Polygon Design Tips

Tip #1
Tip #2
Tip #3
Tip #4
Tip #1

Most often, either three-lobe (P3), or four-lobe(PC4) profile can be used. A few rules determine when to use either of them. P3 is used for most of the fixed connections, and when zero backlash is required, especially for frequently separated connections. A tapered P3 prevents a connection from self-locking, by using a 10 degrees included angle, or steeper tapers. The torque on the tapered profile, also generates an axial separating force. (A fastener or lock nut is required)

Tip #2

Most of the sliding connections use the PC4 profile. However, a P3 connection is acceptable with a low torque and high actuating force, as in hydraulic cylinders, and when sliding occurs under no-load.

Tip #3

PC4 sliding connections require greater force for axial movement under torque load than straight-sided splines. At zero torque load, they perform equally well, and often better than involute splines.

Tip #4

Polygon benefits such as increased strength, smaller space requirements, lighter weight, self-centering characteristics, simplified manufacturing techniques, concentricity, and angular orientation accuracy are maximized, when systems are fully designed around polygons from the outset.


  • Aerospace Industry

  • Bomb Disposal Robot

  • Compressors

  • Crushers

  • Drill Head Units

  • Dynamometers

  • Envelop Manufacturing Machines

  • Film Manufacturing Machines

  • Food Machinery

  • Gas Turbine Couplings

  • Gear Boxes

  • Stamping Machines

  • Glass Mold Machines

  • Harmonic Drives

  • Hydraulic Cylinders

  • Index Machines

  • Injection Molding Machines

  • Machine Tools

  • Marine Diesel Engines

  • Measuring Machines

  • Mechanical Seals

  • Mill Roll Heads

  • Milling Machines

  • Mining Equipment

  • Multi-Spindle Lathe Gear Systems

  • Oil Drilling

  • Packaging Machinery

  • Plastic Extruding Machines

  • Printing Presses

  • Pumps

  • Rotary Engines

  • Satellite Launchers

  • Steel Rolling Machines

  • Textile Machinery

  • Thread Rolling Machines

  • Tool Holders

  • Transmissions

  • Tube Bending Machines

  • Valve Actuators

  • Variable Speed Drives

  • Water Brakes

  • Winding Machines

  • Wire Drawing Machines

Click here to see the P3-PC4 Design Data!

Check out the Stoffel Research!