PORTSMOUTH — To survive long enough to celebrate a 125th birthday, you must be doing something right, particularly if you’re a business … and a manufacturing business to boot.

Chadwick & Trefethen Inc. is doing just that for the precise reason that it’s been doing something right for the past 125 years as a manufacturing business in Portsmouth.

It makes reamers – a tool for widening or finishing drilled holes.

“We pride ourselves in making a quality reamer,” said David Richards, the company’s president whose grandfather’s uncle started the business with a machine shop in 1892. “You do a job, and you do it right the first time.”

The company celebrated its big anniversary with an open house on June 30 that attracted several dozen employees, family, friends, former employees, and customers.

It is located at 50 Borthwick Ave., in what is now the bustling commercial area of medical offices, Portsmouth Regional Hospital, Liberty Mutual, Northeast Credit Union, office condos, and High Liner Foods.

Chadwick & Trefethen was the first occupant of the burgeoning Orchard Park back in 1964, after it moved from its original location on Bow Street to make way for the federal government’s McIntyre Building.

The company’s history, as related by Richards and Dave Bovee, the company vice president, G.B. Chadwick originally worked for the Portsmouth Machine Co., where its superintendent, John Critchley, invented an adjustable mandrel, a forerunner to the reamer.

“It would have been a pretty natural progression of things to sharpen those blades, and make it into a cutting tool, aka reamer,” said Bovee.

Chadwick, at age 34, in 1892, opened his own machine shop on Bow Street, having acquired the patent rights to Critchley’s tool.

“By all accounts, Chadwick was a clever and creative guy, and in the early years they tackled a wide variety of projects, bicycles, pipe-fitting, and electrical work among them. Eventually, though, they mainly focused on manufacturing reamers of various types, as we do today,” said Bovee.

With the development of the McIntyre Building, the government bought the land in Orchard Park for Chadwick & Trefethen to move, while the company had to finance the construction of its new manufacturing facility.

While there are many types of reamers made and sold by Chadwick & Trefethen – angle blade reamers, ball joint taper reamers, valve stem reamers, to name just a few – the Critchley adjustable blade reamer remains its major product.

Different types of steel are used in the manufacture of the adjustable blade reamer’s different sections – the body, two adjustable nuts, and the blades. The parts fit together in precisely ground tapered slots.

“We’ve been making the same product this whole time,” said Richards. “Our sales are mostly geared toward repair work.”

The business, said Richards, was very active starting in the 1920s with the Industrial Age and the manufacture of automobiles. Before automation, robotics and computer numerical control (CNC) machining, motors and car parts were handmade with reamers in demand for the work.

Six full timers work at Chadwick & Trefethen, which continues to be family operated. In addition to Richards as president, there is his sister Carol Bovee, who is the office manager and his brother-in-law Bovee, who is vice president and production manager.

Richards said he owes the longevity of the company to the business practices of those who preceded him.

“The generation that came before us were pretty smart people,” he said. “You treat customers and employees right, you pay your bills on time.”