Locating The Screw Holes - End Plates

Jigs - The 2" (or 1 1/2") Block of Wood
One thing I've learned in doing carpentry and machine shop work is the importance of "jigs".  They make life so much easier when it comes to assembling bits-and-pieces of wood and steel.  We'll be using a couple of jigs to simplify our work, act as a 3rd-hand, improve our accuracy, and make the project more enjoyable. Our first jig is simply a block of wood 1 1/2" thick (if we're using 1 1/2" Styrofoam) or 2" thick (if we're using 2" Styrofoam) and about 12" or 18" long.

Take a piece of 2"x 4" or 2"x 3" economy or construction grade spruce over to the saw service and get them to chop the lumber into several pieces - about 4 pieces should do the job - that are 12"-18" long.  Next, get them to rip the blocks in pieces that are 1 1/2" or 2" thick (depending on whether we use 1 1/2" or 2" Styrofoam).  It's okay if the thickness is a bit more than the 1 1/2" or 2". But it's not okay if the thickness is less.

We now have a bunch of wooden blocks - jigs - that we will use to mark the location of our screw holes and to help us assemble the bits and pieces of wood together. Take a pen and mark the thickness as we've shown below. A picture's worth a thousand words, so here's a few hundred.

Locating The Screw Holes - End Plates
Our module frame will be held together with wood screws and wood glue.  So, we need to locate the holes for the screws.  We'll start off with the End Plates as they're the easiest to do.  It will give you a good idea of how we locate the holes for the other pieces.

1) - First you need a good flat work surface.  Make sure there's no sawdust crumbs, glue blobs or other obstructions on the surface as these will throw everything out of kilter.  

2) - Next we make a screw-hole marker (our second jig).  Take one of the triangular gussets and make a mark at the 1 1/8" point from each end and in the middle as shown below.  We'll be using this marked gusset to locate the screw holes.

3) - Place the end plate "Top" down on your work surface and "Out" facing towards you (now you know why we marked each piece "Top", "Bottom", "In", "Out", eh!?).

4) - Place your 2" (or 1 1/2") block of wood alongside one end of the end plate.  Draw a straight line along the edge about 8-9" long.

5) - Place the marked gusset on top of the block and draw a line along the top edge and the side edge of the gusset.  (You have now roughly located where that gusset will go.)

6) - Transfer the locations of the screws from the marked gusset into the lines marked on the end plate as shown below.

7) - Complete the location of the screw holes by drawing a line mid-way between the two long lines as shown below.

You don't have to be exact to the 1/64", 1/32" or 1/16"of an inch in locating the screw holes.  The accuracy will be in locating the gussets which will be covered later on.  We've now completed locating the screw holes for one end of the end plate.

8) - Repeat Steps 3 ) to 7) for the other end of the end plate.

9) - Repeat Steps 3) to 8) for the other end plate.

10)  Your end plates should resemble those shown below. 

Simple, eh!?

Next we mark the screw holes for the side pieces and middle cross member using the same procedures - but with a slight adjustment.