FASTENERS 1 Inch Bolts & Screws
REFERENCE CHART — DETERMINING THREAD LENGTHS INCH
There is a formula for calculating minimum length of threads on any given hex head cap screw. It is as follows: Minimum thread length equals twice the basic thread diameter plus .250 inches for screw lengths up to and including six inches and twice the basic thread diameter plus .500 inches for lengths over six inches. The chart to the left is also a useful tool for determining at which lengths a given diameter bolt changes from fully threaded to partially threaded, according to industry specifications.
LENGTH STANDARDS FOR FULL OR PARTIAL THREADS
Capscrew Diameter
1/4”
5/16”
3/8” 7/16”
1/2”
9/16”
Fully Threaded Max. Length*
1-1/4 1-3/8 1-1/2 1-3/4 1-7/8 2-1/8
Capscrew Diameter
5/8”
3/4”
7/8”
1”
7/8”
1”
1
Fully Threaded Max. Length*
2-1/4 2-5/8 2-7/8 3-1/4 3-3/4 4
*These lengths and longer = partially threaded
REFERENCE CHART — INCH SIZE TO DECIMAL, THREAD PITCH
SIZE TO DECIMAL CONVERSION
STANDARD THREAD PITCH
Basic Major Dia. in.
Threads Per Inch (TPI) Coarse Thread UNC Fine Thread UNF
Threads Per Inch (TPI) Coarse Thread UNC Fine Thread UNF
Basic Major Dia. in.
Nominal Size in No.
Nominal Size in No.
Bolt Size No. or Inches
Bolt Size No. or Inches
D
D
0 1 2 3 4 5 6 8
80 72 64 56 48 44 40 36 32 28 28 24 24 20 20 18 18 16
7/8
9 8 7 7 6 6 5 4 4 4 4 4 4 4
14 12 12 12 12 12
0 1 2 3 4 5 6 8
0.0600 0.0730 0.0860 0.0990 0.1120 0.1250 0.1380 0.1640 0.1900 0.2160 0.2500 0.3125 0.3750 0.4375 0.5000
9/16 5/8 3/4 7/8 1 1-1/8 1-1/4 1-3/8 1-1/2
0.5625 0.6250 0.7500 0.8750 1.0000 1.1250 1.2500 1.3750 1.5000
64 56 48 40 40 32 32 24 24 20 18 16 14 13 12 11 10
1
1-1/8 1-1/4 1-3/8 1-1/2 1-3/4 2-1/4 2-1/2 2-3/4 2 3-1/4 3-1/2 3-3/4 3
4-1/2 4-1/2
10 12 1/4
10 12
5/16 3/8 7/16 1/2 9/16 5/8 3/4
1/4 5/16 3/8 7/16 1/2
4
BIT SELECTION CHARTS
PHILLIPS BITS
WOOD SCREW SIZE
MACHINE SCREW SIZE
SHEET METAL SCREW SIZE FLAT, OVAL, ROUND
BIT SIZE
FLAT, OVAL
ROUND TRUSS
ROUND FLAT, OVAL
SQUARE RECESS BITS
0 0, 1
0, 1
0, 1
0, 1
0, 1
0, 1
TAPPING/ SHEET METAL SCREW SIZE
WOOD SCREW SIZE
MACHINE SCREW SIZE
BIT SIZE
1 2, 3, 4
2, 3, 4
2, 3, 4
2, 3, 4
2, 3, 4, 5
2, 3, 4
2 5, 6, 7, 8, 9 5, 6, 7, 8, 9, 10 5, 6, 7, 8, 10 5, 6, 7, 8, 10 6, 8, 10
5, 6, 7, 8, 10
#0 #3, #4
#3, #4
#3, #4
3 10, 12, 14, 16 12, 14, 16
12, 14
12, 1/4, 5/16 12, 1/4
12, 14
#1 #5, #6, #7
#5, #6, #7
#5, #6, #7
5/16, 3/8, 7/16, 1/2
5/16, 3/8, 7/16, 1/2
4 18, 20, 24 18, 20, 24
3/8, 7/16, 1/2
#2 #8, #10
#8, #9, #10
#8, #10
#3 #12, #14
#12, #14
#12, #14
HEX KEYS/BITS
SOCKET HEAD SCREW SIZE
SET SCREW SIZE
BUTTON HEAD SIZE
FLAT HEAD SIZE
SHOULDER SCREWS
PRESSURE PLUGS
POINT SIZE
.050 1/16 5/64 3/32 7/64 9/64 5/32 3/16 7/32 1/8
#0 #1
#1, #2 #3, #4
#1, #2 #3, #4 #5, #6
#1, #2 #3, #4 #5, #6
- - - - -
- - - - - - -
TORX KEYS/BITS
#2, #3 #4, #5
#8
#10
#8
#8
BIT SIZE
Socket Set Screw
Socket Cap Screw
Flat Head Screw
#6
-
-
-
-
1/4
#10
#10
1/4
T3 T4 T5 T6 T7 T8 T9
#2
- - - - - - -
- - -
#8
-
-
-
-
#10 1/4
5/16
1/4
1/4
5/16
1/16
-
3/8
5/16
5/16
3/8
1/8
#3 #4
-
7/16
3/8
3/8
-
-
#2 #3 #4 #5 #6 #8
1/4
5/16
1/2 5/8
-
7/16
1/2
1/4 3/8 1/2
5/16
3/8
1/2 5/8
1/2, 9/16 5/8
#5, #6
3/8
7/16, 1/2 3/4
5/8
3/4
#8
METRIC
-
T10 #10, #12
#4, #5
SOCKET HEAD SCREW SIZE
SET SCREW SIZE
BUTTON HEAD SIZE
FLAT HEAD SIZE
SHOULDER SCREWS
POINT SIZE
T15 -
#6
T20 1/4
-
#10 #12 1/4
M2
M2.3, M2.5
M4 M5 M6 M8
M3 M4 M5 M6 M8
M3 M4 M5 M6 M8
- -
T25 -
#8
M2.5
M3 M4 M5 M6 M8
T27 5/16 T30 3/8 T40 7/16 T45 1/2
#10, #12
M3 M4 M5 M6 M8
M6 M8
1/4
-
-
5/16, 3/8
M10
M10 M12 M16
5/16
-
M12, M14
M10 M12
M10 M12
T50 - T55 -
3/8
7/16
M10
M16
7/16, 1/2
1/2
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