Hollow Chisel Mortiser
I won't try to describe this better than Bob Van Dyke from the Connecticut Valley School of Woodworking and Fine Woodworking.
Bob authored this article with a nicely done video:
How to Sharpen Hollow Chisel Mortising Bits
One note though: These tools should not be re-shaped. If that is needed, the bit should be replaced.
About this site
Remember : The goal of sharpening is to produce sharp tools, and these tools can injure you if mishandled. Safety measures should be followed to protect yourself and those in your shop. Be sure to read and follow all instructions from the manufacturer, and and utilize proper safety equipment. Never consume alcohol or anything that could impair your judgement before sharpening tools, or using sharp tools.
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