Next up is making the back that the framework (greyed
out) will get attached to. The center
panel is made from ½” thick MDF with an oak veneer that was a shelf from a
salvaged wine display rack. The veneer
is thick enough that I could run it through the thickness sander to remove the
finish and most of the stains. The
stains that remain won’t be a problem since it’s going to be painted. Once that’s done it’s cut to size on the
tablesaw. To cover the raw MDF edges I
will add an 3/8” thick oak frame cut tall enough to stand about 1/8” proud of
the panel to make a nice shadow line.
This is a change from the original plan where I was going to use veneer
tape on the edges. This tape has hot
melt glue already on its back and uses an iron to heat and attach it. The photo on the right is my jig for cutting
the 45-degree miters at the corners. The
jig gets clamped to the chop saw holding it in place. To set the 45-degree angle I used a clear
drafting triangle (leaning up against the saw’s fence) from when I was a
draftsman 50+ years ago. No CADD then as
everything was hand drawn. Once the
adjustable pivot arm is set in place it gets clamped to the jig’s base. The red arrow points to a sample cut piece.
There are quite a few ways to get the frame pieces to fit
perfectly around a panel but this is the one I use. It’s probably not the fastest but I get
really good tight corner joints using it.
The top photo has one scrap mitered piece clamped in place which was
located by using another scrap, also shown, to get the desired tight-fitting
joint. The bottom photo is a closer
view.
Next another mitered scrap is clamped at the opposite end
using the same locating process as the first one. That’s shown in the top photo. With that done the first actual piece gets
its right end mitered and set in place up against a spacer that’s the same
thickness as the frame and up against a stop block to set the start point. The lower right photo shows a close view of
that. The left lower photo shows the
marks for the cut length made using a small square and a 45-degree line made
with a layout square.
The left-hand miter can now be cut a tiny bit long on the
chop saw using the 45-degree jig. By
taking small passes it’s easy to sneak up to get a prefect gap free fit. The two lower photos show the end
result. Once fitted glue is applied to
the center panel then the just cut frame piece is set into place and pin nailed
tight. The same process is repeated for
the remaining three sides.
The left photo shows what the framed panel looks
like. The top right photo is a close
edge on view with the red arrow pointing to the driven in pin nail and the
bottom right photo is of it filled with putty then sanded smooth.
In preparation for painting the back panel it gets two
strips of blue tape applied that match up with the set put on the
framework. If you look closely at the
left photo, you can see where I traced the framework on the panel to guide
putting the tape on. The tape’s purpose
is to keep the wood free of any type of finish so when the two are glued
together the result is a good strong glue joint.
Mounting the double headed light bulb fixture to the back
panel is next. There was a small problem
because the fixture’s threaded mounting stud is too short to center the fixture
in the light so an extension has to be added.
Pulling a coupler and appropriate length threaded tube along with a
couple of nuts out of my lamp parts supply fixed that.
Drilling a hole in the back panel where the new extension
to the bulb fixture will go is made using the drill press to make sure the hole
is square. The threaded tube is 3/8” in
diameter and one would think that drilling a 3/8” hole would work just fine but
that’s not the case. The 3/8” tube is
really .381” not .375” or about .006” oversize.
Also, a 3/8” bit does not really make a 3/8” hole when drilling in wood
due to the fiber compression during drilling and spring-back after
drilling. The hole made is actually
.008” undersized. End result is the
threaded tube won’t fit. What does work
is to use a 10mm bit that makes a 9.8mm or .386 hole which is about .005”
oversize.
The frame will be glued and screwed to the back panel and
the process to locate and drill the screw holes takes a few steps. It starts by drilling four small holes from
the face of the back panel centered on the blue tape. The red arrows point to their locations.
Next is to set the framework on the back panel and align
it in its final location then clamp the two parts tightly together. The clamped assembly is then flipped over so
the back side of the back panel is up exposing the just drilled four holes (red
arrows). That’s been done in the top
photo. Next using those four holes as
guides a pilot hole is drilled into the back of the framework’s post. The tape on the drill is used as a depth
gauge for the hole depth.
Last is to add a countersink to the holes so the screws
set flush with the back side of the back panel.
The bottom photo is a closer view of the counter sink drill and what the
resulting hole looks like. As an aside
the panel looks a little rough but that’s because it’s been primed and sanded
smooth getting ready for the top coat.
Doing a test assembly where the bulb fixture is installed
and the framework is attached to the back panel with screws that are installed
using the just drilled and counter sunk holes looks like this. 
Next Up – Installing Switches, Cutting Lenses & Final Assembly
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