NavList:

Since we are talking about one of my favorite subjects I will take this opportunity to post some photos of two of my recreations. One of these is like the original Bygrave and the other one is like the German MHR-1 with a locking device. I described how I made these in prior posts. The first photo shows them both in their protective cases. The Bygrave's case is simply a paper towel roll with a releasable cable tie fastened across the top to keep it in. This model weighs only 6 ounces. The MHR is in a mailing tube with the same type of retention device but it weighs three times as much at 19.5 ounces. The Bygrave has the tan scale attached to a sink drain pipe and covered in clear plastic, the cos scale is simply sealed between two pieces of clear plastic forming a tight fitting tube, and the cursor is a line printed on clear plastic and then rolled into a tube that fits tightly on the cos scale. Also on the cos scale is the zig-zag instructions for using both ends of the cursor.

The MHR has the tan scale attached to a metal tube and covered in plastic just like the Bygrave. The cos scale is attached to a larger diameter tube in the same fashion and the cursor tube is made just like the one for the Bygrave. There are two cursors, just like with the original Bygrave, since only the ends are used to line up with the two scales. I put the zig-zag on the cos tube (instead of on the cursor tube) along with a condensed form to follow, similar to the original German made MHR-1.

gl