Form tool

Claim 1

A FORM TOOL HAVING A TOOL HOLDER, A BIT STACK CARRIED BY AND REMOVABLY FASTENED TO SAID HOLDER, SAID BIT STACK COMPRISING A STACK OF AT LEAST TWO SUPERIMPOSED INDIVIDUAL CUTTING BITS OF IDENTICAL SIZE AND SHAPE IN PLAN AND HAVING CORRESPONDING CUTTING SIDES ARRANGED FLUSH WITH EACH OTHER, THE CUTTING SIDES OF SAID BITS HAVING IDENTICAL CUTTING EDGES AND THE CUTTING EDGE OF THE TOPMOST BIT ONLY ADAPTED TO ACT ON A WORKPIECE AT ANY ONE TIME, EACH LOWER BIT IN THE STACK SUPPORTING AND REINFORCING THE BIT IMMEDIATELY THEREABOVE IN THE STACK AND THE CUTTING EDGE OF EACH SUCH LOWER BIT BEING PROTECTED WHILE THE TOOL IS IN USE BY THE BIT IMMEDIATELY THEREABOVE AND BY THE FLUSH ARRANGEMENT OF SAID CUTTING SIDES, SAID BITS BEING SELECTIVELY AND INDIVIDUALLY REMOVABLE FROM THE STACK AND ALSO BEING INTERCHANGEABLE IN THE STACK WHEREBY ANY OF SAID BITS CAN BE SELECTIVELY POSITIONED AT THE TOP OF THE STACK WITH ITS CUTTING EDGE DISPOSED FOR OPERATIVE ENGAGEMENT WITH THE WORKPIECE, MEANS ASSOCIATED WITH SAID HOLDER OVERLYING SAID TOPMOST BIT AND PROVIDING A LOCATING SURFACE ENGAGED BY SAID TOPMOST BIT, AND MEANS FOR ANGULARLY ADJUSTING SAID OVERLYING MEANS ABOUT AN AXIS COINCIDENT WITH THE CUTTING EDGE OF SAID TOPMOST BIT TO VARY THE RAKE ANGLE OF SAID BIT STACK.