What’s the pitch diameter of .4375-20UNF-3A before plate (.001” ±.0001” thick per side)?
The last time we ran this job was 10 years ago; we couldn’t locate a set of ring gages specifically for this job, and I’m not 100% sure how to calculate p/p pitch diameter.
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P.D = .4019-.4050
(.0011” Max amount of plate per side) x 4 = .0044”
(.0009” Min amount of plate per side) x 4 = .0036”
.4050” - .0044” =
.4006” (hi)
.4019” - .0036” =
.3983” (lo)
Is this correct?
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OR this?
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P.D = .4019-.4050
((.0011” Max amount of plate per side) ÷ Cos30º) x 4 = .0051”
((.0009” Min amount of plate per side) ÷ Cos30º) x 4 = .0042”
.4050” - .0051” =
.3999” (hi)
.4019” - .0042” =
.3977” (lo)
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