First off i would like to say hello to everyone..So hi :o

I'm new to gd&t as a inspector and have done some basic jobs which call for gd&t but some things have been holding me up in my progression. Iam based in the uk and work to iso9001 standards and wondered if someone could help me out with the drawing attached?

As i understand hole position tolerance is measured from the datums stated in the feature control frame. The drawing i have attached is from a customer who use's there own datum reference frame to take measurments from and restrict 12 degrees of freedom,Which i understand.

The part i'm confused about in the upper drawing arrowed is the positional tolerance that use's hole(Datum) "c" as the tertiary. Do use hole(Datum) B for dimensions left to right of itself and then C for dimensions above and below? So basically if i ran a line through B and a line through C (perp to each other)the point at which the two meet would be my coordinate system?

Also the same applys to the drawing below it where profile tolerance which calls up datums ABC. Where would my measurments come from? I have measured from the red line highlighted as it is parallel but is this correct?

Any feedback is greatly appreciated

Nick

I'm new to gd&t as a inspector and have done some basic jobs which call for gd&t but some things have been holding me up in my progression. Iam based in the uk and work to iso9001 standards and wondered if someone could help me out with the drawing attached?

As i understand hole position tolerance is measured from the datums stated in the feature control frame. The drawing i have attached is from a customer who use's there own datum reference frame to take measurments from and restrict 12 degrees of freedom,Which i understand.

The part i'm confused about in the upper drawing arrowed is the positional tolerance that use's hole(Datum) "c" as the tertiary. Do use hole(Datum) B for dimensions left to right of itself and then C for dimensions above and below? So basically if i ran a line through B and a line through C (perp to each other)the point at which the two meet would be my coordinate system?

Also the same applys to the drawing below it where profile tolerance which calls up datums ABC. Where would my measurments come from? I have measured from the red line highlighted as it is parallel but is this correct?

Any feedback is greatly appreciated

Nick

Hello, I am pretty new to GD&T so bear with me.

My co-workers and I have been debating about this issue for a few days.

If you open Example1.PDF, Datum C is measured from 1/2-13 Thread at 1.000". Datum C has a Surface Profile callout of .002 from Datum A & B. Example2.PDF shows that Datum C is measured straight from Datum B at 2.500". How does the 2 callout differ?

My co-workers are telling me Example 1 does not make sense because Datum B & C dimensions the thread from their location and the Position calls for A,B, and C. Clarification on this would be great! Thank you!

My co-workers and I have been debating about this issue for a few days.

If you open Example1.PDF, Datum C is measured from 1/2-13 Thread at 1.000". Datum C has a Surface Profile callout of .002 from Datum A & B. Example2.PDF shows that Datum C is measured straight from Datum B at 2.500". How does the 2 callout differ?

My co-workers are telling me Example 1 does not make sense because Datum B & C dimensions the thread from their location and the Position calls for A,B, and C. Clarification on this would be great! Thank you!

Hello,

I am designing a simple sheet of aluminum that has multiple holes 0.5 deep in CATIA. After it is machined, the goal is to insert steel pegs of diameter 1/8 in these holes, and I dont want it to wiggle around very much.

According to the ANSI standard for sliding fits, my desired tolerance of RC2 (just picked the one I thought would be best) says that my max tolerance can be 0.0003. That renders 0.125 + 0.0003.

The peg I would like to use is 0.125 +/- 0.0005.

Now, the maximum diameter of the peg can be 0.1255 which is greater than the max the hole can be ie. 0.1253 So clearly I cannot go that route. Can I have some advice as to how to approach this issue? I just want to know how much clearance I should have between the hole and the peg to have a good fit but not also be too small so that I cant insert it myself.

As you can probably tell, I am new to tolerances. Any help is appreciated. Thank you!

]]>I am designing a simple sheet of aluminum that has multiple holes 0.5 deep in CATIA. After it is machined, the goal is to insert steel pegs of diameter 1/8 in these holes, and I dont want it to wiggle around very much.

According to the ANSI standard for sliding fits, my desired tolerance of RC2 (just picked the one I thought would be best) says that my max tolerance can be 0.0003. That renders 0.125 + 0.0003.

The peg I would like to use is 0.125 +/- 0.0005.

Now, the maximum diameter of the peg can be 0.1255 which is greater than the max the hole can be ie. 0.1253 So clearly I cannot go that route. Can I have some advice as to how to approach this issue? I just want to know how much clearance I should have between the hole and the peg to have a good fit but not also be too small so that I cant insert it myself.

As you can probably tell, I am new to tolerances. Any help is appreciated. Thank you!