----+-------++-----+-----+-------+------+------+
| | 1/64| 467 | 234 | 106 || | 1/32| 148 | 74.0 | 43.3 |
|3/32 | 1/32| 306 | 153 | 69.5 || 1/8 | 1/16| 104 | 51.8 | 32.0 |
| | 1/16| 200 | 100 | 45.5 || | 1/8 | 69.6 | 34.8 | 20.3 |
| | 3/32| 156 | 78 | 35.5 ++-----+-----+-------+------+------+
+-----+-----+------+------+-------++ | 1/64| 183 | 91.6 | 68.0 |
| | 1/64| 417 | 209 | 94.8 ||3/16 | 1/32| 135 | 67.5 | 39.4 |
| 1/8 | 1/32| 273 | 136 | 62.0 || | 1/16| 94 | 47.0 | 27.4 |
| | 1/16| 179 | 89.3| 40.6 || | 1/8 | 64.3 | 32.2 | 18.8 |
| | 3/32| 140 | 69.8| 31.7 ++-----+-----+-------+------+------+
+-----+-----+------+------+-------++ | 1/64| 171 | 85.7 | 50.1 |
| | 1/64| 362 | 181 | 82.2 || 1/4 | 1/32| 126 | 63.2 | 36.9 |
|3/16 | 1/32| 236 | 118 | 53.8 || | 1/16| 87.8 | 43.9 | 25.6 |
| | 1/16| 155 | 77.4| 35.2 || | 3/32| 70.4 | 35.2 | 20.6 |
+-----+-----+------+------+-------++-----+-----+-------+------+------+
| 1/4 | 1/64| 328 | 164 | 74.5 || 3/8 | 1/64| 156 | 77.8 | 45.4 |
| | 1/32| 215 | 107 | 48.8 || | 1/32| 116 | 57.8 | 33.8 |
+-----+-----+------+------+-------++ | 1/16| 79.7 | 39.9 | 23.3 |
| 3/8 | 1/64| 286 | 143 | 65.0 || | | | | |
+-----+-----+------+------+-------++-----+-----+-------+------+------+

[1] Cutting speeds for tools of a good grade of high-speed steel,
properly ground and heat-treated.--From MACHINERY'S HANDBOOK.

=Average Cutting Speeds for Turning.=--The cutting speed is governed
principally by the hardness of the metal to be turned; the kind of steel
of which the turning tool is made; the shape of the tool and its
heat-treatment; the feed and depth of cut; whether or not a cooling
lubricant is used on the tool; the power of the lathe and also its
construction; hence it is impossible to give any definite rule for
determining either the speed, feed, or depth of cut, because these must
be varied to suit existing conditions. A general idea of the speeds used
in ordinary machine shop practice may be obtained from the following
figures:

Ordinary machine steel is generally turned at a speed varying between 45
and 65 feet per minute. For ordinary gray cast iron, the speed usually
varies from 40 to 50 feet per minute; for annealed tool steel, from 25
to 35 feet per minute; for soft yellow brass, fr