The best way to use an outside micrometer on something cyllindrical like your pistons is to (after zeroing it on a certified standard) set it to what you think the measurement should be and lock it at that setting (alternatively close the micrometer on the piston until the ratchet clicks then back it off about 5 tens and lock it). Then try to slip it around the piston. If the piston is larger than what you have the micrometer set at it won't go if it's smaller it will. It's easiest to work from the direction of having the micrometer set too big so in short what you are doing is getting the micrometer set just a little too big as your starting point. From there close it down one ten and lock it and try again repeating until it won't slide around the piston and then backing it off half a ten and locking it. If it slides over the piston then you have your measurement if not back it off another half ten. This method will give you the correct measurment including the guesstimate digit (the fraction of a ten)for scientific notation.
Quote:
Originally Posted by cdigerlando
In all likelyhood my machinist probably did a better job measuring all of this stuff than I did. Harry is a Nasioc member, and a pretty high level engineer in Central Florida. He has a lot of good measurement tools, but we engineers don't really use them that much. I trust a good practiced machinist for measurment better than myself.
I worked on a new technique to get around the piston and into the bores. Everything is looking pretty good. 3.816 on the pistons, about 3.8195 on the bores. I still want to check the bores with a bore caliper though so I can get top and bottom measurments.
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