I guess I can disclose the method I came up with for calculating the approximate density of the partmades.
As my partmades were not uniform and had differing ammounts cut from them, I decided to accurately measure their displacement, rather than use a tape measure and attempt to calculate their volume.
I had a short length of 250mm PVC pipe, sealed one end and filled it to the top with water.
The partmade was then put in a large garbage bag and lowered into the water until the bottom of the lathe mark on the handle was level with the water.
From there, the partmade was removed from the pipe, and I measured how far down the water level was from the top. Simple Pi R^2 H to get the displacement, weight/displacement=density.
The only innacuracy is that the volume of the entire handle isn't measured, but I figure all the handles should be fairly similar, so it should be close enough for getting relative densities between the partmades I had.
Despite all six partmades looking pretty much the same, their volumes varied from 3.65 to 3.87 L.
Their ranking from lightest to heaviest was not the same as their ranking from least dense to most dense, but there wasn't much in it.