In 3.4 Benchwork I identified that in Lynn Westcott's authoritative work How to build Model Railroad Benchwork, he identifies two ways to frame the railroad layout and three ways to support the track.
In this page we will discuss the second of the tthree elements of framework construction: L-Girder Framing
Design.
Lattice framing (also called L-Girder) is probably the most common benchwork type today for large layouts. It is easy to build, lightweight but strong, adaptable to any layout size or configuration. L-Girders are sized to carry the weight of the layout. In HO scale L-Girders are often 1x2s for the girder top rail, 1x3 or 1x4 for the girder itself. Girders can be attached to the wall or can be free standing on constructed legs and braces. The roadbed is either laid on top of the girder assembly (for panels and tabletop), on crosspieces (joists) or on adjustable cleats attached to those crosspieces.
Material
I discussed material selection in the benchwork main page.
L-Girder Construction
L girder consists of two components, the girder and the flange.
The
girder size is often based on the span between legs. In my case I used
1x4 on the lower level and 1x3s on the backdrop side and 1x4s on the
fascia side. The flange is nominally a 1x3 on the lower level and some
1x2s on the upper level. .
1. I used a jig for constructing an L-Girder. In this case I used a straight scrap of 4x4 for the jig. The jig is used to ensure the L-Girder (flange to girder) was at a 90 degree angle. The jig was not secured to the table.
2. The 1x4 girder was placed horizontally along the jig. I did not secure the girder with clamps but you could if you wished.
3. The 1x3 flange was placed horizontally aloang the jig. Again i did not secure the girder with a clamp but you could.
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Fasteners. In previous WWSL vers 1 and 2, I used 1 1/2" finishing nails to secure the flange to the girder. Those L-Girders survived 20 years of use without separating. I found the drywall screws were easier to use this time around, though if you rent a nail gun you can get all the L-Girder you need done really quick. I used drywall screws to secure the flange to the girder.
No matter what you you to secure the L-Girder, secure the flange on one end, then move down the girder installing a drywall screw/nail every foot. When I got to the end of the jig, I slid the L-Grider forward to finish the length's construction.
I have read that some layouts glue the flange to the girder before securing with screws or nails. I chose not to use glue.
The WWSL
WSWSL version 3.0 is made up of dimentional lumber l salvaged from WWSL version 2.0, some 20 years old. I chose to continue to use dimensional lumber rather than measure and cut plywood to the actual dimensional lumber sizes.
On
the lower level I used 1"x4" L-Girders on both the wall and front side
of the benchwork. This allowed me to maximize my recycling of L-Girders while allowing new construction to maximum support span lengths of greater than 8 feet between legs. (See Chart)
I joined the front L-Girders with an aluminum splice plate to ensure straightness. You could use scrap pieces of 1"x4".
For the legs I used 2"x2" lumber with a 22 1//2" wide piece of 3/4" plywood for strength.
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On the Upper Level I used all my 1"x3" L-Girders and whatever recycled 1"x4" L-Girders I had left for the wall side of the benchwork. I used 1"x4" 10 foot long L-Girders for the front. They too were joined with an aluminum splice plate to ensure straightness. I strengthened this L-Girder with the light bar, also made of 1x4's for strength (reduce sag).
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