Useful Resources

Fastener Materials (Basic)

Washer Dimensions 

Thread Pitches Imperial / Metric 

 Material Strengths 

Blind Bolts 

Metric / Imperial Conversions 

Tapping & Hole Sizes 

Hank Bush Gauges 

 

Metric Socket Cap Screws

Thread Diameter Size Allen Key Wrench Size
M2
1.5
M2.5
2.0
M3
2.5
M4
3.0
M5
4.0
M6
5.0
M8
6.0
M10
8.0
M12
10.0
M14
12.0
M16
14.0
M20
17.0
M24
19.0
M30
22.0
M36
27.0
M42
32.0
M48
36.0
M56
41.0
M64
46.0

Metric Socket Set (Grub) Screws

Thread Diameter Size Allen Key Wrench Size
M2
0.9
M2.5
1.3
M3
1.5
M4
2.0
M5
2.5
M6
3.0
M8
4.0
M10
5.0
M12
6.0
M14
6.0
M16
8.0
M20
10.0
M24
12.0
M27
14.0
M30
14.0
M36
17.0

Metric Socket Button Screws

Thread Diameter Size Allen Key Wrench Size
M3
2.0
M4
2.5
M5
3.0
M6
4.0
M8
5.0
M10
6.0
M12
8.0
M14
8.0
M16
10.0
M20
12.0
M24
14.0

Metric Socket Button Screws

Thread Diameter Size Allen Key Wrench Size
M3
2.0
M4
2.5
M5
3.0
M6
4.0
M8
5.0
M10
6.0
M12
8.0
M14
8.0
M16
10.0
M20
12.0
M24
14.0

 

 

How to measure the thread

The pitch is the distance from the crest of one thread to the next in mm. TPI (Threads per inch) is used by inch thread

Standard

Otherwise known as UNC Unified National Coarse

standard threads (coarse thread)

UNC meaning Unified Coarse, is the most dominant used in the USA. Often used in the agricultural industry because of their strong coarse threads.  Generally available in steel and stainless steel.  Come in higher grades – high tensile and higher grades available.

Fine

Otherwise known as UNF Unified National Fine.

Imperial TPI's (Threads per inch)

The pitch is the distance from the crest of one thread to the next in mm. TPI (Threads per inch) is used by inch thread

 

SIZE UNC BSF UNF WHIT/BSW SIZE UNC BSF UNF WHIT/BSW
3/16”   32   24 1 1/8” 7 9 12 7
¼” 20 26 28 20 1 ¼” 7 9 12 7
5/16” 18 22 24 18 1 3/8” 6 8   6
3/8” 16 20 24 16 1 ½” 6 8 12 6
7/16” 14 18 20 14 1 ¾” 5 7   5
½” 13 16 20 12 2” 4 ½ 7   4 ½
9/16” 12 16 18 12 2 ¼” 4 ½ 6   4
5/8” 11 14 18 11 2 ½” 4 6   4
¾” 10 12 16 10 2 ¾” 4     3 ½
7/8” 9 11 14 9 3” 4     3 ½
1” 8 10 12 8          
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