How to Measure Concentricity Correctly

[Stijloor]

Re: Concentricity Measurement - How to correctly measure concentricity

Hi. I'm new here and have a related concentricity question:

We have a small part with 2 stepped inside diameters in the same larger bore: .116" and .172" and .1805", which is also datum C.

There are concentricity callouts for both:
for the .116" diameter "within .008 dia. to C" and
for the .172" diameter "within .006 dia. to C"

How is concentricity measured when comparing inside diameters only?

I understand the concept when comparing an O.D. to the I.D. but I am totally confused on this.

Thanks! Julie

Julie,

Please help us with clarifying what GD&T Standard is used:

• ASME Y14.5M-1994
• ASME Y14.5-2009
• ISO 1101

 

[qualityperson]

Re: Concentricity Measurement - How to correctly measure concentricity

Stijloor,

Honestly, I don't know.
The customer drawings don't list any of these.
The only reference from this customer on a different part drawing
is ANSI Y14.5-73.

 

[Stijloor]

Re: Concentricity Measurement - How to correctly measure concentricity

Stijloor,

Honestly, I don't know.
The customer drawings don't list any of these.
The only reference from this customer on a different part drawing
is ANSI Y14.5-73.

Can you attach a part of the print with the callouts on them?

Concentricity is the most misapplied/misinterpreted control there is.

 

[optomist1]

Re: Concentricity Measurement - How to correctly measure concentricity

Jim is correct....many times concentricity is not correctly specified, meaning another geometric control would suffice.....never "measured/gaged it myself" yet from the pages of Elsmar it is expensive to ascertain....concentricity is usually "correctly specified" for parts such as turbine disks/rotors turbo/machinery - optomist1

 

[normzone]

Re: Concentricity Measurement - How to correctly measure concentricity

" How did you accumulate 200 yrs of experience? Just Wondering, Doug "

It's kind of like dog years. Every week spent engaged in QC / QA / Inspection / Auditing ad nauseum ages you ten weeks worth. I personally was in my twenties when I asked too many questions and wound up working in this field, and just a short time later now I'm almost sixty.

 

[Lafir Ali]

Good mrng to all ... the info you shared how to measure concentricity was very useful , but clarify me how to contorl concentricity?

 

[danno101]

What about the hole concentricity of a hole that is tapered in the part? I have been told that meausuring concentricity for a tapered hole is not accurate. By the way, we use a fixture with a depth mic with a pin perpendicular to the mic. Then we measure, rotate, measure, rotate the pat for an average wall thickness.

 

[optomist1]

how about a dwg or sketch??