wrote

I have a large (3.5") Forstner bit that has lost its edge. Is there a
DIY way to sharpen it, or is this something that must be done by a
professional? It looks like I might be able to hone the teeth and the
knife edges, but I'd like to hear what you folks have to say about it
before I do.

I recall that some sixty-five years ago, ie before diamond tools and
suchlike, my revered woodwork teacher told me (with some satisfaction) how
he had managed to sharpen the peripheral edge with a triangular engineer's
scraper.

I've never tried it, but I imagine it would get into the corners more easily
than the rotary and other tools.

Jeff

--
Jeff Gorman, West Yorkshire, UK
email : Username is amgron
ISP is clara.co.uk
www.amgron.clara.net