The guy was a wanker for sure but wow it's not hard to take a step back and simply refuse to engage with a guy like that. Just provide him warranty service, no more no less... Rather than being a twit about it and then rescinding the offer. Using an open truss design like that for a crank is ridiculously stupid anyway. It's objectively bad engineering, the section is unable to deal with torsion efficiently and the stress concentrations will be hell for fatigue. I'm guessing they saw some cool-looking "generative design" products (which is a very bad place to...