Chapter XLIV: =hardening and Tempering.=

=Purposes= 460
To resist wear 460
To increase elasticity 460
To provide a cutting edge 460
=Manufacturer's Temper= 460
=Blacksmith's Temper= 460
=Color Tempering= 460
=Practical Processes= 461 to 464
The muffle 461
Warping 461
Rapidity of reduction of temper 461
Brown and Sharpe's practice 461
Waltham Watch Co.'s practice 461
Pratt and Whitney Co.'s practice 461
Morse Twist Drill Co.'s practice 461
Outside hardening 462
Heating in fluxes 462
Monitor Sewing Machine Co.'s practice 462
Hardening saws 462
Drawing the temper 462
1. Lying in an open furnace 462
2. Stretched in a frame 462
3. Between dies 462
Stiffening saws 463
Tomlinson Carriage Spring Co.'s practice 463
Columbia Car Spring Co.'s practice 463
New Haven Clock Co.'s practice 464