Sphere-Turning Lathe Attachment
In 1946, a friend described a ball-turning device his machinist had made to fit an Atlas lathe. Unfortunately, I never got a chance to look at it. I’ve tried to design and make an attachment ever since, and recently I succeeded. Although the machinist had made the fixture entirely of metal, I used wood for the fixture’s core and reinforced it on the sides with sheet brass.
The fixture bolts to the lathe’s bed and holds a gouge at a height that’s on line with the lathe’s centers. Then, with the lathe running, the fixture is pivoted to make the final cleanup passes on a previously roughed-out ball. The final diameter of the sphere is determined by the projection of the gouge’s tip from the block.
To make the fixture, I bandsawed the wooden core from an old bridge beam and machined the top and…