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Jesada Tools - products of a quest for excellence

Welcome to our tour of Jesada Manufacturing, the state-of-the art facility that produces Jesada's beautiful white-coated router bits.

Making the finest router bits requires a careful blend of high standards, highly-skilled people and high technology. Some steps in the process can be almost completely automated, others are dependent to a great degree on the care and skill of a well-trained staff.

Computer screenAny tour of this facility should begin at the desk of one of Jesada's bit designers. On the screen before us is a three-dimensional view of a cove bit. This carefully-drawn outline seems simple enough, but it is the framework upon which the entire production process will hinge. From this drawing computer programs will be developed to control several key machines. An error here and the plant will produce a chunk of useless steel instead of a precise Jesada bit.

The first machines to be programmed are the turning centers, which are actually huge automated lathes. A special computer program allows the designers to take the drawing of the cove bit and calculate the sequence of cuts the lathes must make to cut, or "turn" the bit body. As we watch the computer screen the path of each tool appears in overlapping multicolored lines.

Once the designer is sure the tools will do exactly the right job, his on-screen simulation is converted into a code that can be read by the lathes. Later he'll create similar programs for computerized milling machines and the huge five-axis grinders.

Now that we've been introduced to the design process, let's step into the factory for a taste of real bit production.

On our way to the big turning centers we pass a rack full of Fatigue-Proof™ steel bars. Jesada bits aren't made from castings! They are turned from solid steel bars. That's important, because it's been my experience that turned bits offer a superb combination of balance and strength.

We're at the Turning Centers now, and they really are fun to watch. Truly state-of-the-art machines, these tools can turn the body of a bit with a tolerance of .0002" (two ten-thousandths!). That's about 1/10 the thickness of a sheet of paper!

As 12'-long steel bars are automatically fed into the machine, the computer program we discussed earlier goes into action. We watch through a small window as first one tool and then another peels off long spiral-shaped layers of steel under a flood of coolant, In a matter of seconds the shape of our cove bit appear in bright, shiny steel. We also see a drill and tap take their turns preparing for the bearing screw.

Next stop for our bit is one of the Milling Centers. The designers have created computer codes for these machines that tell them exactly how to cut the gullets (vertical grooves) in the bit body. The shape and location of the gullets is crucial to the placement of the carbide tips.

Next the freshly-milled bits are placed in stainless steel baskets and dipped in a 160° bath of distilled water and an alkaline solution. This step is important because any oil, coolant or other residue from the milling process could contaminate the braze.

Now we arrive at the Brazing station, where our bit body becomes a full-fledged carbide tipped bit. The bits are clamped in a special vise one at a time. A wire coil loops around the body of the bit. In a process called induction, radio waves heat the body to a dull red. Induction brazing gives Jesada excellent temperature control. That's important, because too much heat can make the carbide and steel brittle. Now the technician positions each tip and brazes it in place using a special alloy with a high silver content.

After careful inspection at the brazing station and sandblasting to remove brazing residues, the bit is ready for the application of the white PTFE (poly-tetraflouroethylene) coating. PTFE may not be a household term, but if you've ever fried eggs in a non-stick pan you've used it. Our bit joins several others in a special spray booth where the bits are thoroughly coated with liquid PTFE, then they are placed in an oven and baked at temperatures of 500°F. The result is a tough, almost-indestructible white shell on the body of each bit.

After it cools our bit is ready for grinding, which is the true "finishing touch" of the process. First comes the centerless grinder, a behemoth that delicately polishes the shank to a tolerance of .0004" (four ten-thousandths).

Walters five-axis grinder center
Walters Five Axis Grinding Center

Now the bit arrives at the pride of the Jesada plant: the big Walters five-axis grinders. As the first manufacturer to use these fascinating machines for router bit production, Jesada has achieved a quality of finish on the carbide that is unmatched in the industry.

A computer monitor on each grinder provides a precise visual display of the entire grinding process. As we watch through the grinder's clear glass shield we see our bit virtually disappear in a flood of coolant. Once the process starts no human action is needed, the programming guides the grinding wheels through the entire process. What emerges from the grinding centers is a sharp, perfectly-formed bit with carbide that truly gleams like a mirror.

Now the bit is ready for a very demanding series of inspections. Bits are studied on an optical comparator, which compares the profile to a template projected on a large screen. Then it is studied under a magnifying lens and bright lights. Only if it clears those hurdles (and we see bits rejected for the tiniest imperfections) is Jesada's trademark logo etched on the shank.

Bit stages of manufacture
Four key steps in bit production. From left: (A) the freshly turned bit, (B) gullets are milled, (C) carbide tips in place and sandblasted. (D) ground, coated & finished!

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