The corrugated back shaper heads are a very good alternative to the old style
shaper collars in many applications.
They are much less expensive and easier to use.
They are excellent for short run jobs where you need to make your own knives.
They are machined to accept 1/4" or 5/16" knifestock.
Corrugated back knives - 20 degree hook - 60 degree corrugations