01-27-2020, 08:56 AM
If you knurl normally, ie, from the front of the toolpost, you want your tool with a RH shank - that is, the mounting shank is on the RIGHT when you view it from an operator's viewpoint. For access to work close to the headstock, the knurls are mounted on the left outside of the tool.
If you knurl abnormally, ie, from a toolpost mounted behind the work, you want a tool with a LH shank (a complete mirror of the normal RH tool). For access to work close to the headstock, the knurls are mounted on the right outside of the tool.
The center is a generalized compromise, with the knurls close to the center of the holder.
The round seems to just be a round mounting shaft that extends perpendicular to the knurl holders (parallel to the work) instead of a square shank that is perpendicular to the work.
If you knurl abnormally, ie, from a toolpost mounted behind the work, you want a tool with a LH shank (a complete mirror of the normal RH tool). For access to work close to the headstock, the knurls are mounted on the right outside of the tool.
The center is a generalized compromise, with the knurls close to the center of the holder.
The round seems to just be a round mounting shaft that extends perpendicular to the knurl holders (parallel to the work) instead of a square shank that is perpendicular to the work.