Modeling Information
Benchwork is the term given to the structural assembly that supports the model railroad layout.
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 first of the two elements of framework construction: Butt joint framing. Since Westocott's book, a new term: open grid framing has been adopted by the modeling community, and I will start using it here.
Design. Open grid framing is a one layer scheme consisting of a perimeter frame with crosswise joists. The width and lengths of the framing is determined by the size of the grid based on the layout design, the type of track support to be used. and most importanly - the span distance between legs. Here is a chart I found that discusses material requirements for adequate span support.
span pic
Material
I discussed material selection in the benchwork main page (https://modelingthewwsl.blogspot.com/p/33-benchwork.html).
What I didnt cover was the problem with open grid framing using plywood framing. Wood screws into plywood edges are not as strong as in dimensional lumber. The solution to this is adding cleats at the corners to accept the wood screws or use wood construction connectors. These connectors are specifically designed to provide for securing wood-to-wood connections particularly good with plywood.
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Technique 1.Traditional dimensional lumber framing with wood screws.
Technique 2. Plywood framing with construction angles.
Technique 3. Framing clamped to plywood squaring jig.
Like opinions, everyone has a construction technique that works best for them. Building open grid framing is no exception. Techniques include:
- Cutting framing to size and using a framing square to ensure square joints. Each joint must be clamped, screw holes located, pilot holes drilled, and angles attached. Since the framing angles do not draw a joint closed like a conventional fastener, the joint must be tight and square before the wood cleat or metal angle is placed. Using framing angles as connectors is not a speedy construction method. Even with the angles, the open grid framing can be out-of-square.
- A technique I prefer for most projects is to build the frame on a piece of plywood used as a squaring jig. The framing is cut to size, the initial framing piece is clamped onto the plywood sheet. The second framing piece is adjusted for tightness and square and clamped onto the plywood sheet. The framing angles are clamped to the corner, screw holes are located, pilot holes drilled,
and angles attached. Corner gussets are installed and then the assembly is unclamped and the next framing corner is similarly constructed. This construction technique is particularly useful for flat top, shelf or panel track support systems.
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