Dave explained on 20/12/2009 :
They did demonstrate what would happen with this drill, compared to a carbide
tipped drill, by pushing it tip first into a normal carbide grinding wheel.
Their drill formed a groove in the wheel, the carbide tipped drill had its
tip ground back.

Dunno if they are actually any good, but....

Any form of carbide will make a groove in a normal (gray or white)
grinding wheel. A green wheel is needed to sharpen carbide.

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