Plastic Wrench adapter for Torque up to 15 Nm

[ili_matic]

I am trying to solve an issue of torque wrench force marks on a thin hex head.
Background: The metal is ASTM A564 grade 630 (17-4)COND H1025. This thin hex is heated during shrink fit process.
During the next process these are torqued to 6 Nm in pots for lapping and then removed. Some slip from the wrench and even when they don't slip, we can see the contact area were the force was applied from the wrench.
Question: Is there a plastic that could be used to machine the size wrench/socket we need that would stand continuous use under forces up to 15 NM? Is there a brand available already available? We are capable of machining it as well as long as the plastic was easily machinable.
thank you

 

[3DDave]

I'm not sure how it would help. The load required to produce the torque is enough to damage the part. Changing the material suggests that either it will also do the same damage or that it will not be able to produce the torque.

Perhaps a different manner of trapping them is possible. For example, changing the fixture so that another fastener can be used to clamp the threads of this one.

Or make the hex over size and machine the finished hex after lapping, say by EDM.