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TM 9-254
5-9.
Screw Thread - Continued
Table 5-11. Basic Coarse Thread Dimensions and Tap Drill Sizes - Continued
Commercial
Decimal
Nominal size
Outside
Pitch
Root
tap drill to
equivalent
diameter
diameter
diameter
produce approx
of tap
Inch Threads
(in.)
(in.)
(in.)
75 percent
drill
per inch
full thread
2 3/4-4
2.7500
2.5876
2.4252
2 1/2
2.5000
3-3 1/2
3.0000
2.8145
2.6288
2 23/32
2.7187
3 1/4-3 1/2
3.2500
3.0645
2.8788
2 31/32
2.9687
3 1/2-3 1/4
3.5000
3.3002
3.1003
3 3/16
3.1875
3 3/4-3
3.7500
3.5335
3.3170
3 7/16
3.4375
4-3
4.0000
3.7835
3.5670
3 11/16
3.6875
5-10.
Wire Gage.
a.
The size of wire may be designated either by gage number or by its diameter in mils. Usually the size of wire
less than one-half of a inch in diameter is stated in gage number. Wire larger than one-half of an inch in diameter usually
is described in terms of its diameter in mils (one-thousandth of an inch) or in terms of its cross-sectional area in circular
mils. The size (gage number) of a solid wire refers to the cross-section of the wire perpendicular to its length. The size or
gage number of a stranded wire refers to its total cross-section
b.
American Wire Gage is commonly used in the United States for copper and aluminum wire and in general for
wire used in electrical work. It is designated by the abbreviation AWG.
c.
Data on the relations of length, mass, and resistance of annealed copper wire in abbreviation AWG.
American Wire Gage sizes is listed in table 5-12.
Table 5-12. Annealed Copper Wire Data
Cross-section at 20°C
Ohms per 1000 feet
Gage
Diameter
no.
in mils
Circular
Square
0°C
20°C
75° C
(AWG)
at 20°C
mils
inches
(32° F)
(68° F)
(167° F)
0
324.8
105,500
.08289
.09055
.09827
.1195
2
257.6
66,370
.05213
.1440
.1563
.1900
4
204.3
41,740
.03278
.2289
.2485
.3022
6
162.0
26,250
.02062
.3640
.3951.
.4805
8
128.5
16,510
.01297
.5788
.6282
.7640
5-26
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