08-09-2013, 05:12 PM
Hi Dave,
I dont think it *has* to be 1 degree, as long as the broach has enough clearance to prevent the cutting edge rubbing, iirc 7 - 10 degrees, and as long as there's some cutting edge rake (what I remember seeing is "dishing" the front face with a.small dremelloid grinding wheel, poss after hardening?)
Most homebrew ones seem to fit in the tailstock ram and have the bearing seats set at an angle to the Morse taper and offset slightly to get the cutting edges on centre, ok but means the bits need to be accurately made to the same lengths, if I get the necessary tuits I'll make.mine to go on the qctp, that'll allow easy adjustments to get the cutting face on centre and adjust the off-axis angle if required for different materials?
I dont think it *has* to be 1 degree, as long as the broach has enough clearance to prevent the cutting edge rubbing, iirc 7 - 10 degrees, and as long as there's some cutting edge rake (what I remember seeing is "dishing" the front face with a.small dremelloid grinding wheel, poss after hardening?)
Most homebrew ones seem to fit in the tailstock ram and have the bearing seats set at an angle to the Morse taper and offset slightly to get the cutting edges on centre, ok but means the bits need to be accurately made to the same lengths, if I get the necessary tuits I'll make.mine to go on the qctp, that'll allow easy adjustments to get the cutting face on centre and adjust the off-axis angle if required for different materials?
Rules are for the obedience of fools, and the guidance of wise men...
(Douglas Bader)
(Douglas Bader)