The m3 and m4 nominal screw sizes have two drilled holes spaced 180 degrees apart.
Allen key sizes for metric screws.
Their purpose is largely to serve specialized applications where size constraints and strength requirements need to be met.
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.
Nominal screw sizes m5 and larger have six drilled holes spaced 60 degrees apart unless the purchaser specifies two drilled holes.
Hold on to it or post it somewhere in the garage where you can hold up the key or socket screw head to the physical picture this can help you to determine which size of allen wrench you need or have on hand.
Refer the following table for metric allen key sizes and dimensions for corresponding socket head cap screw based on iso 4762 din 912 standards.
Hex key and torn key sets provide multiple head sizes so they can be used with a range of fasteners.
While these metric allen key sizes do exist they rarely appear in your basic allen wrench sets.
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.
Non sparking non magnetic allen wrenches can be useful in hazardous environments.
Less common metric sizes.
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.
In the united states larger metric half sizes like 6 5 mm aren t standard in most hex key sets.
These sizes are 1 mm 1 25 mm 3 5 mm 4 5 mm 5 5 mm 7 mm.
Screw diameter drive size.
Here we have given the tool size only for metric thread bolts.
Substituting uncommon hex sizes.
Socket flat socket button socket cap set screw 1 6mm.
Lastly there s one other added benefit to having both sae metric hex keys.
We have given a table for your easy selection of proper size of tools.
Drilled head metric hexagon socket head cap screws normally are not available in screw sizes smaller than m3 nor larger than m36.
A hex key allen wrench or allen key is a simple tool used to drive bolts and screws with hexagonal sockets in their heads.
However the 1 4 sae hex wrench will likely work in place of a 6 5 mm wrench.