Posted by BillS on February 10, 2007 at 15:01:17:
In Reply to: hobb sharpening posted by mike prida on February 09, 2007 at 14:48:51:
Sharpening, when done correctly, does not affect the profile, so does not affect accuracy or class. Class is a way to define the accuracy of the hob's specs, mainly profile and profile errors.
When done correctly means grinding the tool's face or gash flat and at the correct angle, and following the gash angle correctly if the gash is helical. If the tool's face is angled wrong, for instance, the rack form angle will be slightly modified, and it's generated gear involute will have a slight pressure angle error.