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Threading

basic_thread_shapes.jpg (36450 bytes)

Basic thread shapes

parts_of_a_thread.jpg (27498 bytes)

Parts of a thread

reading_thread_designations.jpg (66388 bytes)

Reading thread designations

three_wire_method.jpg (55913 bytes)

Three-wire method of measuring threads based on pitch diameters

thread_gage_1.jpg (14698 bytes)
thread_gage_2.jpg (18868 bytes)

When cutting U.S. Standard Threads, set the compound at exactly 29º,
adjust the chasing tool on center and to conform to position with the
60º center gage. Move the tool in to just touch the work. Re-check setup.
 Feed the tool in by moving only the compound. By using the compound,
there is less stress on the tool bit and the cut is cleaner.

Threads/inch

Depth @ 29º

Threads/inch

Depth @ 29º
2 .3713 18 .0412
4 .1856 20 .0371
5 .1485 24 .0310
6 .1237 27 .0275
7 .1060 28 .0265
8 .0928 30 .0247
9 .0825 32 .0232
10 .0742 36 .0206
11 .0675 40 .0186
12 .0620 48 .0155
13 .0570 50 .0148
14 .0530 64 .0116
16 .0464 72 .0103

Also refer to the Hand-tapping Section.