Wasn't sure where to post this one. Anyway, I just had to replace the blade bolt and nut on my mower. It ran me about $12 to get exact replacement parts from the dealer. Out of curioisty stopped at hardware store and found same SIZE nut and bolt, BUT, different threads for about $4. So question is, do the type of threads or thread count matter and if so, why? The replacement parts had a higher thread count then the nut and bolt at hardware store. How important are the threads?