Sumitomo Cutting Tools: For the Jobs Others Walk Away From

Riverside Spline and Gear Inc. is known for taking on the tough jobs and seeing them through. How tough? Competitors have been known to send them projects they don’t want to tackle. Based in Marine City, Michigan, Riverside has been a world-class supplier of custom gears and components for the country’s largest industries since 1963. Their main area of expertise is making specialty gears and shafts, particularly for mining applications.

A typical run is one or two gears, but the shop occasionally has larger runs up to 50 pieces. The average size gear they machine is 30” in diameter. They can also go as large as 70” or as small as 7/8 of an inch in diameter. Shaft projects can run up to 68” in length. To keep quality under control, they like to do everything in-house.

Defining “Tough”

Hardened steel is challenging to cut under the best of circumstances. Customers often drop off their own large forgings, which are typically harder than the norm. “They say it’s similar to 8620 steel, but sometimes it is not even close,” states Plant Manager Jeff Krause.

“We get some nasty-looking steel coming in through the doors. They look like a wheel off of Fred Flintstone’s car.”


No matter what the actual composition of the material, or what it looks like, Riverside needs to cut it. Finding the right cutting tool insert for the job is essential. That’s where Sumitomo comes in.

Steel that resembles a wheel from Fred Flinstone’s car.

Starting with Sumitomo

Originally, Riverside was using inserts made by other tooling companies. They worked, but it took four inserts using all eight cutting edges to get through one part. Lou Rahhal from Sumitomo distributor D&M Tooling suggested they try Sumitomo’s CBN (Cubic Boron Nitride) inserts. They gave them a try and finished a part with only a single edge on one insert. It wasn’t long before they were able to pick up speed, running even faster than Sumitomo recommends. The tools still held up. That was four years ago and Riverside has been a fan ever since.

Jeff Krause and Lou Rahal.

Staying with Sumitomo

After their success with Sumitomo’s CBN inserts, Riverside started using their carbide inserts for soft turning. They also use the Sumi-notch hard grooving system for cutting snap ring grooves in hardened parts after heat treating. Sumitomo’s carbide drills are the latest products currently in the testing phase.

Not knowing what will come into the shop next is just another part of the job at Riverside. Jeff explains their insert needs to Lou, who recommends the right chip breakers and grades for every job. “CBN isn’t cheap and we spent a lot of money on failure in the past,” said Jeff. “With Sumitomo, we have quality cutting tools that give us the consistency and long life we need to make a decent profit.”

If you have a reputation for handling the tough jobs, contact us for a consultation on some tough cutting tools.