Go and annoy the local hobby-shop who sells K&S brass - there is a rectangular section piece and a flat-bottom U that will fit closely over each other and pick through them until you fine sections that slide freely - Five things -
#1 the channels MUST be absolutely parallel
#2 feed the rails on the traverser via the channels
#3 the channels must be absolutely PARALLEL
#4 use the rectangle section as the rails and use the U channel as the top sliding section, attached to the underside of the table
#5 THE CHANNELS MUST BE ABSOLUTELY PARALLEL
Have fun!
