Actually, it is meant to help keep an edge longer and it works. You are
quite correct that it is a lubricant. Helping chips slide off instead of
adhering or trying to adhere results in lower local heating and abrasion,
making the edge last longer. The difference is quite apparent when machining
high strength stainless, titanium, inconel or other tough machining metals.
No difference for wood however.
"Steve Knight" wrote in message
...

the TiN coating is only a lubricant. it is put on the tools to help the
ejection
of metal chips. it is not meant to make the tool keep an edge longer. it
does
not really work with wood either. so they are a waste of money.
the right drill bit will drill materials faster then the wrong one. for
woodworking drill bits with deep flutes will eject wood chips better.
but the shape and design of the bit will make the performance difference
not the
coating.

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