Well, tonight I got home from the oddest exhibition I've been to, to find a package in the mailbox.
I decided to order some 13' underframes as I had several Kp tops that needed undergubbins. So, for a start, what do we get.
A floor, 2 solebars, 2 wheelsets, a brake cylinder and 2 sets of cast non working couplings. The length of the floor scales out at 20'10", which is not too far off the 21' of the real thing.
A quick check revealed that the solebars would not fit into the intended spots on the cast floor without some work. I drilled out the axle holes with a 1.5mm drill by hand until the cone on the wheelset could only just be seen. There should be less than 1mm between the wheel and the inside of the solebar at this point. The first solebar is then glued/soldered into position with the ends equidistant for the ends of the floor (I grabbed the 5 minute Araldite again, solder might be easier). Leave to set/cool. The second solebar is then attached with the wheels in place in position so that the axles are square.
Don't worry if the solebars don't match as you can trim them up afterwards.For some odd reason when I tried the underframe on the track afterwards it rocked quite chronically, so I had to bend the floor a fair bit to get it to sit flat on the rail's.
The main problem with this for the scratchbuilders among us is that the cast floor makes any cast top sit too high. To solve this I cut a piece of 2mm plasticard (about 11.5mm wide), and having removed any whitemetal tabs on the back of the solebars, then use the plastic as the central base for the underframe, andproceeded as before.
The resulting underframe seems to sit a lot flatter. The rolling resistance seems to be OK (not great but not too much drag) but should improve with a bit of running in. The solebar miss match at the ends is a bit of a worry, as is the squareness issue ( I'll put a couple more together later today to see if its any better)
Despite the faults, I think I will be buying some more of these.
UPDATE: Here's a picture of the second underframe under one of my Lc tops, with a Peco version for comparison.
I think that the solebars should be closer together as while they are the correct height (as measuerd from plans), they look far larger as they are not hidden under the wagon as well. I might try painting them a darker colour to trick the eye away from this. I trimmed to solvars down at the end so that they were square, and the length was just right for my Lc, so thats now something I'm not worrying about.
(also note that the Trackgang underframe on the right has had the head stocks and brake ratchet added by me from my own castings. They don't come with the kit. And i should add that I have no financial links with Trackgang products, but am open to a little bit of bribery:v)