It is poor policy, excepting in very rare instances, to buy a "cheap" article, as, especially in these days of commercial greed, the best is none too good.
Figs. 2,786 and 2,787.—Wheel and roller pipe cutters illustrating range. The illustrations show the comparative movements necessary with the two types of cutter to perform their function. The wheel cutter requiring only a small arc of movement will cut a pipe in an inaccessible place as shown, which with a roller cutter would be impossible. Accordingly, the wheel cutter is said to have a greater range than the roller cutter.
Perhaps next in importance to quality, at least in most cases, is range. This may be defined as scope of operation, effectiveness, or adaptability. The importance of range is perhaps most pronounced in the selection of tools, especially for plants remote from repair shops.
For instance, in selecting a pipe cutter, there are two general classes: wheel cutters, and roller cutters. A wheel cutter has three wheels and a roller cutter one wheel and two rollers, the object of the rollers being to keep the wheel perpendicular to the pipe in starting the cut and to reduce burning. It must be evident that in operation, a roller cutter requires sufficient room around the pipe to permit making a complete revolution of the cutter, whereas, with a wheel cutter, the work may be done by moving the cutter back and forth through a small arc, as illustrated in [figs. 2,786] and [2,787]. Thus a wheel cutter has a greater range than a roll cutter.
Range relates not only to ability to operate in inaccessible places but to the various operations that may be performed by one tool.
| Diameter. | Thick- ness. | Circumference. | Transverse areas. | |||||
| Nominal internal. | Actual external. | Actual internal. | External. | Internal. | External. | Internal. | Metal. | |
| Inches | Inches | Inches | Inches | Inches | Inches | Sq. ins. | Sq. ins. | Sq. ins. |
| ⅛ | .405 | .27 | .068 | 1.272 | .848 | .129 | .0573 | .0717 |
| ¼ | .54 | .364 | .088 | 1.696 | 1.144 | .229 | .1041 | .1249 |
| ⅜ | .675 | .494 | .091 | 2.121 | 1.552 | .358 | .1917 | .1663 |
| ½ | .84 | .623 | .109 | 2.639 | 1.957 | .554 | .3048 | .2492 |
| ¾ | 1.05 | .824 | .113 | 3.299 | 2.589 | .866 | .5333 | .3327 |
| 1 | 1.315 | 1.048 | .134 | 4.131 | 3.292 | 1.358 | .8626 | .4954 |
| 1¼ | 1.66 | 1.38 | .14 | 5.215 | 4.335 | 2.164 | 1.496 | .668 |
| 1½ | 1.9 | 1.611 | .145 | 5.969 | 5.061 | 2.835 | 2.038 | .797 |
| 2 | 2.375 | 2.067 | .154 | 7.461 | 6.494 | 4.43 | 3.356 | 1.074 |
| 2½ | 2.875 | 2.468 | .204 | 9.032 | 7.753 | 6.492 | 4.784 | 1.708 |
| 3 | 3.5 | 3.067 | .217 | 10.996 | 9.636 | 9.621 | 7.388 | 2.243 |
| 3½ | 4. | 3.548 | .226 | 12.566 | 11.146 | 12.566 | 9.887 | 2.679 |
| 4 | 4.5 | 4.026 | .237 | 14.137 | 12.648 | 15.904 | 12.73 | 3.174 |
| 4½ | 5. | 4.508 | .246 | 15.708 | 14.162 | 19.635 | 15.961 | 3.674 |
| 5 | 5.563 | 5.045 | .259 | 17.477 | 15.849 | 24.306 | 19.99 | 4.316 |
| 6 | 6.625 | 6.065 | .28 | 20.813 | 19.054 | 34.472 | 28.888 | 5.584 |
| 7 | 7.625 | 7.023 | .301 | 23.955 | 22.063 | 45.664 | 38.738 | 6.926 |
| 8 | 8.625 | 7.982 | .322 | 27.096 | 25.076 | 58.426 | 50.04 | 8.386 |
| 9 | 9.625 | 8.937 | .344 | 30.238 | 28.076 | 72.76 | 62.73 | 10.03 |
| 10 | 10.75 | 10.019 | .366 | 33.772 | 31.477 | 90.763 | 78.839 | 11.924 |
| 11 | 12. | 11.25 | .375 | 37.699 | 35.343 | 113.098 | 99.402 | 13.696 |
| 12 | 12.75 | 12. | .375 | 40.055 | 37.7 | 127.677 | 113.098 | 14.579 |
| Diam. | Length of pipe per square foot of | Length of pipe per containing one cubic foot. | Nominal weight per foot. | Number of threads per inch. | |
| Nominal internal. | External surface | Internal surface | |||
| Inches | Feet. | Feet. | Feet. | Pounds. | |
| ⅛ | 9.44 | 14.15 | 2513. | .241 | 27 |
| ¼ | 7.075 | 10.49 | 1383.3 | .42 | 18 |
| ⅜ | 5.657 | 7.73 | 751.2 | .559 | 18 |
| ½ | 4.547 | 6.13 | 472.4 | .837 | 14 |
| ¾ | 3.637 | 4.635 | 270. | 1.115 | 14 |
| 1 | 2.904 | 3.645 | 166.9 | 1.668 | 11½ |
| 1¼ | 2.301 | 2.768 | 96.25 | 2.244 | 11½ |
| 1½ | 2.01 | 2.371 | 70.66 | 2.678 | 11½ |
| 2 | 1.608 | 1.848 | 42.91 | 3.609 | 11½ |
| 2½ | 1.328 | 1.547 | 30.1 | 5.739 | 8 |
| 3 | 1.091 | 1.245 | 19.5 | 7.536 | 8 |
| 3½ | .955 | 1.077 | 14.57 | 9.001 | 8 |
| 4 | .849 | .949 | 11.31 | 10.665 | 8 |
| 4½ | .764 | .848 | 9.02 | 12.34 | 8 |
| 5 | .687 | .757 | 7.2 | 14.502 | 8 |
| 6 | .577 | .63 | 4.98 | 18.762 | 8 |
| 7 | .501 | .544 | 3.72 | 23.271 | 8 |
| 8 | .443 | .478 | 2.88 | 28.177 | 8 |
| 9 | .397 | .427 | 2.29 | 33.701 | 8 |
| 10 | .355 | .382 | 1.82 | 40.065 | 8 |
| 11 | .318 | .339 | 1.450 | 45.95 | 8 |
| 12 | .299 | .319 | 1.27 | 48.985 | 8 |
Open construction should be employed, wherever possible, so that all parts of a machine that require attention, or that may become deranged in operation, may be accessible for adjustment or repair.