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Reverse Tolerance Limits

  • Thread starter Thread starter Maike13
  • Start date Start date
M

Maike13

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Is there any way to control the order of the tolerances in a limits dimension? On my drawings the lower limit always appears first, for example 1.990 - 2.010. Is there any way to reverse the order for selected dimensions, for example 2.010 - 1.990. The reason is, I am converting some paper drawings to Creo and the paper drawings use max material tolerancing, where ODs are toleranced 2.010 - 1.990, IDs are toleranced 1.990 - 2.010, etc. My client wants to maintain this same tolerancing scheme for the Creo drawings.
 
That is per ANSI standards. His scheme is backwards.
As to whether you can change it, not that I am aware of.
 
I eventually found a way to do this so I though I'd post it in case anyone else wanted to do this.
Suppose you want your final dimension to look like 2.005 - 1.995. First set the tolerance mode for the dimension to nominal. Enter the nominal dimension (in this case 2.000). For the Upper Tolerance enter -.005. For the Lower Tolerance enter +.005. Now switch the Tolerance Mode to Limits. Your limits will now be Upper Limit 1.995; Lower Limit 2.005 and the dimension will display as 2.005 - 1.995
 
Very clever. I love it when people figure out how to lie to computers to make them do what you want.
 
Computers do exactly what you tell them to do. It may not be what you want them to do, but they will do what you tell them to do.
 
OK. I should have said lying to the software. The cleverness comes from thinking outside the box. By inputting a negative number for the upper tolerance in order to get the smaller resulting number to be displayed first, you are lying to the software to get what you want. It's like when using the shell command, if you model the inside of the part and then input a negative number for the wall thickness, you get the same result as if you modeled the outside of the part and used a positive number for the wall thickness. I've never heard a PTC trainer teach these kind of tricks. I've learned them from "clever" people.

There's a lot more space outside the box than inside.
 

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