you ever felt like throwing your box joint jig out the window when,
after a long shop session, the pins and slots still don't quite
suspect Alan Schaffter has. He's had box joints "on the brain"
for years and, more specifically, the difficulty in making them
successfully with typical jigs and methods. For this retired Navy
commander and mechanical engineer, most shop-made and commercial box
joint jigs are far from shipshape. They're probably better off lying
in the yard.
found limitations with both template-based and adjustable jig styles.
"I've never been satisfied with the various box joint jigs I've
made over the years ... Good box joints rely on the spacing and size
of the cutter and indexing pins to match almost perfectly, usually
within a few thousandths of an inch ... Unfortunately, that rarely
happens." Plus, fixed-style jigs require a different template
and guide pin for each joint size, so the number of possible joint
proportions is limited by the range of templates a woodworker has.
have attempted to solve the problem of perfect fit by creating jigs
that are adjustable, but Schaffter found them lacking for other
reasons. He learned that just because a jig is adjustable doesn't
mean it can be accurately or reliably set, and the user must often
resort to calipers or making numerous test cuts to set the jig or
change the finger size.
about three years ago, while helping a fellow woodworker figure out
how to make a box joint template for a dovetail jig, Alan resolved to
give box joint jig designs more serious thought. "I just knew
there had to be an easier and more precise way to do it," he
recalls, but the 'Eureka!' moment didn't come until he clearly
understood the geometry of how all box joint jigs must work. "I
realized that even though the guide pins move different amounts,
there is a fixed relationship between the amount they move from the
cutter (dado blade or router bit). The challenge was then to figure
out a way to capitalize on that relationship."
considered a variety of mechanisms that could produce the setup
mechanics for a better jig -- common threaded rod, gears, belts,
levers, a lead screw -- but all of these would create unwanted
complexity unless it was a single assembly. This was key. He designed
a prototype utilizing a single dual-pitch lead screw with split
indexing pins that would control the entire calibration process of
the jig, "and the rest was history," he says. The "very
primitive" prototype jig worked as he hoped on both his router table and table saw, test cut after test
cut. No calipers or tweaking were required, because the jig used
direct transfer from the cutter and a workpiece instead of measuring
tools. And, the mechanics didn't depend on the precise width of the blade or router bit. It seemed clear that a better box joint jig was definitely
creating a better mousetrap doesn't necessarily make it marketable.
Alan did in-depth research on the patenting process next and learned
a number of "shockers." For one, a utility patent can cost
upwards to $20,000 or more, most of which goes to patent attorney
fees. None of those fees are refundable if the patent is denied.
Additionally, it is nearly impossible for anyone but a patent
attorney to successfully write and file a utility patent, given the
"special but arcane" patent language that's involved. Even
if it is accepted, a patent is only as good as the amount of money
the patent holder can devote to defending it. For an individual, that
alone could be a significant roadblock. Finally, few companies will
buy a patented design outright, due to high upfront costs and
things considered, getting a utility patent for his new box joint jig
was out of the question. Equally unfeasible was trying to manufacture
and market the jig himself, Schaffter resolved. The best solution was
to file a Provisional Patent Application, which allows an inventor to
use the term "patent pending" and establishes a date marker
for a design, then seek a manufacturer with whom to license the
license...is a vehicle to receive money for your design from a
company who you license to produce it," Alan says. But licensing
has its price. Since the manufacturer takes all the risk and funds
both the development and marketing of the design, the licensing fee
to the designer is typically very small, ranging from one to five
percent of the wholesale cost of the product. "Unless you invent
an item with wide appeal beyond woodworking that has high volume
sales, like an iPad or iPod, you are not going to get rich from a
Provisional Patent Application in hand, Alan contacted a half dozen
woodworking accessory manufacturers and described his new box joint
jig, offering to license it. All of them showed interest, he recalls,
but it was Chris Taylor of Taylor Design Group and INCRA®
Precision Tools that
stepped up to the plate to license the basic concept and mechanism of
Schaffter's design. Once the details were finalized, serious
development began in 2009.
the three years that have followed, INCRA and Alan exchanged more
than 900 emails of engineering drawings, sketches, photos and
analysis, in order to bring the INCRA I-Box jig to fruition and now,
to market. Alan remained contractually involved throughout the
process, without compensation, to consult and experiment with the
evolving design. He says that his pre-production prototype now has
"more holes than Swiss cheese," after using it extensively
for beta testing.
generated CAD designs for the extrusion profiles and other parts of
the jig, as well as specs for parts suppliers. Their fabrication
expertise helped to keep manufacturing costs down. INCRA also
suggested the addition of micro-adjustment, which Alan devised and
the company incorporated into the jig. Schaffter admits that it was
Taylor's wife Alice who came up with the name "INCRA I-Box,"
which stands for "Intelligent Box Joint Jig."
entire process proved to be a collective effort.
this jig would never have been built without my initial functional
discoveries and concept ... but the jig as described in my initial
drawings, specifications and prototypes was a long way from anything
remotely manufacturable or marketable. Chris Taylor and the folks at
INCRA Tools really brought it all together and made it what it is
today ... Without (those) efforts, it never would have seen the light
far, it seems woodworkers who are using the new I-Box are reaping the
benefits from the partnership and sweat equity that has gone into
this new jig. Schaffter says that among more than six online forums
he monitors, or in any magazine, there have been no negative reviews
of the jig's performance. The response has been "overwhelmingly
While Alan's experience is proving to have a fruitful outcome, he has a few words of advice to offer. For
those readers who might have a novel design for a new woodworking
widget, Schaffter first recommends a reality check. "Be honest
with yourself and ask: is it really needed? Are there other similar
devices on the market and, if so, is yours that much better? How and
why can it be manufactured easily, economically and profitably, or
will people just make DIY copies of it?"
you're still convinced you've got a winner, make the best possible
prototype you can to verify that your idea actually works, and do
your CAD drawings. Learn all you can about non-disclosure agreements,
patents and licensing. Evaluate the market, in terms of manufacturers
who might want your design and who would be willing to fit it into
their product line.
other words, well-intended inventors, take the advice of a former
naval commander who now knows how to navigate the choppy waters of product design: Do your homework.