| Here 1.299 ÷ 8 = .162375. | |||||
| 1.000000 | |||||
| Then 1 - .162375 | .162375 | = | .8376. | ||
| .837635 | |||||
For the sharp V-thread the following rule is employed:
Rule.—Diameter-(1.73205 ÷ pitch) = diameter at root.
Example.—What is the diameter at the root of a sharp V-thread of 8 pitch, and measuring 1 inch diameter at the top of the thread?
| Here 1.73205 ÷ 8 = .21650. | |||||
| 1.0000 | |||||
| Then 1 - .2165 | .2165 | = | .7835. | ||
| .7835 | |||||
Fig. 1013.
For cutting square threads the class of tool shown in [Fig. 1013] is employed, being made wider at the cutting point c than at b or at d, so that the cutting may be done by the edge c, and the sides a may clear, which is necessary to reduce the length of cutting edge and prevent an undue pressure of cut from springing the work.