for my classes final we were given a 1.500" diameter 4.300" long piece of 12L14 and had to do some machining on it. The back side was just a step shaft with a hole drilled in the end and the opposite side had a 3/4" 16 thread, 30 degree shoulder, steps and thread relief groove. both sides had various minor chamfer's. one step had a tolerance of .002" nearly all other dimensions had a tolerance of .010" with a few of the chamfers having a larger tolerance. We were only allowed to use HSS tooling, and used a 4 jaw chuck. We were given a time limit of one and a half hours to complete. no one in my class got further than about half way through it, but my instructor said that he was able to finish the same project in half an hour. Are we all sub par machinist's? I feel like I could finish it in about two and a half hours, I think I spent around 15- 20 minutes just re-chucking the part trying to keep everything coaxial with in a thousandth. How long should an operation like that take a professional machinist? I feel like I just fell flat on my face, looking for some perspective.
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