Large compass for Staedtler lumocolor

A pair of plastic parts to create a compass for marking large circles on thin materials such as leather, fabric using a Staedtler lumocolor pen. The central part is designed to allow the material being marked to be sandwiched between a large magnet and a thin steel plate. This way of temporarily attaching the compass to the material being marked means that you can perform the marking without making any holes. The part has a 5.5mm hole that will fit the shaft in the centre of many of the neodymium magnets that are readily available. Typically you'll need to remove the eyebolt provided with the magnet and replace with a suitable bolt and oair of loosely tightened securing nuts. The central part has a groove to allow a piece of fishing line or braided nylon to be looped around and which is free to rotate. The other end of the line is threaded through a 3mm hole in the other part which is carefully dimensioned to fit a Staedtler Lumocolor pen. The interior end of the 3mm hole has an en