Finally got around to using my micrometer. Different setup than planned - putting in cams/valvetrain upgrades and staying naturally aspirated on my Mustang build. Plenty of usable street power. I sold the ATI with a blower setup and picked up an Innovators West. The interesting thing is ATI says they make their bores purposely a little small to spec because otherwise you can't get the right fit on a slightly small of spec crankshaft snout. From what I see Innovators West makes there unit exactly to spec. Nice thing as I was blown away with how precise a reading I got on the crank. I must fully acknowledge that I am not a machinist. BUT. I measured twice reaching down not looking at the reading and came back this exact to spec 1.2500 each time. On that dial, 24 to 0(25) and 0 to 1 is one thousandth. Supposedly we're trying to be within about a 3 TEN-thousandth range. I'd say I can probably call the reading between those thousandth marks in about 20 gradations by my eye... e.g. maybe as granular as half a ten-thousandth. And the reading each time was clearly well within a ten-thousandth of spec. I would have though just pulling the balancer off the snout dry would have removed some material. A sheet of copy paper is approx. 4 thousandths. So getting precision to at least as small as one ten-thousandth is 1/40th the thickness of a sheet of copy paper. It was about 55 degrees in my garage.. but both the crank and the micrometer were colder... I think I had worked out that iron/steel would expand about half a ten-thousandth per 10 degrees F.
ATI / Aftermarket Damper Interference Install 2020 Mustang GT - 0.0001 precision micrometer
- Thread starter deanm11
- Start date
Your terminology is weird. Just say a "tenth", "three tenths" etc. "Five tenths" and "half a thou" are interchangeable IMO, like 6:30 and half past six
Any machinist will know what you're talking about and people who don't know won't be relevant to what you're trying to accomplish.
Any machinist will know what you're talking about and people who don't know won't be relevant to what you're trying to accomplish.
Adjust your micrometer with your gage blocks at the same temperature you are using them. Let them both "soak" in your garage for two hours, do the adjustment, then make your measurement and any error due to expansion from temperature will be too small to consider. Your micrometer should have come with a special (capstan) wrench to do the adjustment with.
Thank you for the tip on calibrating. I don't believe I received the wrench so alternatively I can just shift my measurement based on how it calibrates to the blocks. Thanks !
This is the reason first world countries use metric. If you can count to 10 you have it knocked.
Below is a picture of a typical micrometer set. As you can see, it comes with a wrench to adjust the barrel and a micrometer standard to calibrate it with. This one is less than $40 on Amazon. You can purchase the micrometer standards separately or just buy one gage block within the range of the micrometer.
The vernier lines on the top of the barrel are used to resolve the last digit. Look for which of the vernier lines is touching or closest to one of the 0.001 tick marks on the rotating part, and write that down as the 0.0001 digit of the reading.
And make sure your fingers are also at the same temperature as the micrometer.