Honing put gear manufacturer on a path to precision

For more than 60 years, Forest City Gear has been a precision gear manufacturer, leveraging advanced techniques and technology to earn the business of customers as exclusive as NASA. At the heart of the company’s technology-focused philosophy lies a long-time relationship with Sunnen Products Co., manufacturer of honing systems, tooling, and accessories. The relationship helped Forest City set itself apart as one of the world’s most precise gear makers, and now the company’s parts are found on everything from fishing reels to the Mars Rovers.

Stetler and Evelyn Young started Forest City Gear in 1955. Their son, Fred Young, ran the company for nearly 50 years and now Fred’s daughter Kika Young is company president.

“Staying on the forefront of machine tool technology goes to our core values because it makes us a better partner for our customers,” Young says. “Likewise, Sunnen checks all the boxes we’re looking for in a partner – communication, quick response, and quality equipment.”

Forest City Gear specializes in crafting custom gear solutions tailored to the unique needs of diverse industries.

“Everything we make is custom, directly from a customer’s design or CAD file,” Young adds. “Our company’s strategic directive has always been: ‘excellence without exception.’ Always give the customer a higher level of quality than specified, and do it without adding much cost or time to a job. Our automated vertical honing systems allow us to hit tight tolerances and produce precision finishes easily and efficiently without adding production time.”

About 30% of Forest City’s work is aerospace-related, demanding high process capability where honing provides critical advantages in control and consistency.

From parts to assemblies

The collaboration with Sunnen has allowed Forest City Gear to expand its product line to gear assemblies where precision also plays an important role.

“We evaluated our Sunnen hones and how we used them over the years, and as the gear tolerance requirements got tighter, we started to take over more of the value stream,” says Jared Lyford, Forest City Gear director of operations. “We used to be more of a cut-teeth production, then we migrated to whole-part-complete, from raw material to finished part. Even after I.D. grinding, we needed to have more finite control of the bore tolerances, and that’s where the Sunnen machines came in. They allowed us to meet the roundness and perpendicularity for both finished parts and in-process requirements for gear finishing.”

Honing makes the difference

Forest City Gear’s principal products are fine and medium pitch custom gears, such as internal, spline, sprocket, helical, spur, and worms/worm gears. The company works to quality levels as high as AGMA 15 (DiN 2-3). Maximum O.D. on most parts is 20", except for worms (5") and worm gears (16"). Typical materials include 12L14, 1215, 4140, 8620, 9310, and various stainless grades, as well as aluminum, bronze, brass, Inconel, Hastelloy, titanium, plastics, wood fiber, and powdered metal.

Honing plays a pivotal role in ensuring quality and performance. By employing two Sunnen SV Series honing systems, as well as an SH-4000 tube hone, Forest City improves accuracy and surface finish in its gears. This meticulous approach enhances the durability and reliability of the gears and optimizes their performance.

Forest City Gear has used honing since the inception of its business. The company also tried hard turning, but found it more difficult to control quality, especially for micro finishes.

“On bore-type gears, we have found that automated honing is a good way to give the customer tighter control of bore size, roundness, straightness, and finish,” says Joel Miller, I.D./O.D. department supervisor at Forest City Gear. Miller is responsible for honing, lapping, and grinding. “The customer notices the difference in a smoother, quieter, more efficient drive.”

“I.D. grinding is a fine process for gears with larger (>0.75") bores and low L/D ratios (0.5:1), but our range of work includes smaller diameters and relatively deep bores,” Miller explains. “When you start to reach an L/D of 2:1, honing has a real advantage in speed of material removal, and over 5:1 you might start to see deflection on a grinding spindle, exacerbating taper issues.”

Forest City Gear uses Sunnen’s diamond-plated CGT tooling with the Sunnen MB30 honing fluid. “We’ve had excellent results with the diamond-plated tooling as far as consistent, cool cutting, holding size, and giving us long wear,” Miller adds. “And the Sunnen machines are tanks. We depend on them to be accurate and repeatable. We can run on Friday afternoon hitting split limit, come back Monday morning, turn the machine on and we’re within 20 millionths.”

Software upgrade

Forest City Gear had been using honing systems for so long that when a second SV Series machine was purchased in 2022, the software on the new machine had been upgraded. Fortunately, the new software is compatible with the older model honing machine, so a simple software upgrade was all that was needed.

The new Sunnen software proved to be a game-changer for Forest City Gear – making machine setups, operator training, and overall operational efficiency even more efficient. The new software introduced intuitive user interfaces, automated processes, easy tool setups, and enhanced compatibility. This allows operators to set up machines more efficiently, reducing the time and effort required for each setup.

“The intuitive nature of the new software reduced the learning curve for our operators,” Miller says. “With the user-friendly interfaces and simplified workflows, operators can quickly grasp the functionalities of the software, requiring less time for training. This saved us training hours and enabled operators to become more proficient, contributing to overall productivity.”

Through new software, Forest City gained access to advanced features designed to optimize various aspects of their operations. These include process monitoring, data analysis, and predictive maintenance, allowing the shop to identify and address inefficiencies more effectively, leading to smoother operations and improved overall performance. “With this new software our operators can monitor which fixture is running and where we are in the part run,” Miller adds. “This gives us built-in consistency across all operators and allows one operator to run multiple machines.”

From its start, and through three generations of leadership, Forest City Gear has emphasized quality and precision in its parts and products.

Forest City Gear
https://forestcitygear.com

Sunnen Products Co.
https://www.sunnen.com

Coolant automation

PHOTOS COURTESY OF RESPECTIVE COMPANIES

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FullShop Gen 3’s simplified fluid architecture makes system expansion easy, enhances dosing precision, and is easy to install for plant personnel. To expand, users simply add more manifolds and piping to extend Gen 3 throughout their plant. FullShop systems use common piping and standard plumbing fittings for easy installation.

168 Manufacturing
https://168mfg.com

Semi-automated fiber laser solution

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Laser Photonics Corp.
https://www.laserphotonics.com