View Full Version : are HSS bits heat treated?

11-04-2006, 11:42 AM
are HSS bits heat treated?

where can i learn more about them in detail, like their hardness and what treatment if any theyv undergone?

11-04-2006, 12:38 PM
I assume you mean lathe cutter bits, here?

Yes, they're heat-treated. The exact details depend on the alloy used
for the bits. Typically, they're heated to somewhere between 2200 and 2500F and then air cooled, tempered at somewhere between 1000 to 1300 depending on alloy and then ground to finish dimensions.

Machinery's Handbook has some brief discussions on this; each different alloy will have slightly different protocols for hardening for various types of service.

- Bart

11-04-2006, 04:59 PM
HSS stands for High Speed Steel. HSS is alloyed with tungsten. HSS retains hardness even when red hot becuase of the tungsten alloy. Most common tool steels would loose most of their hardness when heated to red hot temps but HSS keeps on going.

11-04-2006, 05:35 PM
Short answer: yes, they are heat treated. HSS requires very carefully controlled treatment cycles, however, that are far more demanding than the "heat to cherry red and quech in water" routine of plain carbon steel. I won't say it's impossible in a home shop, because as soon as I do somebody will come along who has done it, but "highly impractical" might cover it.