A team of five graduating University of Idaho mechanical engineering students has designed safety-and-efficiency improvements for a machine used to assemble flagship folding knives that helped make Buck Knives a household name.

For their senior—or capstone—project, the students were challenged to reduce alignment and timing problems and update safety features for an apparatus called a pin inserter machine, says Brian Bond, a member of the student team. The pin inserter is used by Post Falls-based knife maker Buck Knives Inc. to fasten the handle assembly together, while simultaneously attaching the knife blade in two of its popular models.

The student project also improves the process for switching out parts of the pin inserter, depending on which model is being produced, Bond says.

The team completed the project earlier this month when it delivered the re-engineered control system for the pin inserter two days before the students graduated from the university.

"This is our capstone design project through the University of Idaho," Bond says, a native of Vale, Ore. "It's the culmination of all of our engineering experience into one project, and wraps up our education at the university."

Gary Alvarado, Buck Knives' director of value stream operations and a former University of Idaho engineering instructor, was familiar with the engineering program's capstone projects, which present opportunities for student teams to solve real-life problems in manufacturing settings.

"One of my responsibilities with the university was to help manufacturing companies with engineering support," says Alvarado, who's been with Buck Knives for nearly a year. "Here we had a piece of equipment that was more down than up, and I thought it would be a great fit for a senior project."

Buck Knives uses the 27-year-old pin inserter to make the Buck 110 and smaller, pocket-sized Buck 112 model folding knives, two of the company's most popular and enduring models. The machine inserts three brass fastening pins, also called dowels, that hold the frame of the knife together, Bond says.

The knife maker already is benefiting from the results of the student project, Alvarado says.

Michael Thompson, lead operator for the Buck Knives group that assembles the 110 and 112 models, says that whenever the pin inserter went down, assemblers had to insert the pins by hand, slowing the entire process.

With the pin inserter working more efficiently now, it's consistently processing five knives a minute, he says.

"We probably produce twice as many knives with the machine as without it," Thompson says.

The Buck 110 Folding Hunter, with a 3.75-inch locking blade, was introduced in 1964. Among the dozens of knife models Buck Knives produces, the Buck 110 is the company's all-time top seller. In all, the company has sold 13 million Buck 110s, Alvarado says.

"The 110 has carried us for almost 50 years," Alvarado says. "It's one of our icons."

The first year that Buck Knives built 110s, the company sold 296 of them. About 20 years later, the company was building 2,000 Buck 110s a week, Alvarado says. At its Post Falls plant, Buck Knives currently assembles 700 to 1,050 Buck 110s a day.

The Buck 112, also known as the Ranger, with its 3-inch blade, is a pocket-sized version of the 110. It's also a consistent seller, Alvarado says.

Buck Knives, moved to Post Falls from Southern California in 2005, and currently employs about 280 people, says C.J. Buck, the company's CEO.

The Post Falls workforce is growing due to an upward trend in sales and the company's American Commitment initiative, which focuses on bringing production to the plant that it had been contracting out to Chinese manufacturers, Buck says.

About the time the company brought its Post Falls factory online, overseas production had been as high as 50 percent, he says. Today less than 20 percent of its production is imported.

Current sales trends underscore the significance of the engineering-student project, which is vital to enhancing production for Buck Knives mainstay knife model, Buck says of the Buck 110.

"That knife was designed by my grandfather," he says. "It's the knife most people think of when they think of Buck Knives. It put us on the map."

The company will mark its 50th year of production of the Buck 110 next year and currently is developing plans to promote the anniversary.

"We're going to spend the entire year celebrating at the top of our lungs," Buck says.

Buck is the fourth-generation manager of the family run company with roots dating back to 1902. He succeeds his father, Chuck Buck, who is the chairman of the board; his grandfather, Al Buck; and his great-grandfather, Hoyt Buck.

Multiple challenges

The pin inserter, which is about the size of a household refrigerator, weighs several hundred pounds, Bond says. The machine was manufactured by Danielson, Conn.-based Spirol International Corp., and Buck Knives has modified it extensively with custom-fabricated components, he says.

The main moving components of the pin inserter are called the upper and lower shuttles. The lower shuttle holds the knife-handle assembly and blade in place while the upper shuttle presses the dowels into predrilled holes. Two dowels secure the butt end of the knife and the third dowel, on which the blade pivots, secures the blade end of the handle.

Once the dowels are inserted, the lower shuttle slides horizontally toward the operator, who removes the knife and positions components on the shuttle for the next knife, Bond says.

One problem with the machine was that the lower shuttle moved between the operator and the insertion point with enough force to knock itself out of alignment occasionally, he says. When that would happen, the pressure the machine put on the dowels would damage other knife components.

"When it would get out of alignment, it would dig into the material," Bond says. "Then they would have to reject the knife and strip it down to salvage the parts."

Student team leader Matt Sjoren, of Hermiston, Ore., says the team addressed that problem by dampening, or slowing, the lower shuttle. A modification in the position of two bolts that attach the shuttle to the machine helps keep the insertion alignment more precise and secure.

To reduce the setup time when changing production between the 110 and 112 models, the team also modified the upper shuttle by designing a sliding tongue-and-grove mounting system, Sjoren says. The bracket holds the shuttle in alignment while freeing both of the operators' hands to install the mounting bolts to secure the shuttle.

"Before, they used to have to hold it in one hand and hunt for the bolt holes," Sjoren says. "The shuttle weighs 4 to 5 pounds. After holding it up a few minutes, it gets heavy."

The new shuttle bracket reduces stress and fatigue for the operator, as well as downtime for the machine, he says.

"The changeover that used to take 30 minutes now is down to under five minutes," Sjoren says.

Another problem with the pin inserter occurred when the machine reset for the next knife before the last knife was removed. When that happened, the assembled knife would pop off the lower shuttle, with the exposed blade posing a safety hazard for the operator. The violent ejection also could damage the knife, Sjoren says.

The student team faced that problem by installing a pneumatic delay, which eases the assembled knife off of the lower shuttle and allows the operator a few more seconds to remove it without slowing the overall pin-insertion process.

Bond says the most significant new safety feature is an added light-curtain system to help prevent hand-crush injuries as the upper and lower shuttles come together.

The system involves an infra-red beam transmitter that creates a light array. When the array is blocked by an object such as the machine operator's hand, the machine turns off, he says.

The team also redesigned the control-system electronics, and rewired it with color-coded wires.

"The entire thing originally was wired in red," Bond says. "It was kind of a nightmare."

Real-world projects

The University of Idaho's capstone program provides seniors in its mechanical engineering program the opportunity to design real-world projects to cap their undergraduate experience.

Students participating in the capstone program hear a number of pitches for potential projects and prioritize the projects they would like to work on. Their professors then select teams they think would be the best fit for each project.

The Buck Knives project team also includes Eric Sprague, of Las Vegas; Colby Nahas, of Alamo, Calif.; and Jesus De La Cruz, of Huancayo, Peru. The team was selected in September and first traveled to Post Falls to observe the pin inserter in October.

"It's the first design project the University of Idaho has done for Buck Knives," Bond says. "For us, it's a good opportunity to do a project in the manufacturing area, dealing with team dynamics, running a budget, and handling problems as they come."

Alvarado says he has always tried to impress on engineering students that they have to understand the unique needs and requirements of each customer.

"This student group did a good job with that," he says. "I'm very proud of them."