With a tip of the hat to Matthias Wandel ( https://www.youtube.com/watch?v=EqciYYiwlrQ&t=0s) here is my version of a chainsaw mill. It had to be cheap, simple to build and operate but still be effective. I had to ensure that when the chainsaw was mounted to the carriage the blade was parallel to the 2 x 4 timber guide. I also cut a short length of timber equal in width to the distance between the face of the 2 x 4 and the inside kerf of the chainsaw to help gauge the cut board thickness. I found that several light passes were more effective than trying to rip through all at once. I feel that I have achieved my goals :)