pic: Twisted Hex Shaft

[rahilm]

Originally Posted by Andrew Y.

gotcha 7075 was the number iw as looking for. Just to be nosey it wasnt 7075 -0 right?

T7351 Actually.

Originally Posted by Brandon Holley

Wow, that is quite a failure for a 1/2" 7075 shaft. Can you explain in a bit more detail the application this was in under failure?

It was on our arm. Basically we have 2 Banebot's gearboxes with chain running up to the arm. We have approx. 50 lb-ft of torque (don't worry, 1:4 chain reduction, only 6.25 lb-ft on each gearbox). We have chain on either side of the arm, and we decided to change the tensioning method to turnbuckles. Almost immediately as we raised the arm, the turnbuckle one side (the twisted side failed) while the other one held. The torque of the arm in addition to tension being held by the chain all released in one instant twisting the shaft, as the tension still held on the other side (on which the gearbox's rollpins sheared)