Before I start the multi-step process drilling all the
mounting holes for the slats a little more layout is required on the seat/back
braces. A center line the length of the
braces gets added and last a center line where the slats go gets added. Rather than measure each slat center line a
compass is set for the correct distance and used for marking. The intersection of those two will be where
the screw holes will get drilled.
Below is a section longways through the seat brace. It shows how the holes are angled so the
screws will be square with the slats shown in blue. Note that the second hole does not have a
screw. That’s because a hole there would
exit where one of the two main horizontal supports go. This means it’s going to be pretty hard to
get to the screw if that slat needs to be replaced. There is a solution and I’ll explain that
later. For now, since the top of the
brace is the only place where the holes are located that has to be the starting
point.
It all starts by using the center finder in the drill
press to adjust the fence so the holes will be dead center in the brace. At this time, I am not worried about the
left/right alignment but just the front/back alignment.
Here is the setup on the drill press for a typical
hole. The angle of the brace has to be
adjusted so the centerline of the bit aligns with the centerline of the
hole. This means that every hole except
for a few along the back requires a different setup. To make sure that angle is correct the wood
block in front of the brace is used as a reference while the wedge is adjusted
until the centerline of the hole is parallel with the block’s edge.
These two photos show different setups on the drill press
so the drill is parallel with the screw hole’s drawn centerline. In the left photo you can see how the block
is aligned with the brace’s line while the right photo shows the setup of those holes that are square with the brace. 
In trying to drill the hole where the seat and back meet I ran into a problem with a part of the drill press hitting the edge of the seat brace. To get around this the fence needed to be skewed at an angle while keeping the bit centered.
One problem with drilling this first set of holes is that
the drill is not long enough to go through about half of the holes. The top photo shows the maximum depth I can
drill. This is a problem since the
countersink for the screws needs to be drilled from the bottom of the piece and
I don’t know exactly where that is without a hole drilled completely through
the brace. The fix is to use a longer
drill bit shown in the bottom photo to finish drilling the hole. I did not use the long bit in the drill press
because it is fairly flexible and could wander off-center.
Now that there is a starting point on the side opposite
where the slats will go (bottom) the countersink can be drilled. Because the screws being used shown in the
left photo have a flat bearing face the countersink needs to have a flat bottom
which is made with a special bit. The
bits used to make the countersink are the four in the right photo. The three on the left are used to gradually
increase the pilot hole to its final diameter.
The tape on them gives me a depth that’s just short of the final
countersink depth. Graduated bits are
used because there is less of a chance of the bit wandering off axis with
incremental increases in diameter versus going to the final size in one
step. The fourth bit is a stepped bit
with the end the same size as the pilot hole and the larger body made to drill
the flat bottom hole needed.
To drill the countersink hole, the seat/back brace is
clamped in the vice so the center line of the hole to be drilled is vertical,
in this case it’s the one on the far left as shown in the top photo. The bottom photo shows the completed hole
with the step bit in the drill.
Last is to put a screw in and check to see if it sticks
out the correct amount. Just to be safe
the stepped drill is initially set a little shallow so most often a small
adjustment is needed. Drilling all the
countersinks is not hard but there is just a lot of bit changes since at least
half the holes have a different depth countersink so many different setups are
needed.
Once all the holes have been drilled and it did take a
long time what with all the different setups required it’s time to address the
one hole that would have come through at the main brace. Using the pocket-hole method while not what I
wanted to use for all the slat attachments will work here. This photo shows the jig clamped into place.
In this case a single pocket-hole doesn’t look too bad
and will provide access to the slats screw.
One would think that there’s enough holes in the
seat/back braces but not quite. There is
an even dozen more holes to be drilled.
Half are used to attach the back cap and the other half are for the
front cap. Here is where those two
pieces go.
They are also going to be attached with
pocket-holes. This is the setup used to
drill the ones in the seat/back brace for the top cap. The holes for the front cap are done the same
way. 
Finally with all the holes drilled the next step is to
route a small radius on the back and bottom edges of the three braces. Once that’s done the three braces are ready
to be used in a test fitting of the slats.
Clamping the braces to the workbench holds them stable
while I set some slats in place to see how it will look. Now some of them have a bit of a curve in but
I am sure that they can be pulled into place and held there.
Next Up – Installing the Slats, Roughing out Parts &
Fitting the Arms
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