American National 60° threads, 51 leaves 4-84 TPI (teeth per inch)
Starrett screw pitch gages are among the most useful tools in any toolbox.
They quickly determine the pitch of various threads.
These gages consist of a substantial steel case with a number of folding leaves at both ends,
each leaf having teeth corresponding to a definite pitch, marked on each leaf.
Starrett screw pitch gages are available in a wide range of sizes with different numbers of leaves in various
pitch ranges with which to gage.
English and metric threads are similar in form, but English threads are described in threads per inch
and metric threads by the distance from one crest to the next.
Starrett 156 and 472 screw pitch gages feature a locking device at both ends of the case,
so leaves can be securely locked in position for use.
Leaves on all gages have a special narrow design, permitting checking internal threads in nuts, etc., as well as external threads.
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