Bevel angle vs sharpness

[EOU]

Hello Steve and welcome to the Exchange! Thought we'd weigh in concerning results using test clips vs. standard test fixtures. As you've already noted, there is a 20% differential in scores obtained using the two systems (add 20% to test clip results). This differential was calculated using knife and razor edges. If the test clip is first de-tensioned by wiggling one leg back and forth then the differential between the two becomes negligible. If you are witnessing greater than 20% differentials when measuring various wood working tools we would advance this theory; It is very possible that the shape and edge geometry of the tool accentuate the delta between the two results. It is often difficult to take extremely accurate and repeatable measurements using the standard test fixture due to it's physical constraints relative to the shape of the tool being measured. This is one of the primary reasons that disposable test clips exist. If this turns out to be the case we would think that 120% of the clip measurement would be the best representation of the edge sharpness level. You bring up an interesting point here Steve and one we would like investigate further. 

Once again, welcome to the Exchange and thank you for posting!