with a Radford pattern tool
This ball turning tool is based on the design
by J A Radford, published in Model Engineer issue 3354 of 4th October 1968.
This tool and its use are also very helpfully discussed by George Thomas in his book
The Model Engineers Workshop Manual.
Minor modifications I made include a gib for adjusting the dovetail slide, a coned spindle nose, bronze spindle bearings, and a band brake for friction. I fitted a round tool-holder using Loctite, instead of the square one screwed and silver soldered in place. Radford made the ends of the head flat, while GHT made his with flat sides. I made mine round, and radiused the ends of the slide to improve chuck clearance a bit. Instead of screwing the feed nut into the head, I simply used a cylindrical spigot and allowed it to float.
Drawings and materials for this tool (yet another version, with a square head this time) are available from Hemingway Kits (with which I have no connection).
Click the pics for enlarged views