After letting the column set overnight I decided to check
and see how they matched up. Although
both had a bit of a bow in them I thought that when I clamped them up with the
bows opposing each other they would cancel out.
At least that’s the idea. To test
I pulled out an armload of clamps and set to work.
The first clamp I pulled out was one that had a rough
face. If I torque the clamp down all
those bumps will dent the maple surface which I don’t really want to
happen. The fix is simple, take some
time to put it in the vice and file the face smooth. Here are before and after shots.
With the clamp faces cleaned up I did a test run and
everything came out fine. That said I
will let the two halves set for a bit longer to make sure they are stable.
Next, I checked the pieces that will make up the baffles. Almost all of them were still flat but a
couple had developed a bit of a cup. Not
much maybe a thirty-second of an inch. I
think they are stable but will wait to glue them up for a couple more
days. I did run the edges to be glued up
through the saw to clean and square them up.
There is a method I use to cancel out any error in case the saw blade is
not exactly square with the saw table.
In the photo below the angled pencil line shows an
exaggerated example of what the edges would be if the saw blade was way out of
square and I made the cut with the top of both boards facing up. Later, when I did the glue-up I would not
have a flat piece but would get a “V” shape when the outside corners pitch up
to make the edge joint close.
The fix is to run the “A1” piece through the saw with the
top face up and piece “A2” through with the top face down. Doing that gives me cuts like the pencil
lines below. Then when glued up the error
is cancelled out and I get a nice flat plane across both boards.
The test clamp confirmed the piece was flat and because
the pieces went back together the same way they were cut apart the joint is all
but invisible.
In the drawing for the boxes I had shown just a miter as
the corner joint. Glued miter joints are
not all that strong because they are mostly an end grain joint. While the light should not be subjected to a
lot of banging around I really wanted something to reinforce the joint. There are several possibilities such as a
dovetail joint, mechanical fasteners like nails or screws, splines and
biscuits. Because I did not want to
draw attention to the joint the options were quickly narrowed down to a
couple. First, a countersunk screw where
the hole is filled with a face grain plug cut from the same piece of wood and second
using a biscuit.
I decided to made a couple sample pieces for destructive
testing. These photos are of the screwed
joint minus the plug and the biscuit reinforced joint prior to assembly.
After letting the glue cure I tried to break the joints by
hand and guess I cannot qualify as Hercules as I could not break either one
just using my hands. Putting them in the
vice and using it to really load them up got the desired results. The one with the screw failed as I expected
by pulling the screw out of the end grain.
I could have increased the strength by using a bigger longer screw or
adding a second one. The biscuit
reinforced joint required quite a bit more force to break. Looking closely at the break I could see
where the biscuit itself had broken leaving small splinters on the slot cut in
one of the pieces. Since the biscuit
joint is at least as strong as the screwed one I will use it to make the
joints. The main reason is that once
installed they will be completely invisible and for this design that is my
goal.
Now that the baffle pieces had set a while longer I did
one last clamping dry run. Three of the
sets checked out fine so I glued them up.
However, one pair just did not come together. The individual pieces had not cupped but when
clamped up there was a “V” between the outside edges joint in the center. To fix I made a bare skim cut on each joint
edge with the table saw. Re-clamping and
checking with a straight edge showed a flat surface. With that done I glued up the final baffle.
After letting the glue joints cure overnight I changed
the sanding grit in the thickness sander from 80 to 120 and flattened
them. They are still too thick at 11/32”
but being just a little paranoid I am going to let them set for a bit before
going to the final thickness.
While they set it is back to the working on the
column. In order for the wiring to be
hidden inside the column I need to cut matching dados centered in each half of
the column. Once the halves are glued
together I will have my wiring chase.
Below is a drawing showing the highlighted wire chase cuts. All the milling on the column is shown but
except for the chase they will be done later.
Note that, for now, the top cap which will go on the right end, is
missing from the column. That is because
I will be running the chase the full length of the piece and I don’t want the
top to have a ½” square hole in it. I
could have cut a stopped dado but I think it is easier and safer to make a full
length cut versus one that stops a couple of inches from the end. More details on how the cap will be attached
later on.
Next Up – Center Column, Boxes & Baffles
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