By Don Thompson and Don DeWitt
Part 2
Reprints from "The Herald" by permission of author.
Adapted for the WWW by Paul Yorke
| The first installment in this series dealt with theories of planning and laying out a module. Now to the actual building of the platform upon which the track work will be attached. The method described in this series allows an infinite number of sizes to be built. It will also develop woodworking skills in the modeler. The tools are simple and the work is not difficult, but it does require the ability to cut a straight line. Now, if we haven't scared you away, let's begin Chapter II: Benchwork. |
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Description We are going to construct a switching module
in three sections. These sections will be nearly identical, except for
joiners as described below. Let's begin with a description of the module. Each section is 64" long. When joined
together, they form a module 16' in length. When stacked, they will fit
into most cars with rear doors and collapsible seats. Since the overall
length is 16', the complete module will fit into a layout that also has
four 4' sections on the opposite side, allowing a loop to be assembled. The module will have a double track mainline,
but it could he built with single line. As built, it could be used as a
stand-alone switching layout, or it could be part of a larger home layout.
We decided on three sections (rather than four) to make turnout location
less critical. And, as a bonus, we also eliminate one set of bridge rails. The frame's stringers, cross-braces and
transoms are made of 1x3" lumber. The legs are 2x2" pieces ripped
from 2x4"s (more on this later). A complete list of materials for
the three sections appears on the main drawing, as does a glossary of terms. Let's get started Begin by cutting the wood. Be sure to get
dry, straight lengths of lumber that are as free from knots as possible.
If you have access to a furniture wood supplier, you might try to obtain
lengths of maple or oak. Bear in mind that the frame and supports are really
pieces of furniture that are going to he leaned on, moved around and bumped.
It behooves the builder to use the best materials available in order to
ensure a long and useful life. |
Follow the list
on the main drawing and when all the parts are finished we are ready to
begin assembly. We should mention now that good, square cuts are essential
for a well-constructed module frame. We use #6 and #8 dry wall screws because
they do not need predrilled holes and they will not split the wood. (On
harder woods - such as maple - starter holes may he necessary.) They work
well with an electric screwdriver and a phillips head bit. If these are
not available, or if you prefer, the equivalent countersunk wood screw
is as functional. However, you will have to predrill the holes. We use wood glue in addition to the screws
in order to get the tightest joints possible. Nothing can be more frustrating
than working on a wobbly module. With a little care during construction,
the finished product should support fifty or so pounds of layout without
swaying. It is best to work on a large flat surface. A 4x8' sheet of plywood laid on a table or workbench is an ideal work surface. The floor is another, but using it requires a lot of stooping.
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| Following the plan in FIG 2, lay the 1 x 3 x 62" stringers
on their sides and mark off the locations of the cross members. To be sure
that the cross members will be square when assembled, lay out the holes
on both stringers at the same time. We begin by placing one of the stringers
so that its three inch side is vertical. After applying wood glue to one
end of a 1 x 3 x 28 1/2" cross member, attach it to the stringer with
drywall screws at one of the locations previously marked. Repeat this step
until all of the cross members are attached to the stringer. Now attach
the other ends of the cross members to the second stringer using the same
procedure. A carpenter's square or a known-to-be-square piece of plywood
is of great value in ensuring true 90-degree angles.
Once the cross members are in place, we can install the 1 x 3 x 30"
transoms. These are the pieces that close the box, and they mount over
the ends of the stringers. The same glue-and-screw procedure is used to
secure them in place. Check to be sure that the frame is square and, if
so, set it aside and work on the other two. Once all are completed it is
best to leave them undisturbed while the glue sets. We've got plenty to
do on the decks anyway. Cutting the Deck and Roadbed Levels The deck or sub-roadbed covers the frame entirely and is made of 3/8"
plywood. A module that is designed for open roadbed where the plywood is
used only under the tracks would require thicker (1/2" or better)
material for rigidity. Use "good one side" which becomes the
top surface. The roadbed will be attached to this surface later. Where
dampness is a problem, use exterior grade plywood. Cut three pieces 30x64" and sand the edges as necessary. It's recommended
that the edges and bottom be sealed after cutting in order to prevent warping.
