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IE_18-Gravel
8-Gravel
Feb 13, 2026 12:10 PM UTC
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Novice Question - ‘total load at point’ Hex Driver

Hello All,

 

I’m trying to simulate torque applied to a ¼” hexagonal driver to a reduced A/F set screw. I have set the simulation up but getting very high stresses in the results.

 

My question is does applying the ‘total load at point’ effectively divide the moment load by 6 in this case, the point created is at the centre of the hex? Due to the stress reported I suspect I may have to divide the torque value by 6 manually when setting the load up?

skunks
skunksAnswer
19-Tanzanite
Feb 16, 2026 2:44 PM UTC

Here is a testpart1.

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8 replies

KenFarley
KenFarley21-Topaz II
21-Topaz II
Feb 13, 2026 2:12 PM UTC

If it was me and I were trying to represent the reality of the situation, a point load is not what I'd use to represent things. I'd start with:

(1) Make a model of a hexagonal bar, the end of the allen wrench.

(2) Assemble this hex in the head of the screw in your analysis assembly.

(3) Apply a torque or moment load to the "wrench". If it's easier, when modeling the wrench, model a blend to a cylindrical shape at the end so you can apply the moment to the cylindrical surface.

 

You might have to look at the contact definitions for the wrench, otherwise it will be assumed that it is perfectly bonded to the interfacing  surfaces, etc.

 

I haven't done this, so don't know if it's the best approach, but maybe someone with much more experience will have better suggestions.

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IE_18-GravelAuthor
8-Gravel
Feb 13, 2026 2:29 PM UTC

Thanks for the reply.

I modelled the hex 1/4" then with a reduced hex to represent the socket A/F.

I did all the analysis within a single part.

I created two volume regions at either end to represent the constraint and load areas.

I fully constrained the contact region (socket screw end) in all degrees of freedom, then applied the load in terms on Nm torque to the contact region (driver end) then added a centre point for the torque moment to act around.

But as mentioned the stress is very high so unlikely to be representative.

 

In CREO simulate I am very new to this and haven't touched FEA in over 25 years, was pro mechanica back then. So I'm not sure I'd be able to action your approach just yet. 

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skunks
skunks19-Tanzanite
19-Tanzanite
Feb 16, 2026 7:42 AM UTC

Please upload the STP data.

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