after watching more video I believe that type tool is awkward to use so maybe thats a non runner!I think my next project will be a ball turner for my harrison 140, im not keen on the type using a boring head for some reason, have any of you got any different type designs? im leaning towards the double yoke design like tubalcain uses on youtube.
The other popular design, the one in Mr Kram's suggested video originates from a guy called Steve Bedair, so if you Google 'bedair ball turner', you can see what is there (fully dimensioned pdfs are on his site, but for a smaller lathe than a 140).
...only slight error he made was to some how get the tool the wrong way round so it made a sort of inside out ball shape...