SM32 coupling converter waggon

I want to use my Big Big Ruston to pull my harvest waggons, only there's a problem. The Ruston still has its knuckle couplings, which I want to keep, so won't couple up to anything other than Big Big stock. So, I've made a converter waggon with a knuckle on one end and wooden buffers on the other to match the harvest waggons.

I've loosely based it on an old Saltford Models twin tank waggon design, using the same basic materials (lolly sticks and strip wood) as I used for the harvest waggons. I also found a pair of Tri-ang couplings on eBay and again used Binnie curly spoked wheels but paired with Binnie  Ffestiniog 'late slate' axleboxes.

Here's the body/chassis;

It measures 90mm long and 66mm wide, with the bed being 78mm long. I've extended the frames past the bed, which is a feature of the Saltford design, mainly to help take the eye away from the knuckle coupling which will sit on one end. The extra piece of wood behind the left end in the photo above is for the knuckle.

To position the knuckle I took the measurements from a Big Big skip, and marked out a pivot point 9mm back from the buffer beam, and to control the sideways movement I drilled holes for two pins which sit 9mm apart. These had short lengths of brass rod inserted into them. To hold the knuckle in place I drilled a 2.8mm hole and epoxied a 6BA screw, minus its head, into it. Then I turned a brass sleeve and washer for the coupling to pivot on, being secured with a nut;

And with the knuckle in place;

Note the rectangles of white .020" plasticard glued inside the frames. The axleboxes I'm using should, according to Binnie's scratchbuilders help page, be used with the frames 50mm apart which I feel gives too much sideplay in the axle so I've effectively reduced the inner frame width to 49mm.

Also note the styrene spreader plates on the frame sides, I've used this little detail to help tie this waggon to the harvest waggons where I've also used spreader plates on the frames, to suggest that they all came from the same workshop. Which of course they have.

Here it is with the wheels in place;

The axleboxes are epoxied in place.

I've fitted dumb buffers to the other end, notched and spaced to match my harvest waggons, along with a coupling hook made from 1mm brass rod fitted into a hole drilled in the buffer beam, which has a styrene plate around the shank;

Again I've used Citadel Agrax Earthshade for the woodwork and Vallejo Black Grey for the ironwork;

Underside, showing the knuckle;

And in use;

It works well enough, although a little more weight might be useful. Propelling is a problem, but that's down to the knuckle couplings riding over each other, but I tend to run trains in circles anyway.

An enjoyable little project, it's not prototypical by any means due to the knuckle, and I'm sure that some would say the best solution would be to modify the loco, but I like it as it is. It does match the harvest waggons despite being outside framed, which was important to me.

Paul.