I have seen comments elsewhere that claim the crank tightening bolt is too soft for the recommended torque. Any experience with this? What is the recommended torque?
It was me talking about the bolt.
I've seen complaints about cranks unscrew themselves over time in Lexon crankset thread. Given that the construction of the BigRock cranks is pretty much the same and what I've received, they use the same bolt, which is made of some lightweight alloy.
Loss of tension is connected with material stretching and it is the early sign of the part not being up to spec which is also confirmed by some specialist in metal works whom I know personally. You made get away with it using locktite and being very gentle with the part bit given the size of the bolt and the specified torque, it's only a matter of time when it will snap.
I experienced rounding, cross-threading, loss of torque and snapping with cheap lightweight bolts and I don't think it's worth the risk, especially with cranksets where a malfunction may cause some serious incidents.