The following table is the results from torque testing three different size hexagon keys made from five different Stainless Steel alloys we commonly use.

HEX SIZE 316L 17-4PHINCONEL 718465420
1/16"5 IN. LBS10 IN. LBS12 IN. LBS14 IN. LBS15 IN. LBS
1/8"44 IN. LBS75 IN. LBS87 IN. LBS90 IN. LBS92 IN. LBS
1/4"373 IN. LBS570 IN. LBS618 IN. LBS735 IN. LBS776 IN. LBS

This test was conducted where the hexagon was machined onto a round bar and heat treated (excluding 316L). The hexagon was them clamped in a hydraulic chuck and radial torque applied and measured via Mark-10 brand torque tester.

This test is not a simulation of a real life situation and should only be used as a reference to better understand the characteristics of each alloy.

In reality, there will be a tolerance difference between our tools and your fasteners. This tolerance will reduce the torque ability as the loading of the torque will be distributed over the hexagon differently than our test environment. A looser fit will have less torque ability than a tighter fit.

Torque reading are peak torque: torque was applied until no increase in torque was registered. This resulted in the hexagon either twisting, sheering, or deforming completely.

316L - No heat treating. Non-Magnetic.

17-4PH - H900 condition. Magnetic.

420 - Vacuum heat treated to 54 HRC. Magnetic.

465 - H950 Condition. Magnetic

Inconel 718 - H1350 Condition. Non-Magnetic.