One of my first metalworking projects was making die holders for threading on the lathe. This project suited me very well at the time and provided the opportunity to gain experience using the lathe. I produced my own tooling for threading, one of the basic tasks of metalworking.
Two die holders are shown below. The holders accommodate dies of 20 and 25 mm diameter. The dies are the round, split, adjustable type, that are adjusted prior to insertion in the holder by means of a screw in the die. The outer surface of the die includes two "dimples" for securing them in the holder.
I was pleased with the performance of the first two die holders, and eventually made a set of seven, one for each of my dies.
A through-hole is included in the holder that has a diameter equal to the size of the maximum diameter of the die. One end of a rod fits into this hole while the other end is gripped by a chuck that is positioned in the lathe tailstock. It is recommended that the rod material be 12 mm diameter.
Threading is done manually. Do NOT power the lathe.
Threading is accomplished as shown in the below photos -
A die is installed in the holder which is mounted in the lathe.
A Manual Mandrel Handel (See Article Number 13.) is inserted in the bore of the lathe spindle (opposite the chuck) to provide for manual turning of the chuck and workpiece while threading.
The tailstock ram is used to bring the die into contact with the workpiece at the start of threading. Threading then progresses as the Manual Mandrel is turned manually, while the handle of the die holder is held steady.