1
$\begingroup$

I can't find an example calculation for the maximum torque of an allen key socket (the female bit on the screw head that the allen key goes into) anywhere online, or in textbooks, can someone point me in the right direction as it seems like it should be readily available.

From what I've found, max tightening torques are normally based on the preload requirements, not the failure of the head, but perhaps I am wrong on this. I know that I could measure the maximum torque for a screw and then scale the result for different materials/depths (assuming depth scales linearly?), but now I'm just curious what the calculation would look like. I tried estimating it assuming that you shear all the material away in a cylinder around the allen key socket but this does not give a good estimate, and also doesn't really make sense as with this method the torque for allen keys and torx is the same which is not the case.

Improve this question
$\endgroup$
2
  • $\begingroup$ Then don't estimate it on a fictitious cylinder, but on the actual contact area. $\endgroup$
    – Solar Mike
    Commented Jul 8 at 13:49
  • $\begingroup$ It only has to be greater than the the torque needed to wring a hex shaft Allen key. Grade ten will usually be fine if the socket depth is about the same as the distance across the flats. I've never walled out a grade 10 socket head, and I've taken a bunch of cranky old hydraulics apart. But I've certainly gone through a bucket full of Allen keys. $\endgroup$
    – Phil Sweet
    Commented Jul 8 at 20:02

0

Reset to default

Browse other questions tagged or ask your own question.