Q&A: How do I select the right plane bearing?
We see this question often. Plane bearings offer many advantages; a simple design, self-lubrication, a wide range of operating parameters, and lower cost.
When selecting a plane bearing, consider:
Load – this can be the most difficult attribute to define. What is the pressure? Multiply the ID times the length, and then divide the load by that number. Pressure (P) is expressed in PSI.
Speed – you may know what your shaft speed is, but you need to find the velocity (v). Take the diameter multiplied by pi, then multiply by the RPM. Divide this number by 12, because V is measured in surface feet per minute (SFPM). Every material is rated for a maximum velocity.
P and V – these must always be considered in tandem. The combination of load and speed generates frictional heat. Always review P x V or PV. Every material has a maximum PV rating.
Material Rating – look at all the values for each individual project. Plastics are insulated in nature, and heat will kill a plastic bearing faster than anything else. Be sure to stay within the known limits to understand what materials are capable of taking.
Temperature – this is critical to getting the proper “press fit”. Be certain there is no loss of tolerance or close-ins.
You can also visit our Plane Bearing Design Worksheet for guidance, or contact us directly.
Tags: bearing grade plastics, plane bearings, self lubricating bearings
