Spring Cut off Tool Follow Up

[Toolmaker51]

Cutting angle referred to, is form of front, not top rake. There's justifications to leave nub on either side.

Back Rake & Top Rake; figuratively are synonymous. 'Form' indicates a cutting edge creating a predetermined contour without particular movements of either axis, beside attaining depth. Single-point threading, fillets and radii, multiple steps, O-ring grooves, chamfering can all be labeled thus, part features being accomplished by 'forming tools'.