Sometimes the best knowledge is gained from the simplest of devises. Make a washer or make a bolt. Seems simple enough. Now make 2 just alike. With washers the challenge is consistent thickness. I made 2 pair, but only nailed the thickness on 1 pair. For the bolt exercise, the head thickness on the pair i made is off, but once the 1" socket size was dialed in: I was very pleased to be able to repeat that in mere minutes. Now for the slot. Well that is a different story for a different day.