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Ironwood Designs, a manufacturer of
wooden gun stocks, has increased production 200 to 300 percent after
replacing a manual pantograph with a four-axis Techno CNC router.
Previously, the company used the pantograph to carve out inlets and
other areas in the gun stocks. It was a back-breaking process that
was both slow and inaccurate. The four-axis CNC machine can carve
the cutouts in about one-fifth the time it took to do them by hand.
And since the machine can automatically reposition a part and cut
all sides in one operation, it can run unattended. This lets one
employee to do the work of two. In addition to being faster, the CNC
is much more accurate than hand carving, giving Ironwood Designs a
reputation for quality work. “The Techno machine has boosted the
volume of our business by letting us take on jobs we didn’t have
time for, or couldn’t do accurately enough in the past,” says Matt
Shuster, President of Ironwood Designs.
Ironwood Designs, located in San Jose,
California, designs and manufactures replacement gun stocks. The
company’s products, made of high-quality hardwoods, are purchased by
individual gun owners, gun dealers, and firearms manufacturers to
replace the inexpensive plastic or softwood stocks of many imported
military guns such as the FN-FAL and the AK-47. Ironwood Designs
sells a four-piece wooden set that includes the butt stock, pistol
grip, and an upper and lower hand guard. As one of the few companies
making replacement gun stocks for these weapons, Ironwood Designs
has a thriving business. The company’s previous production process
had a bottleneck, however, that needed to be eliminated so they
could grow.
Keeping up with Business
In the first step of making a gun stock,
a Zuckerman copy lathe is used to automatically carve a wood block
into the desired 3D profile. A Zuckerman machine is the gold
standard in the industry for profiling; it is the same machine that
shapes the necks of Fender guitars.
This part of the production process,
which was handled by an Ironwood Designs employee, needed no
improvement. The next step was the problem. After parts are cut on
the Zuckerman machine, they need further cutting to carve out the
inlets where the stock fits into the rifle and areas where parts
such as the swivel and the butt plate are later attached to the
stock. After running the parts through the copy lathe, which was
located in the company’s shop, Shuster took them to his home
workshop where he used a manual pantograph to make these additional
cuts. The pantograph had four spindles so four parts were cut at
once.
One problem with this approach was the
sheer physical labor involved. Shuster did this work himself. It
took an average of 15 minutes to complete the carving process for
four butt stocks. If Shuster’s hand slipped, four parts were damaged
at once. He estimates that he had a loss of between 10 and 15
percent due to carving error.
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One step of the process in creating a
wooden gun stock.
A desire for a faster, more accurate
carving process led Shuster to look at other options besides the
pantograph. He had researched the technology and knew that a CNC
machine could be programmed to automatically cut the shapes he was
then cutting by hand. One option was to purchase a heavy and
expensive CNC machining center primarily designed for metalworking
and adapt it for working with wood. He had heard of other
woodworking companies doing this, but the $125,000 to $250,000 price
tag of these machines was prohibitive.
At a woodworker’s trade show, Shuster
found a better alternative, a four-axis CNC router machine from
Techno Inc., New Hyde Park, New York, designed for production
routing and drilling on a wide variety of materials including wood,
plastic, MDF, solid surfacing materials, and nonferrous metals. This
machine’s complete system was affordable; it has two 5 HP Colombo
spindles with dual rotary stations for high production, and can cut
two identical parts at the same time. Shuster also appreciated its
robustness, which included steel stress-relieved bases with hardened
steel linear ways, ball screws, and servomotors as standard features
for precision performance, speed capacity, and machine longevity. He
purchased a Techno four-axis machine with a five by six feet table
big enough to handle even the longest butt stocks.
Four-axis Benefits
The four-axis capability of the Techno
machine is what makes it the solution Shuster was hoping for. If he
had purchased a traditional, three-axis CNC router, it would have
been necessary to continually reposition parts on the machine
because cuts are needed on all sides. Although this still would have
been faster than cutting parts by hand, the machine would have
required constant attention. A four-axis machine, on the other hand,
has dual spindles, one that holds the part and one that holds the
cutter. The cutting program directs the x, y, and z motions of the
cutter, as with a traditional CNC machine. But it also directs the
positioning of the part. After one side has been cut, the part can
be rotated, for instance, to allow access to the other side. “With a
four-axis machine, repositioning happens automatically so the
cutting goes faster and it’s completely unattended,” Shuster says.
Using the four-axis machine, it now takes Ironwood Designs only
three minutes to cut four butt stocks, compared to 15 minutes needed
with the pantograph.
Shuster estimates that the overall
productivity of his business has increased by 60 to 80 percent since
he acquired the CNC machine. |
It is located in the shop with the
Zuckerman copy lathe, and one employee runs both machines. Shuster
handles light finishing work. “We now produce 100 pieces in four
hours. Previously that took us two days,” he says.
The quality of the cuts is much better
with the Techno CNC machine. “There is less tearing of the wood
because spindle is spinning at 18,000 rpm,” says Shuster. “And if a
cut is off by 0.010 inch, I can modify the NC program and easily fix
it.” In the past, the tightest tolerance he could achieve was 0.01
inch to 0.02 inch. The Techno CNC machine holds between 0.003 inch
and 0.004 inch. “That is phenomenal for wood,” says Shuster. “Now we
produce factory quality pieces. You can’t distinguish our stocks
from the original military production except that we use a higher
grade of wood.”
The combination of higher quality and
faster production has led to an increase in business for the
company. After finishing a large, two-and-a-half year contract for
one gun manufacturer, Shuster has now programmed the CNC machine for
a new product, a replacement stock for the Belgian FN-FAL rifle.
Designed in the 1950s, this rifle has been out of production for
years. But surplus versions are being imported, and new ones are
being manufactured in the US from old military specifications.
Ironwood Designs is now offering replacement parts for this rifle to
manufacturers, who will resell them as accessories, as well as to
smaller gunsmiths who build FN-FALs for customers, and to individual
owners of the rifle who wish to retrofit it with a nicer wooden
stock.
In addition to this new product, for
which Shuster anticipates a big demand, he plans to use the Techno
CNC machine to take on projects he has long wanted to do but
couldn’t in the past because of time or accuracy limitations. For
example, he plans to offer replacement stocks for common guns such
as hunting rifles that are far more easier to install than those
that are currently available. Most replacement stocks come
semifinished. The sides are carved but they have not been sanded so
tool marks are visible. The gun owner has to fit the rifle to the
stock, a process than can take hours of filing. For those who aren’t
experienced woodworkers, there’s the danger of damaging the stock.
Shuster plans to cut these stocks on the CNC machine for a level of
accuracy that has been previously unavailable. “My kits will be
innovative because they give you drop-in fit,” he says
The acquisition of a four-axis CNC
router improved productivity and accuracy at Ironwood Designs. The
result is an increase in business. “We no longer advertise and yet
our volume keeps increasing,” says Shuster. “With a four-axis Techno
CNC machine, we’re now able to produce replacement stocks for anyone
who wants one.”
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