The fine standard tool is to the earlier standard, retaining a taper on the back of the flange to avoid the chances of accidentally cutting a step should the casting be postioned slightly more tightly on the mandrel than its predecessor.

The standard standard tool is to the earlier standard, retaining a taper on the back of the flange to avoid the chances of accidentally cutting a step should the casting be postioned slightly more tightly on the mandrel than its predecessor.
The dimensions of this tool match those of the 16 mm Narrow Gauge Association standard profile.