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Re: True Position Gage

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Posted By<" ">Randy on March 02, 2002 at 18:35:00:

In Reply to: True Position Gage posted byAlex D. on January 25, 2002 at 20:04:09:

: When designing a true position go/no go fixture for a four bolt hole circle from a center point and all locations located at their absolute nominal, would I just reduce the diameter of the location pis by the allowable true position circular area?
: Example; Hole dia.= .472-.476
: True pos.= .008(M) True pos. circular area limits = +/-.0028
: Reduce "ALL" pins. .472(L)-2(.0028) = .4664

Alex,
If I'm not too late. You make the pins of the fixture less than the print size of the holes by the amount allowed in your
true position calculations. You would need no 'no-go gauge', it fits or it does not. However, your fixture must be VERY accurate.
It is best if your fixture was checked on a CMM machine to see at what true position IT is before you used it. If you are doing
true position you must have an accuracy requirement or a production fit and function requirement. If the second, then you could
get away with your fixture as THE standard after a few cycles of prof that it paid off with product function.

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< "> Subject: Re: Re: True Position Gage

Comments: : : When designing a true position go/no go fixture for a four bolt hole circle from a center point and all locations located at their absolute nominal, would I just reduce the diameter of the location pis by the allowable true position circular area? : : Example; Hole dia.= .472-.476 : : True pos.= .008(M) True pos. circular area limits = +/-.0028 : : Reduce "ALL" pins. .472(L)-2(.0028) = .4664 : Alex, : If I'm not too late. You make the pins of the fixture less than the print size of the holes by the amount allowed in your : true position calculations. You would need no 'no-go gauge', it fits or it does not. However, your fixture must be VERY accurate. : It is best if your fixture was checked on a CMM machine to see at what true position IT is before you used it. If you are doing : true position you must have an accuracy requirement or a production fit and function requirement. If the second, then you could : get away with your fixture as THE standard after a few cycles of prof that it paid off with product function.

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