Quartering Test: Due to the destructive nature of both splitting test
procedures, and inhomogeneity both within and between individuals, repeatability is not directly testable, in the sense; if the cut plane exists though the (longitudinal) pith at an arbitrary radial alignment, how close is the result
to the (hypothetical) result of a cut through the pith at some other arbitrary
alignment. In order to test repeatability, after the splitting test had
been conducted, each of the two halves were halved again (into quarter
rounds), and reassembled with the small end in a self aligning jig set in
a vice. Four measurements were taken, providing the spatial relationship
between every quarter round. Openings between adjacent quarters were
taken to be the average distance between faces, as there were two measurements for each half
round (Figure \ref{751922}). In the splitting tests using half rounds the constant, 1.74, is derived from the distance to the neutral plane of bending from the outer surface, following the same logic as was presented in \citet{Chauhan2010} to calculate 1.74, a new constant (2.079) can be calculated for the quarter round tests. Assuming the sample possesses a round cross section, the cord of the circle perpendicular to the plane of the cut through the centre of mass for each quarter can be calculated using Equation \ref{eq:qt_cont_1} . Half the cord can then be calculated as a function of the radius (Equation \ref{eq:qt_cont_2}) and the distance from the outer edge of the circle to the centre of mass calculated as a function of radius (Equation \ref{eq:qt_cont_3}). Rearranging this constant (as per \citet{Chauhan2010} Equations 12 - 14 and updating to use diameter rather than radius) gives a constant for quarter round testing of 2.079 (Equation \ref{eq:qt_cont_4}).