#4-40 Standoffs

#4-40 hex standoffs for circuit board and panel mounting, in brass and nylon 6/6. Lengths from 6, 10 and 15 mm, male-female and female-female.

#4-40 in numbers

Length is the body length measured across the hex. On a male-female standoff the stud is additional and stated separately on each listing — it is not included in the quoted length.

Choosing the material

Nylon 6/6 isolates: no ground path, nothing to short a nearby trace, but it creeps under sustained load and strips at a fraction of the torque metal takes. Brass conducts and can carry the board's ground to the chassis deliberately. Stainless is the structural choice where the stack has to carry weight.

Thread warning

M3 is the closest metric size and will not fit. The diameters sit within a couple of tenths of a millimetre of each other, and the wrong screw will start, bind after a turn, and strip the standoff rather than itself. Check the pitch before you assemble.