Richard,
The Myford 1410 4-way toolpost (Myford called it a four tool turret) won't hold anything over 8mm at centre height. They will fit any 7-seriues lathe, but with that caveat.
To quote the original advertising -"It is designed for use with 5/16" square tools or cutter blanks".
My 4-way has one of the slots enlarged on the bottom side to take bigger tools, but these days I only use a QCTP as recommended by John for day to day. Sometimes if I have an old big tool I revert to the old "elephant's foot" toolholder.
The 4-way is an ideal tool for stabbing yourself in the back of the hand with the unused mounted tooling!
Phil
Edited By Robbo on 19/02/2015 20:30:17