Reply To: I’ve bit the bullet, Jan. 15, 2011

[princessclyne69]

Over the weekend I built the basic frame of the first module for the Wichita section. This is a simple rectangular one, the standard 24 inch wide by 6 feet long, but it will have complicated ones on either side.

This is part of a ‘module set’ as Free-mo would call it, with five or six tracks spanning three modules but just two tracks on either end. It fits in a space 18 feet long, which is as long a straight run as I can get and still have room for turnback loops at each end. So the frame so far is literally just that, two ends and two sides, plus the top which I’ve already marked track centerlines on. I’m not positive how these will line up so I’d rather not take it any farther until I have all three frames built. The two at the outer ends are the Santa Fe and Rock Island interchanges. Sorry to report there’s no room for the Frisco. I might still buy a Proto SW9 and letter it for Frisco 261, which spent its entire career in Wichita and is still there to this day in the GPTM, painted as BN something, which is how it came to the museum.

I like to do a lot of pre-fabrication, so I have at least six pre-made legs, several 24″ end plates, and other various components so assembling this one went quickly, if not well. The two sides were the same length to within 1/16″, but there’s some lack of squareness due to the sides being slightly bowed. I normally put about two 1×3 intermediate braces in, so that’ll be solved. One of the end plates is slightly twisted end to end, so I brought in the top slightly inward from the end of the side, and I’ll laminate some cardboard on it and sand it flush, so it’ll square up fine when assembled. I didn’t try to add leg clips or any of the other detail components since I’ll be out for a few days, but I prefer to add those on the bench, at a comfortable working height, so I’ll bring the frame back down later. I’m not real concerned with end-to-end parallel alignment, because the fabrication platform is flat enough that the screw adjustment on the legs will make everything work out. A bigger issue concerning tolerances is that the top of the frame sections need to align within perceptible limits by feel, something less than 1/16″, but the tolerance on the width of the frame sections is greater than that. This happens because I buy the Baltic Birch in larger sheets and rip it to about 5-7/8″ width, but the repeatability of my cutting, over time, isn’t that great. (Bear in mind that the sheets are furnished in exact metric sizes with a couple mm tolerance, but aiming for 6″ nominal brings it closer to the 5-7/8″ minimum.)

Laying out the plywood top with track centerlines makes it a lot easier to design the frame geometry, as opposed to the sections of the layout that are just track crossing open country with an occasional scenic feature. (I’m not playing up to the stereotype that Kansas is relatively free of scenic features, but I’ll just say that most of them are fairly uncomplicated.) As it is, I have several #5 turnouts in the interchange tracks and the WTA industry trackage that I’m not entirely confident as to them all fitting, so it’ll be interesting in the coming months.

Ron Merrick