Before committing to building the frames I first obtained the necessary sheets of 6mm MDF for the top (I can hear all the plywood-advocates cringing from here). This was cut into 3'x2' rectangles by the DIY store for no better reason than it made it easier to take home in the car! The bare sheets were used for rough setting out - on the lounge carpet - making use of Peco point templates. You may notice that at this point the branchline met the mainline at a flat junction. I knew I wanted the station to be a certain length, and the fiddle yard to be wide enough for 8 storage tracks, so these were drawn on seperate pieces of cardboard so they could be moved around for the best positioning.
Outside frames were built out of 3"x2" softwood glued-and-screwed, ensuring they remained square until dry. Cross beams and bracing were then installed, also glued-and-screwed, made out of 2" x ¾" timber in a T-shape as per the diagram below, with holes pre-drilled in the upright pieces to allow routing for wires. This should ensure a high degree of rigidity to minimise flexing while the layout is being transported and during set up.
This may seem to be on the heavyweight side but since it was decided from the start that a van would be hired to transport it, and two people would be needed to operate it and therefore be available to set it up, I would rather over-engineer at this stage than deal with damage due to flexing when all the scenics are down! So having built the frames the MDF sheets were firmly screwed in place, making a VERY solid baseboard. Believe me it does not flex ;o)
A closer view underneath showing the T-braces and the wiring holes.
With both boards built attention turned to finalising the track-plan, mostly freehand with a marker and ruler but again using Peco templates for the points. Done in the garden as there is nowhere in the house to have both boards up for any length of time.
Here you can see the early planning of the flat junction for the branch on the far board, now superceded by the over-bridge idea, the beginnings of which are on the nearer board. The large blank rectangle in the foreground is where the cardboard template for the station sits.
To ensure good alignment between the two boards they were placed on edge on the flat wooden floor in the lounge and two 7.5mm holes were drilled right through one end frame approximately 4" from the ends and 1½" apart as shown below. Then the two boards were clamped together making sure the top surfaces were level with each other and the same holes extended 8mm into the adjoining frame. At the same time a further 9.5mm hole was drilled right through 10" from each end to provide bolt holes later. The boards were separated and 8mm Bullet-type Alignment Dowels from Station Road Baseboards fitted - the female halves glued and gently tapped into the blind holes, and the male parts glued and tapped into the through-holes. To reinforce the latter some 8mm dowel rod was glued and hammered into the hole from behind until they butted against the back of the male dowels. Measurement diagram below:-
Female dowels fitted into 7.5mm dia by 8mm deep blind holes
Male half of dowels fitted into 7.5mm holes drilled right through
Wooden dowels glued and hammered in to reinforce male dowels from the rear
M8 T-Nuts, again from Station Road Baseboards, were fitted into the two 9.5mm holes of one board on the opposite side to the join, and drilled T-Nuts fitted to the other board. Some M8 threaded rod was cut to length to fit through both end-timbers and a wingnut glued on each one with Araldite. The idea when assembling the layout is that the two boards are placed on the modified trestles and slid together so the alignment dowels engage. The two threaded bolts are pushed through the drilled T-Nuts and both end-timbers and screw into the threaded T-Nut on the other side, bringing the two boards tightly together.
T-Nut fitted to inside of baseboard frame . . .
. . . and with home-made securing bolt
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