I started on the top by ripping the number 2 board of the
first half to it’s final width plus a sixteenth inch then clamped the first
board to it to make sure the glue joint will be tight and the boards will lay
flat. With a tight and flat joint I made
the final trim of the number 2 board to width.
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| Board #1 & #2 Clamped Together |
With that done I use the sliding miter saw to cut a clean
square edge at each end of all the pieces.
To help keep the glue joint faces flush with each other I
will use biscuits. These are not baking
powder biscuits that are good with gravy but rather oval pieces of compressed
wood that fit in matching slots. The cut
is made with a biscuit joiner which uses a small circular saw blade to cut a
crescent-shaped hole in the opposite edges of two pieces of wood.
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| Biscuit Cutter & Biscuit |
The biscuit joiner is set to center the cut in ¾”
material. My top is going to end up
between 1” and 1 1/8” thick and I want the biscuit pretty much in the
center. The tool has a secondary
adjustable fence to set this height but it works by registering the cut from
the top instead of the bottom. In
testing I found this fence had some play in it.
It could cut slots not perfectly 90 degrees to the glue joint, at
slightly different heights or both. What
this means is when I go to glue everything up the misalignment could cause me
problems. My solution is to not use the
secondary fence but to simply add a 1/8” thick spacer made out of Masonite
under tool thus raising the center of the cut so it is centered on a 1” thick
top.
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| Biscuit Cutter with Blade Exposed & Resulting Cut |
To make the actual cuts I clamped the board down tight to
the workbench. This is critical since
the biscuit cutter references off the bottom so if the bottom of the board and
the bottom of the biscuit cutter is not tight to the workbench any gap will
result in that much of an offset when you go to join the two boards.
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| Biscuit Cuts in Test Piece |
In the photos below the pieces I am joining are left over
tests from when I was surfacing the top pieces down. In the top photo you can see the two biscuits
set partially down in the cut and in the bottom one where I drove the pieces
together. The biscuits held the two
pieces in alignment giving me a precise smooth joint between them.
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| Biscuit Test Fit |
Next using a scrap piece of oak as a story stick I laid
out the locations where I wanted to install the biscuits. Now all I have to do is align its end with
the edge of the top and mark the locations.
Since there will be 10 sets of joints this will speed up the layout plus
making it more consistent.
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| Story Stick for Marking Biscuit Locations |
With the biscuits laid out I can clamp the first top
piece in place and start cutting it’s biscuit slots then move on to the second
piece.
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| Production Biscuit Cutting |
When both pieces have the biscuit slots cut I can do a
test fit. Here is the part of the first piece set in
the clamps with the biscuits in place.
Next is to add the second piece, tighten down the clamps, check where
the two pieces come together for gaps and make sure the faces are flush. Last, I lay a straight edge across the joint
to check to see if both pieces are flat and in the same plane. If everything checks out I am ready to
unclamp the pieces, remove the biscuits and glue the two boards together.
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| Biscuit Test Fit |
As is normal it seems like a race against time when doing
a glue-up. In this case I need to put
glue in the biscuit slots, then on the first piece edge and last on the upper half
of the biscuits where they will go into the second piece. One thing that adds to the tension is that
when the biscuits come in contact with the glue they start to expand. On one
hand this is good as they lock both pieces together. On the other if you are too slow they can
expand so much it’s tough to force them into the slot and get the two pieces of
the top pulled tightly together so you end up with a gap free joint. When it goes well and the clamps are
tightened you get a flush joint, a flat surface and no indication of the biscuits.
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| First Two Board Glue-up |
After letting the glue cure overnight, I take off the
clamps and check the results. Everything
is within tolerances so I can now go through the process to add the third
board.
- Test clamp to make sure glue line will have no gaps and correct as needed.
- Rip to width plus a sixteenth inch
- Cut ends square
- Layout biscuit locations and cut
- Test clamp with biscuits checking face alignment and flatness
- Glue-up
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| Completed 3 Board Glue-up |
After letting the glue cure overnight, I took off the
clamps and checked the results.
Everything was good so I could set it aside and go through the whole
process three more times. The plan was
to glue-up two of the 3-board sections to create one of the two pieces that
will make up the top. As with other
parts of this project the plans changed.
When I got done with the 3-board glue-up it felt heavy. That was confirmed when I put it on the scale
and it showed 25 pounds. Gluing two of
them together as I had planned would have yielded a 50-pound leaf. Imagine taking a 32” x 52” table leaf that
weighs 50 pounds on and off, maybe not the best plan. Four 16” X 52” leaves at 25 pounds each
sounds better. When I increased the top
thickness 50% from ¾” to 1 1/8” I also increased the weight by 50%. DUH!
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| All 4 Leaves Set In-palce |
With all four sections glued up I sat them on the table
to get an idea of what it will look like.
I think the extra thickness is good visually.
Next Up – Flattening & Sizing the Leaves, Making the
Pegs
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