Have mercy on your lathe! Conventional, fixed axle tools set up almost unbearable strains on the spindle bearings of a light lathe. Moreover, the finished knurl produced in this way is seldom satisfactory.
Neither of the following designs create these strains; allowing the two knurls to 'float' on the work. Each employs two sturdy cheek plates which steady the arms enormously when traversing the work.
Each design accepts straight or diamond knurls which must be ordered separately and can quickly be changed from one pattern to the other.