The amount of carbon in various well-known tools and implements made of hardened steel is shown approximately by the following list:

.6 to .7 per cent.

.7 to .8 per cent.

.8 to .9 per cent.

.9 to 1.0 per cent.

Screw drivers.

Smiths' hammers.

Wrenches.

Machinists' hammers.

Anvil tools.

Punches for metals.

Circular saws.

Hand saws.

Gun barrels.

Hand picks.

Lathe centers.

Cold chisels.

Chisels for hot metals.

Wood augers.

Anvil facing.

Steel springs for Vehicles.

Vise jaws.

Drop-forgingdies.

1.1 to 1.2 per cent.

1.20 to 1.26 per cent.

1.26 to 1.30 per cent.

1.30 to 1.60 per cent.

Rock drills.

Pocket knives.

Ball bearings.

Saws for cutting steel.

Threading taps and dies.

Wood chisels.

Strong magnets.

Tools for cutting hard metals.

Hatchets, axes.

Files.

Lathe tools.

.

Twist drills.

Wire-drawing dies.

Metal scrapers.

Steel springs for power.

Pipe cutters.

Glass-cutters.

Milling cutters.

Cutters for woodworking machines.

Degree of Hardness.

Per cent of carbon.

Very hard...............................................

1.50

Hard................................

1.25

Medium hard.......................................

1.00

Tough...................................

.80

Tenacious..............................................

.65

Very elastic.............................................

.30