Experiments on Knife Sharpening John D. Verhoeven ... - BushcraftUK

YY = 45.5 mmLThese parameters can be inserted into Eqn. 1to give β as a function of X. When this wasdone and comparison was made to the valuesof β measured with the jig it was found thatthe values of β were too small by around 2degrees. Therefore Eqn 1 was modifiedaccordingly to the form:Holder barhβXHolder barguideRβ = arc cosine((R 2 +L 2 -Y 2 -h 2 )/(2*R*L)) -88 Eqn. 4.Figure A6 Geometry for the Tormek leather wheelA plot of this equation using the above leather wheel values for h and Y are shown in Fig.A7 along with the actual β values measured with the Tormek angle measuring jig. Thedata labeled Cor Rog is that calculated from Eqn. 4, and the data labeled Measured is forthat measured with the Tormek angle measuring jig. It is seen that fairly good agreementis obtained.One of the limitations of the Tormek angle jig is that it cannot be used for β values lessthan 15 degrees. Therefore the plots of Fig. A7 are quite useful for extrapolating down tovalues of less than 15 degrees.After grinding a blade on the ceramic wheel the asymmetry in the β angle must beaccounted for when setting up the blade to be honed on the leather wheel. Generally it isdesired to have the angle a bit larger on the leather wheel. Calling this increase in anglethe overangle, OA, it is desirable to have it be the same on both of the ground faces.Hence, one must be sure to clamp the blade in the holder using the same orientation as51