Your browser is out of date.

You are currently using Internet Explorer 7/8/9, which is not supported by our site. For the best experience, please use one of the latest browsers.

What is a Polygon Profile?

What is a Polygon Profile?

Kinematically ground polygonal shapes have been used as drive connections for more than 45 years. What is now referred to as Polygon Systems was developed by Fortunawerke, Stuttgart, West Germany, who patented a grinding machine capable of producing matched polygonal shaft and bore diameters.

Learn More
Their Uses

Unique Features

The unique feature of the machine which made this possible was its wheelhead. Using a mechanical drive system, the wheelhead could be set to move the grinding wheel in an elliptical path to keep the wheel to the norm of the centerline of the workpiece as the work was rotated. By setting a ratio between the cycles of wheelhead movement and part rotation, polygons could be generated with any number of "sides" beginning with two, an oval shape.
The most commonly used shapes today have either three or four lobes, or sides. The three-lobed polygon can also be ground with a taper on the shaft and in the bore for an interlocking engagement. Three and four lobe forms can be press or sliding fits. Originally intended as a substitute for drive connection, using splines, keys, flats and serrations, polygons have now found their place in many other applications.

Our company is a contract shop providing the specialized grinding service. In the past years, few manufacturers had sufficient production to justify purchasing a Fortuna Polygon Grinder, although a number are being used proprietarily.
Polygon systems are also widely employed for repair of damaged drive connections. When costly shafts and hubs incorporating spline drive connections have failed through damage to the teeth, it is no longer necessary to totally replace them. This will also be discussed and illustrated later. Why, Where, And When To Use Polygons are not the answer to all problems. They provide optimum results but are not usually considered when less than optimum performance is satisfactory. Often, less costly methods will do. Generally, these are the reasons designers turn to polygons:

  • To overcome the problems usually found with spline connections, such as failure caused by various torsional effects.
  • To eliminate stress risers which cause part failure.
  • To provide maximum concentricity and low clearance, when required on connections such as "floating shafts".
  • To reduce backlash, which is near-zero with Polygon.
  • To provide optimum control of angular positioning, especially on long shafts. Grinding after hardening provides for this. Typically, parts can be oriented within 2 seconds of arc over a 24" shaft length, essential in many cam and gear assemblies.
  • To permit finish machining of high-torque parts after hardening. In all other methods, post-machining heating treating introduces various distortions in splined shafts.
  • To reduce manufacturing costs on large volume production items, especially in the areas of inspection and straightening.

Have questions? We’re here to help

contact us today
Industries Served

Industries Stoffel Polygon Services


Customer Stories

"We would like to thank the team at Stoffel Polygon Systems for completing our polygon adapter in an expedited manner. We are most appreciative of your focus and fine attention to detail. This has supported Goodrich in meeting the needs of our customers. The adapter has passed all inspections. This is a result of the fine level of workmanship we have received from Stoffel Polygon Systems. Thank you again for your teamwork on this project."

Michael O'Hara from Strategic Sourcing

"Kellogg Crankshaft recently received a very complimentary letter from Rotary Power International, Inc.'s Mr. W. B. (Bill) Silvestri regarding the specialized crankshafts for the Marine Corps. All of us in the industry recognize that praise is in limited supply today; our customers continually require more for less and faster. Kellogg would like to take this opportunity to recognize you, as our supplier, for providing quality, cost-effective services on this project. Rotary Power anticipates future opportunities, similar in nature, and will again be looking for a quality job and counting on all of us to offer suggestions to reduce costs wherever we can. Again, all of us at Kellogg Crankshaft thank you for your contribution to the success of Rotary Power International, Inc.'s five rotor crankshaft project. We look forward to continuing a mutually beneficial relationship with you on future work. "

Charles C Baker from Kellogg Crankshaft

"So nice to find a company so passionate about quality. Your shaft was (is?) beautiful. Perfect really. We, Conhagen, did not realize Stoffel would create shafts from scratch... In the future we will send you heat treated stock for your magic. We usually buy forged bars, annealed, quenched then tempered by our own heat treater. Normally, we run all 400 series stainless through a second temper after rough out as a stress relief operation to keep the shafts straight. "

Dennis Bowman from Conhagen
Learn More

Get in touch with Our Team

Fill out the quick form with any questions and one of our team members will reach out to you shortly.

199 Marbledale Road
Tuckahoe, NY 10707
Monday-Friday: 6:30am-5:00pm
Saturday: 6:00am-2:00pm