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Building a Module: Frame

Do you remember your first module?  My first module, a POFF, made its initial appearance at the Boy Scout Troup 964 Train Show on March 15 & 16, 2008. Actually, our module would be more appropriate based on the extensive tutoring and advice received from many NVNTRAK members.  This article describes the result of our collective effort.

From the prospective of a relatively new member, the continuing success of NVNTRAK is the result of your willingness to help others.  Please continue to answer the dumb questions and explain how to ballast track for the n-th time.  Although generally consistent, advice was sometimes conflicting.  For example, early on someone strongly advised against using Homosote—too heavy.  Later, at one of Cotton Bowen’s backshops, there was John Steitz burning up saber saw blades making a return loop, yes from Homosote. 

A key goal was to model the undulating terrain of the Piedmont region of Virginia with cuts and fills on each module.  This resulted in the decision to have two inches of foam under the track and up to 2 inches added for hills allowing a total of 4 inch elevation change.  Advise was to keep the module light, in this case a failure, with an ultimate weight, with legs, of 26 pounds.  The POFF was designed to meet all NTRAK standards.

Frame  

The frame was constructed from 1 x 4 dimensional lumber.  The front and back are white pine, exactly 48 inches long.  After seeing the stress that the two ends take from clamping and in transport, it was decided to make the frame ends from poplar.  Poplar was selected because it is relatively light for a hard wood, close grained, and can be worked easily.  For the deck luan was used.  When assembled with only screws for testing, the frame was too flexible—it needed help.

Two cross braces were added to the basic frame to make it more rigid.  Also the cross braces:

  • Keep the sides at a 90 degree angle to the top. With only “green” pine available, a 48 inch run will warp as it dries if it does not have additional support.
  • Provide additional support for the luan deck.
  • Have three 1 inch holes to provide conduits and support for wiring and stowage for the power-pole cables.
  • Have slots that provide storage for the four EMT legs.
  • Were cut down to 1 inch in the middle area not used for legs or wire to reduce weight.

Assembly

The next challenge was to get everything square.  The poplar frame ends and cross braces were cut as a set exactly 22.5 inches, with the ends square.  Each joint was glued with waterproof wood glue and clamped at a 90 degree angle with the sides vertical.  It takes some time, tapping, and reclamping to get it right.  All joints were reinforced with #8 by 1.5 inch wood screws in drilled and countersunk holes.  Chapter 5 of the “NTRAK Module How-To Book” recommends using dry wall screws.  However, dry wall screws are not designed to pull two pieces of wood together the way wood screws can. 

Before installing the luan deck, the front of the frame was clamped to a four foot straight edge to remove any warp in the pine.  The luan deck was glued and screwed in place with #6 by 1 inch wood screws.  Yes, all drilled and countersunk.  Since the top was not going to be seen, the good side of the luan was placed down.

At this point the basic structure of the POFF is complete.  Total cost to this point, $42.00.  Another article, part 2, will discuss the challenge of adding two inches of foam and laying track.