Your missing the point. Everyone isn't an expert. THEY know their product better than any layman ever could. Why would they #1 not mention it in their video and definitely in the phone conversation? I know keys can and should fit snuggly. If I were giving someone guidance over the phone I would mention this. They already messed up by poor quality control with the hole not tapped deep enough. Who's to say they didn't "fix" the problem and tell him it was his error. Not seeing the method used to cut the keyway it's possible that the finish pass wasn't made and it was undersized. This has to be a small key. Something in the 1/8" to 3/16" range. If it's cut with an end mill it wouldn't be cut in one pass. To much deflection. They've lost credibility here. They should do the right thing and ship it back. Other wise he should request a refund. Grizzly sells a replacement insert head so he has options.