How the dice are made
Updated: April 10, 2002
Most of the dice were made of nylon rod stock of diameter 19.1 mm.
This rod was cut into pieces of varying lengths in order to make
the dice. The cutting is done on a metal lathe, which helps ensure that
the two cut faces are flat and also parallel to each other.
Both the rpm of the lathe and the cutting rate have
to be optimized to yield good results. However, a bur forms at
the edge which has to be cut off using a hand knife.
The height of the dice was measured for h less than 25 mm using
a micrometer caliper with 0.01 mm precision. In most cases the
height varied from point to point by up to 0.10 mm. On this basis
the amount by which the two faces deviate from being parallel can
be estimated. More difficulty was found when h was small, in which
case the variation was up to 0.20 mm.
Several dice were made out of 7/8 inch hardwood dowel.
They were also cut using a similar procedure on the lathe. For wood,
melting is not a problem and no bur forms. However, wood is not an
isotropic material (that is, it has a grain).
Experimental data points of probability using the wood
dice are not noticeably discrepant from those with the nylon dice.
This page is still under construction.