weren't the best quality castings I've ever seen. A 'phone call would have had another set in the post but I decided that cutting out a brass disk and sliding some brass tube through it would save me waiting for a delivery. It would also make putting the slide bars together a lot easier - soldering brass near soft alloys isn't my idea of fun.
In the end I scratch built the lot using spare etch for the slide bars. The lost wax brass crossheads supplied aren't as good as Gibson ones would be but they do the job. My method saves a lot of fiddling and I think is more robust - important for a working model loco. Or maybe I'm just awkward.