For $625 a guy could get a small lathe from Grizzly and set it up specifically for threading ferrule tenons. Takes up very little space & can sit on a typical bench. I'd think the added strength of the tenon remaining a true 5/16", combined with cut threads rather than squeezed threads, the $625 is a cheap upgrade for anybody that actually takes their work seriously. Not trying to ruffle feathers, just sayin.