LATHE OPERATIONS - OD1645 - LESSON 1/TASK 3
(4) Lead.
The distance a screw thread advances axially in one complete
revolution. On a single-thread screw, the lead is equal to the pitch. On a
double-thread screw, the lead is equal to twice the pitch, and on a triple-
thread screw, the lead is equal to three, times the pitch (figure 39).
FIGURE 39.
RELATION OF LINEAR PITCH FOR SCREW THREADS.
(5) Crest (also called "flat").
The top or the outer surface of the
thread joining the two sides.
(6) Root.
The bottom or inner surface joining the sides of two adjacent
threads.
(7) Side.
The side of a thread is the surface which connects the crest
and the root.
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