Tougher than Hell & built to last


“Listen and deliver.”

It may sound simple, but this short phrase characterizes Diablo Furnaces’ approach to custom heat treat furnace engineering as one of the newest and leading manufacturers in the Midwest. Based in a northern suburb of Rockford, Illinois, the team of people working at Diablo boasts a long-time devotion to their craft and excitement for the future of furnace manufacturing. The story of how they began is as unique as their slogan, “Tougher than Hell and Built to Last.”

The only custom furnace manufacturing company in the region, Diablo has brought a refreshingly innovative perspective to traditional mechanical furnace design. Not only that, but Diablo is investing in the next generation of their workforce to ensure the legacy of their small but-mighty company grows beyond its current scope to continue serving their impressive portfolio of big-name customers.

As they begin to broaden their scope of customizations and new furnace design, production and servicing, Diablo anticipates a boom of growth into the $10 million company size range over the next decade.


Diablo Furnaces started as Machine Tool Builders’ (MTB) newest business venture when a long-time, local heat treating company decided to close its doors. Coming as an unexpected shutdown for many of their own workers, this company left its customers in the lurch to find a regional furnace service provider to which to give their business.

With significant industry overlap, Machine Tool Builders saw a widening gap in the market that was begging to be filled. As a well established machinery rebuilder, MTB began the internal new business discussions and decided to mobilize a team to begin an offshoot of their current business which ultimately formed an entirely new company, Diablo Furnaces.

With a shared leadership team and office space at the time of their initiation, Diablo inherited the reputation equity MTB had built since its founding in 1995. However, the team realized early, that this new venture had the potential to grow exponentially if differentiated enough as an entity in the market to capture an increasing demand for parts and new furnace design.

Positioned perfectly to absorb much of the local closing company’s workforce, Diablo started with a strong team of well-trained furnace and machine building technicians, engineers and sales people. With a veteran workforce, MTB’s reputation for excellence, and the transferred customer base from the closing company, Diablo had the perfect launch pad for success. They now sit at the top of the Midwestern furnace manufacturing hierarchy and are leading the way in innovative new designs, customizations and a service model that is hard to beat.


Starting as a company wing of MTB, Diablo Furnaces has a unique view of manufacturers that has shaped how they have decided to market their products and services. They observed that more and more manufacturers are upgrading certain pieces of their machinery in their factory line.

Automation and digitization has sparked a surge of new asset investment for many manufacturers; however, this is often an incremental process that results in a hybrid of old and new machinery. The integration of the two creates unique challenges and demands to ensure seamless transitions between systems and parts.

Seeing this digital transformation combined with the slower adoption rates of many manufacturers in their region, Diablo Furnace began to emphasize their ability to do customizations. As a part of this early initiative as a company, Diablo is expanding their available line of equipment offerings to meet the capacity needs common to many manufacturers. These include larger capacity tempering furnaces, carburizing furnaces, and other ancillary equipment capable of capacities up to 5000 pounds per load.

They also have a unique service model that includes onsite servicing to troubleshoot malfunctions on antiquated equipment – whether a fix
can be done to the old or a new unit is required, Diablo’s team prides themselves on always doing what the customer wants. Whether
that is recontrolling and retorquing an existing furnace in a line or doing a new installation, Diablo works onsite both with captive houses and commercial heat-treating companies all over the United

Working with an impressive portfolio of major manufacturers like Boeing, Body Coats, Diablo Furnaces has taken extreme measures to ensure their customers are serviced speedily. Storing hundreds of stock parts for both old and new furnaces that are found in manufacturing settings, they stand out from many OEMs that turn down customizations of any kind.

Perhaps most impressive of all for a new player in the furnace market, they are taking a consultative approach to problem solving, helping their customers look at the bigger picture of how a furnace’s placement, output and design affects both up and downstream production.


Seeing this need in manufacturing for custom furnace engineering, Diablo Furnaces invested in a team of engineers with a broad-sweeping knowledge of furnace and machine design expertise. Diablo has gone to market as one of the only Midwestern furnace manufacturers to do fully-custom design and installation.

On a recent project for a customer’s specified processes, Diablo’s team designed an electric annealing furnace, which allows loading by an automated load table. After the anneal cycle, the furnace automatically discharges at the opposite end into a rapid quench tank, and after the quench cycle is complete, the load is automatically moved to the unload table for an operator to retrieve. This system allows the customer to efficiently keep a portion of their process in their plant instead of the costly need to send work out to another plant.

As an added perk, Diablo’s custom design aligns with the customer’s newly implemented lean manufacturing system.

Another project in development for a customer with a unique space constraint is a modular continuous mesh belt electric annealing furnace. This furnace has a modular design that is easier to install in the facility with limited space. By design, it is a furnace that allows the number of sections to be customized for the amount of time required in the furnace, which is ideal for processing smaller parts feeding from another upstream process.


Setting Diablo Furnaces apart from the pack of furnace manufacturers nationwide is Sue Harrod and her team of industry experts.

Bringing more than 20 years of manufacturing leadership experience, Harrod is Diablo’s Chief Operating Officer, but her role expands far beyond her daily duties as COO. She often finds herself in sales meetings, introducing customers to the vision and leadership team behind Diablo.

Harrod has a tightknit group surrounding her, which she says is critical to being successful in her role. People like Anne Miner, Diablo’s marketing lead, Rick Claeyssen and Burk Glogowski, two highly accomplished machine builders and technical advisors, are at the forefront of Harrod’s mission.

Convinced that what Diablo has to offer is unmatched in the industry right now, Harrod has bold predictions for company growth and keeps a compulsive tab on industry trends and shifts.

Helping lead her team in a customer-minded direction, Harrod has helped Diablo coin an internal mission statement: “What we strive to do at Diablo Furnaces is listen to the customer’s needs and develop an economical solution to fit their process and budget.”

Another part of her growing legacy has been to invest in the future of the company through workplace initiatives that encourage retirees to reenter the workforce on a part-time basis to pass down veteran knowledge to younger workers. Shaping the vision for the company’s succession plan, Harrod is working with her team to implement training programs for new hires that include knowledge shares, lunch and learns and new vendor relations.

At a glance, Diablo Furnaces is taking a simple yet innovative approach to serving their customers: listen and deliver. While there’s a lot of work that is required to listen to a customer’s demands and deliver on a custom-engineered furnace solution, Diablo is making it look effortless.