Master Builders 

Hessert machinists create precision parts for research

When air speeds inside a hypersonic wind tunnel are expected to reach 4,000 miles per hour, the crafting of the most critical part of the tunnel — its 25-foot, 5-ton stainless steel nozzle – needs to be hyper-exact.

So the aerospace engineers designing Notre Dame’s Mach 6 wind tunnel turned to their in-house experts at the machine shop in the basement of the Hessert Laboratory for Aerospace Research.

“There need to be 21 pieces that can fasten together because each piece needs to be hand polished to perfection to minimize friction,” said Gene Heyse, manager of the machine shop in the aerospace and mechanical engineering department. “It needs a 7 percent taper on the inside, and it has to be perfect to 1/10 of a thousandth of an inch. So we built our own gauge to measure it accurately.”

A tenth of a thousandth of an inch is 40 times smaller than the width of a human hair.

That kind of problem-solving and that level of precision are why professors and researchers across campus and beyond turn to the Hessert machine shop to build the devices they need for cutting-edge research.

As a Notre Dame core facility, the shop charges $59 per hour, less than outside companies that may charge $85 to $200 an hour. The machinists there regularly make complex propellers and foils for wind tunnel research, but their projects can range from mosquito experiments to dune buggy gear boxes.

In another case, the University power plant wanted to resurface a 1955 boiler door that had warped. Since no blueprint could be found, Heyse and his fellow machinists used a massive computer-controlled Hurco mill to figure out the contours and create a new blueprint.

“They said the screws were going to cost $1,200 each to buy,” said Mike Sanders, another machinist. “We made them for $500 total and they bought us pizza.”

Heyse, Sanders and Terry Jacobsen were all born in South Bend and worked for years in local machine shops, including a dozen years together at the same place. They made parts for everything from power brake units in cars to aircraft fuel controls for Honeywell. It can take half a year to learn how to run the computerized mills and lathes that do the precision grinding and cutting — and longer to become expert at troubleshooting and special projects.

In other shops, Heyse said machinists get handed the specs and told to make a certain number of whichever widget is needed. The machinists get a paycheck but not much satisfaction.

“But here, there’s a lot of innovative ideas and testing,” he said. “The projects are often done to prove a theory rather than to make money for the boss. These brilliant professors know what they want to build, but they want our opinion on how to do it. It’s more of a partnership.”

Heyse, 60, who started at Hessert six years ago, so preferred the collaborative method of creation that he eventually lured his friend Jacobsen, 56, a year after he started and Sanders, 50, a year after that.

“I asked them, ‘How many shops have you worked at where people are happy, where it’s a community?’” Heyse said. “It makes you proud of what you’re making when you can help people try to get it right.”