He’s a Factory Owner and Friends With Trump. That Makes Tariffs Personal.

Still, he feels an obligation to keep his factory running. Some of Harper’s employees have worked for him for decades. He has watched them buy houses and put their children through college.

“It’s kind of a personal thing,” said Ruffin, who grew up in Wichita and still visits every week or so.

Harper employs about 120 people. On a mid-December day, the roughly 400,000 square-foot factory is chilly. The breakroom is filled with holiday decorations, and the staff is looking forward to a Christmas lunch the next day catered by Stroud’s, a local restaurant known for its fried chicken.

Some workers arrive at the factory each day around 3 a.m., a schedule they adopted to deal with intense heat in the summertime. Signs throughout the factory are written in English, Spanish and Vietnamese.

Workers use machines to shape steel and aluminum into the components of the hand trucks. The pieces make their way through welding, painting and assembly, then are packaged for shipping. Products leave the factory with red, white and blue stickers saying “Made in the USA with pride.”

Domestic manufacturers remained the largest supplier of hand trucks to the U.S. through 2014, according to U.S. International Trade Commission reviews. But by 2019, imports from countries outside of China, primarily Vietnam and Taiwan, overtook domestic producers in market share.

In recent years, Vietnam emerged as a major winner in Trump’s first trade war, becoming a magnet for Chinese manufacturers looking to get around tariffs. That explains why the bosses at Harper are cautiously optimistic about Trump’s proposal to add tariffs on all imports.

“I would take a tariff on Vietnam if it made the playing field equal,” said Harper’s senior vice president and general manager, Chris Squires. A mug in his office reads, “Don’t blame me I voted for Trump.”

He doesn’t think a 10% tax on imports from Vietnam is likely to move the needle. But a 20% tariff might make Harper more appealing to the retailers that buy hand trucks.

Harper recently lost a contract with Lowe’s, which Ruffin attributed to a shift toward cheaper models imported from Vietnam. Lowe’s didn’t respond to a request for comment. Overall in 2024, Harper sold about 290,000 units, down from around 410,000 units in 2023 and about 560,000 the year before.

Advocates of tariffs say duties can help bolster U.S. industries, respond to other countries’ trade practices and bring in revenue for the government. They say tariffs can help make the U.S. economy less reliant on other countries.

A U.S. International Trade Commission report found that Trump’s 2018 tariffs on steel and aluminum reduced imports, increased U.S. production of those products and were followed by the announcement of new domestic investments by steel and aluminum companies.

The same report found that production fell for downstream manufacturers that use steel and aluminum. Some studies found that higher costs for parts and retaliatory tariffs hurt domestic producers, outweighing the benefits of tariffs to other parts of the manufacturing industry.

“I worry about the unintended consequences,” said Mike Rose, Harper’s controller.

Harper imports wheels and casters from China and buys other pieces of small hardware sourced abroad, so it anticipates those costs to go up if tariffs increase. It is in the process of switching some of its wheel purchases to a U.S. maker, but doesn’t expect to be able to source all of its parts domestically.

It also bought a Chinese manufacturer called WelCom Products in 2013 that produces lower-end folding carts, which make up a smaller portion of the company’s sales. Squires, the general manager, expects that higher tariffs on China would significantly curb that line of business for Harper.

Harper raised prices when tariffs from Trump’s first term increased costs, and is prepared to do so again to meet its target profit margin if Trump lifts tariffs further. One model that can carry 600 pounds sells for around $80 at Home Depot. Another model that can be converted into a four-wheel cart goes for about $130 at Walmart.

Some economists say increased trade with the world has helped lower costs for American consumers and has allowed U.S. businesses to offload lower-skilled production overseas, while focusing on research, innovation, design and marketing domestically.

U.S. manufacturing employment peaked nationally in 1979 at nearly 20 million workers, representing 22% of nonfarm employment, according to Labor Department data. As of November, roughly 13 million people were employed in manufacturing, about 8% of nonfarm workers.

“Do we want to be using resources to redirect workers and capital towards a job that can be done equally well by a low-skilled worker in Vietnam?” said Teresa Fort, a professor at Dartmouth College’s Tuck School of Business. “We have to ask, how much more expensive are we willing for our goods to be in order to have those jobs back?”

Even if tariffs bring more jobs, U.S. manufacturers will likely have a hard time filling them. About 60% of respondents to the National Association of Manufacturers’ third-quarter outlook survey said attracting and retaining a quality workforce was a primary business challenge.

Harper has struggled to fill its ranks, with the unemployment rate in Wichita hovering around 3% for much of the past few years. At times, Harper has turned to temporary staffing agencies and having employees work overtime. “Just finding good employees has been very challenging,” said Rose, the controller.

Most employees make between $16 and $22 an hour, according to Rose. Other costs, including for medical insurance and electricity for the factory, keep climbing.

In some ways, Harper has been slow to adapt to technological changes. It only recently hired a sales manager focused on e-commerce and is just starting to experiment with using social media to market its products. The company didn’t switch its record-keeping from paper to digital until about six years ago.

But Harper is also trying to patent novel designs to stand out and drum up business. The company’s vice president, engineering manager and assistant plant manager, Jose Mendoza, designed a five-in-one hand truck that switches positions with a press of a button, which Harper is rolling out and hoping could be a new bestseller.

“We try to innovate. That’s one of the ways that we are competing,” said Mendoza, who immigrated to Wichita from Honduras when he was 16 and started working on Harper’s factory floor after high school more than two decades ago. “But it’s getting harder and harder.”

Ruffin said he talks to Trump often, but doesn’t weigh in on policy issues. In addition to being a business partner, Trump was Ruffin’s best man at his 2008 wedding to former Miss Ukraine Oleksandra Nikolayenko. Ruffin has been a steadfast supporter and donor to the president-elect and said he was with Trump on election night.

“He’s a very brilliant businessman,” Ruffin said of Trump. “I’m really, really excited to see what he’s going to do.”

Write to Hannah Miao at hannah.miao@wsj.com