The document defines a spanner and wrench as a hand tool used to provide grip and torque for turning nuts and bolts. It then provides formulas to convert between bolt sizes in millimeters and the required spanner or wrench size based on ANSI/ISO standards. A second table shows formulas for converting bolt sizes to the appropriate Allen key size. The purpose is to help determine the proper tool size needed based on the bolt diameter.

1. Presentation By
Rahmat Ullah
B. Tech. (E.I.E)

2. Definition
Bolt Size to Spanner Size Conversion
Bolt Size to Allen Key Size Conversion

3. Spanner (Wrench):
 A wrench or spanner is a tool used to provide grip
and mechanical advantage in applying torque to
turn objects
◦ usually rotary fasteners, such as nuts and bolts
◦ or keep them from turning.
 A steel hand tool with a handle carrying jaws or a
hole of particular shape designed to grip a nut or
bolt head.

4. Bolt Size (mm) Formula
Spanner Size (mm)
ANSI/ISO
M3 B.S * 1.5 + 0.5 5
M5 B.S * 1.5 + 0.5 8
M7 B.S * 1.5 + 0.5 11
M4 B.S * 1.5 + 1 7
M6 B.S * 1.5 + 1 10
M8 B.S * 1.5 + 1 13
M10 B.S * 1.5 + 2 17
M12 B.S * 1.5 + 1 19
M14 B.S * 1.5 + 1 22
M16 B.S * 1.5 24
M18 B.S * 1.5 27
M20 B.S * 1.5 30

5. Bolt Size (mm) Formula
Allen Key Size (mm)
ANSI/ISO
M2 B.S - 0.5 1.5
M3 B.S - 0.5 2.5
M4 B.S - 1 3
M5 B.S - 1 4
M6 B.S - 1 5
M8 B.S - 2 6
M10 B.S - 2 8
M12 B.S - 2 10
M14 B.S - 2 12
M16 B.S - 2 14
Bolt Size to Allen Key Size Conversion

6. Feedback to improve…
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