2001年7月17日 · First, the tolerance zone is a cylinder located at the true position of each hole, so the diameter symbol should be added both at PLTZF and FRTZF. Second, the tolerance value of the lower segment must always be a refinement of the tolerance value of the upper segment, so the tolerance value at lower segment should be smaller than .016.

2009年7月2日 · [TRUE POSITION|.006|E|F] (with basic dimensioning to datum points on datums E & F) When calculating the true position without a diametric symbol is it necessary to double the positional measurement? ie. if the position checks .0084 from nominal is this a true position of .0084 (.0024 O/T), or is it a true position of .0168 (.0108 O/T)? Jeanne

2006年11月19日 · Positional to 1 hole relative to a surace reflects perpendicularity or any other angularity symbol which is the orientation. Why place positional when the appropriate symbol should be perpendicularity, parallelism or angularity? Doesn't make sense to me. This is just something that I have seen over the years - pet peeve. Dave D.

2005年11月11日 · In short, the mis-use of "True Position" really irks me. In the '09 Y14.5 standard; "1.3.64 True Position true position: the theoretically exact location of a feature of size, as established by basic dimensions." "7.2 Positional Tolerancing Position is the location of one or more features of size relative to one another or to one or more datums.

2016年7月14日 · In the end, it is pretty much semantics. The standard says that "true position" is the perfect location. The symbol then provides a tolerance around this perfect location. When teaching a GD&T class, I make a point of this distinction, and try to get everyone to call the tolerance the "position" symbol.

2009年11月4日 · Below the standard True Position dimension is the word "CODED" followed by a True Position symbol with two quadrants blacked out. I have three different versions of this callout, each having different quadrants black out.

2008年6月4日 · Here is a sketch (If I've managed to load it correctly) where there are 2 faces toleranced as true position. One is the end face of a valve feature, where there is a threaded cap assembled up to the face, and the other is a milled face on the right hand side to accommodate the two ports drilled through.

2010年4月9日 · But the true position call out of .005 will not since .004 is already well above this tolerance. i just want to verify, is the .005 call out based on where the holes are located in reference to the first true position (.017) and then the holes to each other need to be .005 or is the 1.05BSC also dictating where the 4 holes start from each other?

2006年11月2日 · The locating dimensions must be basic. You can calculate what the linear tolerances would be if you were not using the true position callout....remember the square inscribed in the circle Best Regards, Heckler Sr. Mechanical Engineer SW2005 SP 5.0 & Pro/E 2001 Dell Precision 370 P4 3.6 GHz, 1GB RAM XP Pro SP2.0 NVIDIA Quadro FX 1400 o

2006年11月13日 · It requires adding a symbol to the left hand view and requires adding a top view to show that this isn't a target point. 2009 - Figure 4-45 should have applied the datum symbol to an indicator for the cone angle to eliminate ambiguity.