(The frame and legs will be painted for the same reason.) The roadbed covers the deck completely and is cut to exactly the same dimensions. Homosote is used here and, as this material is moisture-sensitive, both sides and all edges should be thoroughly sealed. A waterproof version of Homosote (identified by its green color) can also be substituted. For designs where the roadbed is open, the Homosote can be cut to fit or |
pre-cut, shaped roadbed can be obtained from
Bo Manufacturing (RD3, Box 375B, Kingston, NY 12401). They make a 3/8"
thick product that is quite useful for this purpose. Another possibility
is the blue extruded Styrofoam that builders use to insulate houses. It
can be glued to the deck with Liquid Nails and has the advantage of being
waterproof and will not warp. Once the deck and roadbed levels are cut
and checked, they should he sealed as mentioned above. They may require
more than one coat, and sufficient drying time should be allowed between
applications. The Legs There are many ways to make legs and attach
them to module sections. The most common is to use 2x2s ripped from 2x4
studs. (The reason for this can be seen at any builder's supply. Most 2x2s
look like an Irish shillelagh, with maybe one in a hundred being straight.)
They should be cut so the top of the rail is 42" from the floor. (This
is for S scale. In other scales the standard rail height may vary, so its
best to check the appropriate standards to determine the correct rail height.)
Slight variations in floors or leg mounting errors are corrected for by
using adjusting screws or furniture levelers in the bottoms of the legs. Whatever the scale you are using, the following
formula will apply: Leg Length = R(h) + T(t) + Rb(t) + D(t)
- S(h) +/- V This equates to: Rail (h)eight + Tie (t)hickness + Roadbed (t)hickness + Deck (t)hickness - Standard (h)eight above the floor. V is the adjusting bolt explained below.
The drawing for the legs and the leveling screws. For example, if the rail is code .125,
(1/8"), the ties are 1/8" thick, the roadbed is 1/2" thick
and the deck is 3/8" thick, then the legs should be 40 7/8" long.
However, to allow for variations in floor levels and leg mounting techniques,
we use adjusting bolts that have 1" of travel, or 1/2" in either
direction. Therefore, the final length of the leg is 40 3/8" which
will give us our 42" rail height with 1/2" of adjustment possible
in either direction. |
| Place one of the frames flat on the work
surface. As shown in FIG 1, position one of the legs in the interior corner
formed by a stringer and the first cross member from either end. (Notice
that the leg is not positioned in a corner formed by a transom and a stringer,
as this area must be kept clear to accommodate the C-clamps that will join
the sections together.) Once the leg is positioned squarely in the corner
and flush with the work surface, clamp it firmly in place and drill two
5/16" holes through the stringer, using the holes in the leg as a
guide. Repeat this process for the other 3 legs. It is a good idea to temporarily
assemble the legs to the sections at this time to ensure that they will
fit. When this is done, sand all surfaces as necessary and apply a coat
of the porch paint everywhere except the top edge of the frame. (The deck
will be glued and screwed to this surface.) After the paint is dry, we are ready to install the deck and roadbed. Lay the frame on the work surface with the unpainted edges facing up. Run a bead of glue onto all of these edges. Then place the plywood deck on top of the frame and begin screwing it in place using the drywall screws. A starter hole may be necessary, but we have found that the drywall screws generally go in easily and countersink themselves.A screw every eight or so inches should be sufficient. Take care that no screw heads protrude above the deck surface, as they will prevent the roadbed from laying flat. |
When this is done the Homosote layer is
applied in much the same manner, except that glue is applied all over the
deck surface and screws are only used on the peripheral edges. When all the surfaces are in place and
the glue is dry, the sections are ready for a final check before we start
laying track. It is important that the decks of adjoining sections fit
smoothly together, but it is more important that the transoms butt against
each other without any interference from the deck and roadbed edges. Inspect
the transom ends of each section to see that no deck surface protrudes
over the edge. If so, remove it with a rasp, plane or sandpaper. Now install
the legs on one unit and level them so that the roadbed top is 41 3/4"
from the floor. (The remaining 1/4" is the combined rail and tie height.)
When this is done, assemble the legs to one end of the next section and
join the other end to one end of the first unit using a C-clamp in each
corner. Adjust the levelers in the bottoms of the legs as necessary. Repeat
this procedure one more time to join to last section to the first two. We are now ready to lay track, which will be the subject of the next installment. |
