OK, you might want to read this article: https://healthyhandyman.com/cobalt-v...rill_bits_pros
Basically you have bare naked high speed steel (HSS) drill bits. Then you have titanium nitride (TiN) bits and cobalt bits. Which is misleading because one describes the coating and one describes the alloy.
Cobalt bits are basically high speed steel but with 5-8% cobalt added which makes a stronger and harder alloy of steel.
TiN bits are HSS but with a coating of titanium nitride, a gold-looking color. The coating is low friction, lower than HSS by itself, so the bit does not heat up on the sides and cutting surface so much - heat is the enemy of HSS because it destroys the temper of the steel.
Unfortunately when you sharpen the TiN bits then you remove the coating and it loses effectiveness, at least on the cutting point, although the sides are still coated (but can wear off over time).
Cobalt bits are not a coating, the cobalt goes though the bit and it can be effectively sharpened and still retain the characteristics that the cobalt bestows.
Basically you have bare naked high speed steel (HSS) drill bits. Then you have titanium nitride (TiN) bits and cobalt bits. Which is misleading because one describes the coating and one describes the alloy.
Cobalt bits are basically high speed steel but with 5-8% cobalt added which makes a stronger and harder alloy of steel.
TiN bits are HSS but with a coating of titanium nitride, a gold-looking color. The coating is low friction, lower than HSS by itself, so the bit does not heat up on the sides and cutting surface so much - heat is the enemy of HSS because it destroys the temper of the steel.
Unfortunately when you sharpen the TiN bits then you remove the coating and it loses effectiveness, at least on the cutting point, although the sides are still coated (but can wear off over time).
Cobalt bits are not a coating, the cobalt goes though the bit and it can be effectively sharpened and still retain the characteristics that the cobalt bestows.
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