Bench Work Standards
Module frames should be made from nominal 1 x 4 pine lumber or plywood (the actual size of the board is 3/4" x 3 1/2"), #2 grade or better. For added strength, one might want to use a piece of hardwood such as oak in the frame on the module ends where they'll be clamped together. The hardwood will hold up better against the pressure of the clamps. 1/2" plywood is suggested to be secured to the top of the framework. Therefore the overall height would be a minimum standard of 4". While 1/2" plywood is recommended for rigidity, homosote, suspended ceiling tile, or rigid insulation foam can also be used to reduce the weight of the module. If such material is used for the top, the framework should then be made more sturdy and the lightweight top material should sit down into the frame so the soft edge will not be exposed to damage. Veneer plywood has also been successfully used for the framework. However, we recommend not using plywood that is less than 1/2" thick (5 ply veneer).
Using this standard 4" height will allow all modules to fit against one another neatly. If however, you wish to build a module with a scenery profile that is NOT totally flat across the end, you may of course do this, but you will have to allow a space under the mainlines in the bench work where C-clamps can go to attach to the next module. 2" to 3 1/2" C-clamps are required to connect and hold the modules together. Generally, 24" should be the standard width at the module end where it fits to the next module, although you may build modules with any width above this that you desire. This would provide as much extra room as needed for any purpose the modeler desires. Remember when designing your modules, that they will have to fit in your car, truck, or van for hauling purposes.
Legs should be built to a length which allows the modules to adjust to a standard rail height of 50" on uneven floors. However, you may choose any height which fits your needs. This height (50") was selected to give a more realistic vantage point for viewing the modules and has received quite a few compliments from the viewing public, some people saying that they felt they became much more a part of the scene. We have found that legs built in an "L" shaped configuration made from 3/4" lumber seem to work best. See FIG #2. The "L" shape eliminates the warping effect that is a problem with legs that have been made by ripping a 2 x 4 in half. A block of hard wood cut to a size of 2 1/2" long x 1 1/4" square with a hole drilled clear through the length will allow a carriage bolt to thread through for leveling. This block should then be glued and nailed flush with the bottom of the leg. Be careful not to drive a nail through the hole in the hardwood block. A "T" nut with no less than a 1/4 x 20 thread (5/16" x 20 preferred) and no less than 9/16" threaded shaft should be driven into the hole.
If you prefer, a threaded brass insert may be used instead. 1/4 x 20 threaded carriage bolts with a length of 3" to 4" screwed into the bottom of the legs with 1 1/2" exposed will serve as the levelers for the module. We recommend not using a carriage bolt smaller than 1/4" diameter because it can bend if the modules are slid around a lot. Larger carriage bolts and "T" nuts such as 5/16" or 3/8" diameter will endure better in the long run. Also the 5/16" and larger "T" nuts usually have holes for screws to hold them in place so they can't work loose. The 1/4" "T" nuts have only small spikes to hold them in and can work loose over time, as has happened to our group several times.
Now take the two legs and glue and screw lateral bracing members (made of strips of solid wood or plywood) up from the bottom a distance of 6" and 36" (for modules with a 50" rail height). This will create a "paired leg" that can not wobble from side to side. See FIG. #3a. Do not attach the paired legs directly to the module end. The head of the bolt used to attach the legs will protrude on the outer surface of the end and will not allow the modules to clamp together tightly. This will produce a gap that can not be easily spanned. Instead, these paired legs will eventually bolt to "spandrels" within the module bench work. See FIG. #4.
If you plan to use 1/2" electrical wiring conduit to make the diagonal leg bracing as described below, you may want to raise the lower lateral brace somewhat. This will allow you to use broom handle retaining clips (also called "C" clips or tension clips) on the lateral bracing to hold the diagonal bracing when the modules are transported. See FIG. #3b. Broom handle retaining clips are available from most any hardware store.
Then simply clamp the two "paired leg" assemblies to the spandrels and drill a hole for a bolted connection. If 1/4" diameter bolts are to be used, be sure to use a 17/64" drill bit to make a hole that the bolts will slip through easily. One bolt at the top of each leg will be enough to secure the paired legs to the bench work.
Now you produce and assemble diagonal braces from the legs to the bench work or from legs to legs. This final bracing will prevent the module from wobbling end to end (see FIG. #6). This we have accomplished with the simple process of using 1/2" ID thin walled electrical conduit which can be acquired from your local hardware store or commercial electrical warehouse. The price is about $1.50 per 10 foot length. For most modules, one 10' piece will be sufficient for all the braces needed. Cutting the conduit into 4 equal lengths of 30" long and flattening about 4" of both ends of each piece creates a strong but lightweight brace (see FIG. #5).
If a short module (about 4' or less) is to be built, then you may want to smash a 4' length in the middle of each piece and drill another hole so you can bolt the two pieces together to form an "X" brace.
Now bolt the conduit braces to the bench work and/or legs. Set the modules up and clamp the units together. You'll find that the more bends and branches you add to a layout the more stable the layout will become, to say nothing of the greater appeal to the eye!