Glen,
The circle is outside the square.   As an example, if you have a x,y tolerance of +/- .005 this means that from a "Basic" location you could be +/- .005 in the x direction and +/- .005 in the y direction and still have a feature in tolerance in terms of location.  Mathematically, this equates to a diagonal of .007 from the "basic" true location of the feature.  Therefore with a x,y tolerance you would accept a part that had a feature located .007 (on a diagonal) from the "basic" true location of that feature.  Now if you look at that diagonal as being a radius from the "basic" true location of that feature, you would draw that radius around the outside of the square, having the radius touch each of the four corners of the square.  TP can also vary based on MMC (Maximum Material Condition) of a feature.

Tom Burek
Product Engineer
Ametek/Dixson

 -----Original Message-----
From: "Glenn Pelkey"@MAXTEK.COM [SMTP:PC :"Glenn Pelkey"@MAXTEK.COM]
Sent: Thursday, June 03, 1999 2:37 PM
To: [log in to unmask]
Subject: Re: [TN] True Position

 << File: ENVELOPE.TXT >>
 --------------------------------------------------------------------------  --
O.K. one more time.


Going back to the circle and square example, is the circle inside the
square
tangent to the sides as was first explained?


or,


Is the circle outside the square tangent to the corners as the math
explains?


Thanks,
Glenn


################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with
following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services"
section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
################################################################

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################