Allen Key Sizes For Metric Screws

Screw diameter drive size.

Allen key sizes for metric screws.

For example for an m8 socket head cap screw we need at least 32 8 head size 40mm clearance above the screw for easy accessibility. Metric tools for hex head bolts and socket heads diameter 1 4 5 16 3 8 7 16 1 2 9 16 5 8 3 4 7 8 1 1 8 1 1 4 1 3 8 1 1 2 1 3 4 wrench size 7 16 1 2 9 16 5 8 3 4 13 16 15 16 1 1 8 1 5 16 1 1 2 1 11 16 hex key size 3 16 1 4 5 16 3 8 3 8 7 16 diameter m16 mio m12 m14 m16 m18 m20 m22 m24 m30 wrench size 7 mm 8mm 10mm 13mm 17mm 19mm 22mm 24mm 27mm. Nominal screw sizes m5 and larger have six drilled holes spaced 60 degrees apart unless the purchaser specifies two drilled holes. Socket flat socket button socket cap set screw 1 6mm.

Their purpose is largely to serve specialized applications where size constraints and strength requirements need to be met. The tool is usually formed of a single piece of hexagonal rod of hard steel with blunt ends that are meant to fit snugly into the screw s socket bent in an l shape with unequal arms the tool is usually held and twisted by the long arm creating a large torque at the. However the 1 4 sae hex wrench will likely work in place of a 6 5 mm wrench. Substituting uncommon hex sizes.

The m3 and m4 nominal screw sizes have two drilled holes spaced 180 degrees apart. 2 we use allen key or hex key allen keys or hex keys two are same but name is different in different countries for allen bolts csk bolts button head bolts and grub screw set screw. These sizes are 1 mm 1 25 mm 3 5 mm 4 5 mm 5 5 mm 7 mm. Drilled head metric hexagon socket head cap screws normally are not available in screw sizes smaller than m3 nor larger than m36.

While these metric allen key sizes do exist they rarely appear in your basic allen wrench sets. Hex key and torn key sets provide multiple head sizes so they can be used with a range of fasteners. A hex key allen wrench or allen key is a simple tool used to drive bolts and screws with hexagonal sockets in their heads. An allen key size chart often comes with furniture you need to build on your own such as baby cribs outdoor swings or computer desks.

Refer the following table for metric allen key sizes and dimensions for corresponding socket head cap screw based on iso 4762 din 912 standards. Torx keys are used for fasteners having a head with a 6 point star or asterisk shaped socket and are frequently used in computers and electronics. Less common metric sizes. In the united states larger metric half sizes like 6 5 mm aren t standard in most hex key sets.

Lastly there s one other added benefit to having both sae metric hex keys. Non sparking non magnetic allen wrenches can be useful in hazardous environments.