N. Thornton formulated on Tuesday :
Only thing I havent done with them is use them on hard concrete or
stone, and I wouldnt expect them to do so well with concrete. But,
some day I'll find out.

Anyone else have experience doing this?

If you meant drilling concrete or stone with an HSS bit, then not
deliberatly ;-)

If you mean sharpening them like that for use in steel, then yes. I
have in circumstances where I have not been able to get enough purchase
to get enough weight behind the drill, but sharpened like that the bits
do not last very long. There will also be a greater tendancy to shatter
as they break through.

If you need to drill holes in heavy material, the way to do it is by
drilling a small pilot hole first. The pilot drill will have a much
smaller face in contact with the material and (if sharped correctly)
cut faster than bits with unusual sharpening methods.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.org