CJ OUT at Indy!!

Pete Beau · 09-05-2009, 05:40 AM

The first thing that must been done in any measurement system is calibrate it! For anyone in the barn today, check for calibration stickers on the measuring equipment being used. If there is none then the gage is suspect. However, that also means that all gages being used by anyone must be calibrated in order for everyone to be on a level playing field. As an example, I have been in some garages/ shops and the guys are using calipers that are decades old and look like they have been through hell; let alone been calibrated.

The second thing in a measurement system is Gage R&R (gage repeatability & reproducibility). Basically it is a method of determining the amount of variation that a measurement system has in relation to the specification/ tolerance of the feature being measured. The end result is given in the form of percentage of error in relation to the tolerance of the specification. What is the tolerance that NHRA assigns to combustion chamber or piston volumes? The specification is a minimum value; you can be bigger, not smaller. How much bigger or what is the high limit of the specification? From that point you can determine what the gage error can be.

Just some food for thought.

09-05-2009, 05:40 AM	#11
Pete Beau Member Join Date: Sep 2002 Location: The Mo-ta City Posts: 247 Likes: 59 Liked 31 Times in 12 Posts	Re: CJ OUT at Indy!! The first thing that must been done in any measurement system is calibrate it! For anyone in the barn today, check for calibration stickers on the measuring equipment being used. If there is none then the gage is suspect. However, that also means that all gages being used by anyone must be calibrated in order for everyone to be on a level playing field. As an example, I have been in some garages/ shops and the guys are using calipers that are decades old and look like they have been through hell; let alone been calibrated. The second thing in a measurement system is Gage R&R (gage repeatability & reproducibility). Basically it is a method of determining the amount of variation that a measurement system has in relation to the specification/ tolerance of the feature being measured. The end result is given in the form of percentage of error in relation to the tolerance of the specification. What is the tolerance that NHRA assigns to combustion chamber or piston volumes? The specification is a minimum value; you can be bigger, not smaller. How much bigger or what is the high limit of the specification? From that point you can determine what the gage error can be. Just some food for thought. Last edited by Pete Beau; 09-05-2009 at 06:22 AM.