My benchtop is glued up oak flooring, set vertically so the edges face up. I
am attached a 8/4 apron all the way around, using sunken carriage bolts to
secure versus glue. I have looked at a lot of solutions, but most assume you
do not have the top enclosed within another frame. Securing only one side or
only the middle of the edge to breadboard end does't seem to be an option.
Question: How do I allow for expasion of the core table top in this
scenario, or should I not worry about, given the individual slats are only
about 1" thick by 2.5" wide?
Respectfully... No. The cell of a tree is like a toothpick. When hydrated,
it will swell in girth but not length. If the bench is oriented North/South
it will expand and contract both east/west and up/down.
To answer the original poster: Don't attach the apron pieces to each other,
and lap them (no miter). That is let them just slide past one another. Glue
the front and back aprons; bolt the sides. Install one bolt tightly on each
end cap. Other bolts should have a sloppy hole to allow movement.
Imperical data: I have gotten through almost 1 full year with a 3"x24"
lamidated maple top. Casual inspection show about 1/8" (at the most) in the
24" dimmenson summer to winter. With the tight bolt centered, that's <1/16
to account for at the corners. It's quite small.
Proportionally, I think it's about the same. That is a 1x6 will expand more
in width, just because it's 6 and not 1.
As an asside, people here have suggested that that quatersawn boards are
more stable. That's a bit misleading. Since interior parts of a tree are
generally more dense than the newer growth, this will cause uneven changes
in two sides of a board, resullting in cupping of a flatsawn board.
By contrast, a q/s board will expand and contract as much as a flat sawn
board, but it will do so (more) evenly with respect to both surfaces, and
will be less likely to cup. It will still expand and contract with humidity
Wood expansion/contraction is measured in 3 directions -
0 Radial ie. sort of across growth rings along radisu from center of
tree as for example across quarter sawn board
o tangential to the growth rings as for example across a flat sawn
o longitudinal - along the grain
Greatest movement occurs tangentially with the radial movement
generally on the order of 30-50% of tangential and almost
negligible(fro most cases) along the length.
So, as indicated below, movement across the workbench top cannot be
If you are interested in precise details see table 12-5 of following
v. useful reference
On Wed, 7 Jan 2004 11:16:49 -0500, "Anthony Diodati"
That sounds good, except I was hoping to do a nice dovetail or boxjoint on
the front corners of the apron. Would it work to do the front with
dovetails, and leave the back joints simply buted without glue, allowing for
the movement you indicated? I would bolt the front aprons, attach the
breadboards as you described, and the back as I indicated? Would that work?
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