08-20-2018, 06:11 PM
(08-20-2018, 10:05 AM)EOU Wrote: Well we guess that settles the debate concerning whether a straight edge can be sharpened to the level of a DE razor blade. In explanation of how the PT50B with 5 grams of resolution calculates BESS numbers it goes like this; anything calculated at/including 7.4 grams down to 2.5 grams will be displayed as 5 grams. Anything above/including 7.5 grams up to/including 12.4 grams will be displayed as 10 grams. In theory, the impossible, a reading of "0", would be possible with a PT50B and to a much lesser extent a PT50A due to this rounding function. In fact, a PT50C with 25 grams of resolution might have given these YouTubers a reading of "0" with their straight edge razor. Having offered up this explanation, it is misleading because, in reality, all values that fall outside (or inside however you choose to look at it) the resolution of the instrument are just noise.
In any event, these guys did offer up a very entertaining demonstration of the capabilities of a PT50B. We do wish that they would take better advantage of the knife fulcrum but, in fact, when working with edges that are very sharp (under 150) use of the knife fulcrum becomes less critical. Thanks to SHARPCO for bringing this to the Exchange.
In my experience using the PT50A tester freehand, I found that you have to be really careful not to move the blade horizontally or contact the media with the knife at an angle. Instead of true push cutting I add a slicing component to the test.
I have to be super slow contacting the media, with the edge even on the horizontal plane, or my readings are misleadingly lower.
Like EOU, I would have liked to see the fulcrum used.
Ed K.