First, the round pin is placed into a mini-drill and its upper end is chamfered with a file. The square pins are already chamfered. To ensure that they are perpendicular to the draw bar, the pins are held in a block of wood drilled at dia. 0.8 mm to a depth of 4 mm. Soldering is done on the underside of the draw bar.
As for the square pins (photo), they are first pressed into their insulating support so that they protrude about 4 mm above the surface of the draw bar. The support will be removed after soldering.
The coupler (a Fleischmann Profi), held in the vice by a recovery NEM box (Ribu), has two 0,8 mm dia. holes drilled 1 mm from the rear and, of course, 2.54 mm — 1/10’ — center distance. Then its normalized tail is cut. It will be mounted on the draw bar already installed on the DMU, so that it can be adjusted to the right height.
It remains to pass a coat of gray paint on the new draw bar, to assemble the parts and to mount back the whole on the DMU. To make this easier, I release the rear bogie and let it hanging at the end of its wires, although this is not very wise… Don’t forget to mount the battery box back before the final assembly.
Et voilà, as we say in France (and in the USA too)…
The draw bar is too low by about 0.5 mm, due to the original draw bar clearance. But it's possible to catch up by playing on the brass piece folding. I have taken this into account in the dimensions given on the previous page. It’s the destiny of prototypes to remain perfectible, and we make practically only prototypes!