A cylindrical probe which will take more accurate hits on thread holes.

That's the email I got upon entering the shop today. I was using a 1 x 10 styli for a part with 3-48 & 6-32 threaded holes. Just trying to get a decent location within tolerance of +/- .005. Now, the customer (we are the sub-contractor) is "coming in today with a cylindrical probe which will take more accurate hits on thread holes". I checked some of the postings in the forum and it looks like there's a lot involved and the results are sketchy.

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Wes Cisco over 9 years ago

A "shank" probe will only give you the location of the minor diameter. I have watched thread locators pulled to one side, for a variety of reasons. How would one check an 0-80 thread using auto-circle/pitch, or similar threads. Engineers truly need to stop attaching unrealistic tolerances to thread locations. My favorite is when they attempt to apply MMC to a threaded hole. Good luck with THAT one.

and yet it continues to happen, day in, day out. <facepalm>

Yes. Discussing this with an engineer on the yahoo Y-14.5 board one day, I was told, 'Engineering design should not be restricted by what manufacturing and inspection are capable of. It is their job to make and inspect what we design.'

If you really want to have some fun, look into SYSTEM 21 vs. SYSTEM 22 thread inspection.

for example: http://www.johnsongage.com/technical.shtml

Thanks again for everything Ironhoe.
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Wes Cisco over 9 years ago

A "shank" probe will only give you the location of the minor diameter. I have watched thread locators pulled to one side, for a variety of reasons. How would one check an 0-80 thread using auto-circle/pitch, or similar threads. Engineers truly need to stop attaching unrealistic tolerances to thread locations. My favorite is when they attempt to apply MMC to a threaded hole. Good luck with THAT one.

and yet it continues to happen, day in, day out. <facepalm>

Yes. Discussing this with an engineer on the yahoo Y-14.5 board one day, I was told, 'Engineering design should not be restricted by what manufacturing and inspection are capable of. It is their job to make and inspect what we design.'

If you really want to have some fun, look into SYSTEM 21 vs. SYSTEM 22 thread inspection.

for example: http://www.johnsongage.com/technical.shtml

Thanks again for everything Ironhoe.
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