Hey PSO's and drillers:

I purchased a steel span ruler from innovative with the peg on the end.  I measured my favorite ball - true span, from the inside of the thumb to the inside of each finger insert.

The thumb has very little bevel.

I called in the measurements to my local PSO - made it clear this was measured from the inside of each digit.  No issue. 

The ball after drilling was off by 3/16 and 2/16 on each finger respectively.

I met with the operator and he remeasured and said the ball was spot on.  The span ruler he uses has no peg.  He said the peg throws off the measurement.  He holds the span ruler slightly inside the thumb to compensate for bevel and pitch. 

How do you guys measure - true span - ??

Thanks friends.

VG

IMO, you should have different people use the EXACT SAME tool to do the measuring.  I say this due to my experience with enormous differences in the quality of the measuring tools themselves.

On tape measures used for basic carpentry, I have seen guys measure off 5 feet using one brand of measure, and then repeat it using another brand and discover the ending difference between the two was approximately 3/16". 

Same thing in the science industry, the old lab I used to work in was restricted to using only one brand of measuring instruments because of inconsistent results using multiple brands.

Hope this helps.

If it is needed to be said that it is the center edge then you should not be doing the measuring it, JMO.

That is the problem with a lot of technical writers, small little details get left out or are not properly phrased because they assume it should be obvious to the reader. JMO

and it was just a suggestion.

1/8 and 3/16 is more than ruler error.  I would ask that it is fixed.  If refused, I'd move op n to a new driller capable of hitting a span...  that simple