Save yourself some dollars and make splines out of hardboard
[Masonite]. It's cheap, cuts easily [wear a mask - it's dusty], and is
more than adequate for the job. The main function of the splines is to
keep the boards in alignment. If the ends of the boards will show,
i.e., no breadboard ends, make sure you stop the grooves at least one
inch before where the finished end will be. If you decide on a
breadboard end, don't glue it on. Lateral expansion of the field boards
will tear it apart. That's a subject for another thread.
Save the expensive Gorilla Glue for a project where you really need
that much performance. Titebond-II is more than enough for this table.
Spend a little money on a carbide slot cutter bit with a 1/4 inch thick
cutter [the same thickness as the hardboard]. Take the router out of
the table - this job will come out better if the router is handheld,
because if the boards have any curve, and if you run them across the
table with the convex side up, the bit will not stay centered on
thickness of the stock.
Spend some time - a lot of time - arranging the boards before making
any grooves. A lot of people talk about alternating the growth rings,
but I think it is even more important to orient the grain. Look at the
edge of each board to see which way the grain slopes up to the face. If
you keep all of the grain sloping the same way it will be much easier
to plane the top after glue up. To prove this to yourself, clamp two
scrap boards side-by-side with alternate grain slopes, and plane the
face over the joint. One face will plane smoothly and the other will
tear out. Guess how I learned this.
Once the boards are laid out, mark all of the faces with chalk, and
make a big chalk triangle to help with re-assembly. Make sure that you
rout each board with the face up, towards the router, so that any
variation in board thickness will fall on the underside of the
Go easy on the glue. I small bead of squeeze-out confirms the proper
amount. Practice on scrap.
If you use black pipe clamps, keep them away from the wood and the
glue. Waxed paper works well.
Clamp up the assembly dry before you reach for the glue. You don't want
to find out that you don't have enough of the right sized clamps while
your glue is setting up. I'd recommend clamping long scraps along the
faces to keep the assembly from curving. Put waxed paper under them so
they don't become part of the table.
Scraping off as much of the glue bead as you can reach when it gets
tacky - about 20-30 minutes after clamping, will save you some work
Take your time, especially with planning. The table might be aound for