Single Bid Ball Turning Attachment for Lathes Radius Turn Ball up to 38 mm Diameter - Amazon.com
Assorts' Radius Ball Turning Tool for Lathe 3/8" Shank with HSS Tool Bit | eBay
Small Ball and Radius Turning Tool - Designed to Cut Round Shapes or Curves in Brass, Aluminum, Steel, Wood or Plastic on your Bench Top Metal Lathe, LittleMachineShop.com (2569) - Amazon.com
Ball Turning
Lathe Ball Turning Attachment Build - YouTube
Sphere Turning
Assorts' Radius Ball Turning Tool for Lathe 3/8" Shank with HSS Tool Bit - Amazon.com