Zero part to part variation - Gage R&R project

Eng.Hamad

Registered
Hi,

I work on a gage R&R project. I and my partner used a digital caliper to measure bolt holes of two rotors (12 points) each point is measured three times. When I got the results, there is zero part to part variation! what does this mean? Also, the gage R&R %study variation is 100%.

Can I conclude that MS is not adequate?

The MS resolution is 0.01 inch
Accuracy is 0.01 inch

Thank you,
 

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Eng.Hamad

Registered
Hi optomist1,
The rotor is ACDelco Silver 18A925A Front Disc Brake Rotor. I tried to find any drawings or specification limits, but I didn't find any. It seems to me that the best bolt size is M14-2. It is the bolt size that fits the cars that use this rotor.

I found a rotor that looks like the two I have. It shows bolt hole diameter 0.635 in
 

Jim Wynne

Leader
Admin
Hi,

I work on a gage R&R project. I and my partner used a digital caliper to measure bolt holes of two rotors (12 points) each point is measured three times. When I got the results, there is zero part to part variation! what does this mean? Also, the gage R&R %study variation is 100%.

Can I conclude that MS is not adequate?

The MS resolution is 0.01 inch
Accuracy is 0.01 inch

Thank you,
What does "measure bolt holes" mean? Size? Location? Please also explain the 12 points of measurement. What does the bolt size have to do with it?
 

Eng.Hamad

Registered
Hi Jim Wynne,
Sorry for confusing you.
The idea is to measure two rotor bolt holes (see attached). each rotor has 6 stud holes. I did not find any drawings or specifications except for product weight 19.3 pounds, and dimensions 12.33 x 12.33 x 3 inches. See excel file for gage R&R measurements.
 

Attachments

  • Zero part to part variation - Gage R&R project
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  • GageR&R_Measurements.xlsx
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Jim Wynne

Leader
Admin
Hi Jim Wynne,
Sorry for confusing you.
The idea is to measure two rotor bolt holes (see attached). each rotor has 6 stud holes. I did not find any drawings or specifications except for product weight 19.3 pounds, and dimensions 12.33 x 12.33 x 3 inches. See excel file for gage R&R measurements.
You didn't answer my questions.
 

Bev D

Heretical Statistician
Leader
Super Moderator
What are you atually trying to do? Do you work at the manufacturer of the rotor?
Why are you trying to estimate the hole size? That won’t help anything.
 

Eng.Hamad

Registered
What are you atually trying to do? Do you work at the manufacturer of the rotor?
Why are you trying to estimate the hole size? That won’t help anything.
I am a student, and I have a gage R&R project. I need to do it for any vehicle measurements using digital calipers. I chose rotors. I think estimating hole size helps to estimate the tolerance limits. I need tolerance limits in my project.

Thank you,
 
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