fit a mandrel into it.
On the inner end of the mandrel put a block (F) of hard wood.
The discs are made by pouring lead round the screw-nose of the mandrel.
The disc is, of course, mounted on the mandrel, and the work on the slide-rest.
The shell to form the central chamber is attached to a mandrel, and the metal forced into a mould around it.
Claim—Constructing shells for firearms by forcing the metal into a mould around an internal shell supported on a mandrel.
This mandrel has now on it the cylinder, which is to be taken off.
The point of the mandrel was driven through a piece of block tin, about 1/2 in.
The second way is to weld a collar and shape this on a mandrel.
In this case, the casting would also be held by pressing a mandrel through the hub; as shown.