While this is neither an original nor a unique idea, it is a great
solution. Besides cutting down on the number of required clamps, it
reduces the need for diagonal measurements, saves time and vitually
guarantees perfect 90deg corners.
As you can see from the following picture, construction is pretty
simple. It has a base of very flat plywood. Two fences, fixed
permanently to the base at a perfect right angle, provided the clamping
reference. I used a scrap of baltic birch plywood, because it is
typically higher grade than construction grade plywood - and having a
very flat surface is paramount to building a useful fixture. Other
scraps of the same plywood were used as the sides. If you will only use
the fixture for short items, such as picture frames, a single 3/4"
piece for the fence would be adequate. I made mine 1.5" high, to give
me more freedom in placement of the clamps. Using my best reference
square, I glued and clamped the fences in place and drove a handful of
countersunk screws into the fences from below.
|I recommend beveling
the lower, inside of the fences. This will prevent dust and debris from
building up against the fences and reducing the accuracy of the fixture.
I also left the inside corner of the fences open for the same
reason. Additionally, this allows any glue squeeze-out from a
mitered corner to be removed easily...without glueing the workpiece to
To minimize any deflection of the fixture due to moisture changes, I
sealed the entire fixture with a coat of shellac. Afterwards, a coat of
wax on all the fixture surfaces will help prevent glue from sticking to
the fences or base.