We need very thin drawbar bases to pass between the chassis and the wheels. I chose Makette KKK1, with (relatively) large elongation. Presented in the form of a photo-etched nickel silver plate containing 35 copies, so to equip… 17.5 wagons (!), they are quite cheap. But, currently (2014), they are difficult to find in this form.
Note: I tried plastic Roco models, but they don’t fit!
The making of these drawbars does not pose any difficulty. Just avoid tightening the assembly tabs. I was worried at the beginning of the height adjustment problems, since there is no adjustable NEM box on this model. But in fact, by tilting the box tail at 45°, the desired height is substantially obtained. Nevertheless, the small thickness (0.3 mm) of this tail makes the drawbar lack rigidity, and it seems very difficult to add a reinforcement. If you want to burnish the drawbars for more discretion, do it before the construction, it will be much easier.
It is naturally necessary to trim all the reliefs between the bogie pivot and the headstock. Fortunately, there are few. The drawbar base must be positioned against the headstock. For fixing, if possible, I prefer M2 screws screwed in ø 1,6 holes. A priori, do not bother tapping these holes, but I do it anyway! For adjustment, begin by tightening screws moderately, and move the drawbar. There is a good chance that it will get stuck in an oblique position. Then loosen the screws gently until the drawbar comes back to its centre position.
Using screws is impossible for flat wagons, on which I then glue the drawbars with superglue. Thin double-sided adhesive doesn’t hold in the long term.