Plastic bearings are very popular for use on metal surfaces.  Plastics offer many advantages over other common bearing materials.  Plastics are extremely corrosive resistant and most are chemically resistant.   Plastic bearings do not transfer heat to other areas of the mechanical assembly.  Many plastics are even self-lubricating and therefore eliminate the possibility of failures from lack of maintenance.

Although many different types of plastics have properties which make them suitable for bearing applications, the most commonly used are phenolics, acetals, Teflon (PTFE), ultra high molecular weight polyethylene (UHMWPE), and nylon. The major limitations involved in the use of plastics have to do with high temperatures and possible cold flow under heavy loads.

1)  Phenolics: The compatibility of the phenolics makes them easily lubricated by various fluids. They have replaced metal bearings in such applications as propeller and rubber-shaft bearings in ships and electrical switch-gear, rolling-mill, and water-turbine bearings. In small instruments and clock motors, laminated phenolics serve as structural members as well as a bearing material. They have excellent strength and shock resistance coupled with resistance to water, acid, and alkali solutions. Phenolic plastic bearings work well in heavily loaded systems provided sufficient clearance and cooling is provided.

2)  Nylon: Although the phenolics have predominated in heavy-duty applications, they are frequently replaced by nylon, which has the widest use in plastic bearings. Nylon bushings exhibit low friction and require no lubrication. Nylon is quiet in operation, resists abrasion, wears at a low rate, and is easily molded, cast, or machined to close tolerances. Improvement in mechanical properties, rigidity, and wear resistance is obtained by adding fillers such as graphite and molybdenum disulfide to nylon. While the maximum recommended continuous service temperature for ordinary nylon is 170°F, and 250°F for heat-stabilized compositions, filled-nylon parts resist distortion at temperatures up to 300°F.  As mentioned in some of our other posts, nylon is also very inexpensive.

3)  Teflon (PTFE): Teflon is a great material for bearings for several reasons. It has an exceptionally low coefficient of friction and high self-lubricating characteristics, immunity to almost all types of chemical attack, and ability to operate over an extremely wide temperature range (-330 to 360°F continuous, to 550°F short-term).  PTFE’s load capacity depends on construction and reinforcing material. PTFE is a great choice for applications that include exposure to weather, chemicals, or vapors which can attack metals, lubricants, and some plastics.  Teflon bearings are also ideal for applications like sluice gates that involve the need to operate smoothly, reliably, and without sticking after prolonged idle periods.  Other applications for PTFE include those with low rpm, oscillatory or intermittent service, or where reliable service without lubrication is vital. The major drawback to using Teflon is that the cost of PTFE is high relative to plain metal or other resins.

4)  Acetal (Delrin): Delrin is a popular material for inexpensive bearings in a wide variety of automotive, appliance, and industrial applications. Delrin is particularly useful in wet environments because of its stability and resistance to wet abrasion.

5)  Ultrahigh-molecular-weight polyethylene (UHMWPE): UHMWPE bearings resist abrasion and have a smooth, low-friction surface.  UHMWPE is often an ideal replacement material for parts typically made from acetal, nylon, or PTFE materials.

5 not enough?  Here’s a few more!

Polyimide, polysulfone, polyphenylene sulfide:  These are high-temperature materials with excellent resistance to both chemical attack and burning. With suitable fillers, these moldable plastics are useful for PV factors to 20,000 to 30,000. Polyimide molding compounds employing graphite as a self-lubricating filler show promise in bearing, seal, and piston ring applications at temperatures to 500°F.

What materials do you prefer for bearings?  Let us know in the comment section below!  

Need more information on engineering plastics?  Check out our High Performance Plastics Material Guide!

11 responses to “Top 5 Materials for Plastic Bearings Used on Metal Surfaces

  1. Can you supply plastic bushes they are for a machine that uses sea water . There is a stainless steel shaft that goes through them. The shaft doesn’t spin it goes up and down about 60 times per minute..
    Sizes are
    OD 25 mm. X ID 20 mm X 65 mm long
    ID 15mm. X ID 12 mm X 55mm long


    Alex Wyllie.

  2. What you’re looking for is called plastic rod. We don’t supply it, but if you look on-line you’ll find suppliers. They will also be able to help you with the options they suggest for bearings.
    Good luck!

  3. Damn informative!! Thanks for sharing the information with us!! UHMWPE is highly abrasion resistant and just due to this reason I prefer to use bearings made with it. For all my custom bearings and UHMWPE extrusion needs, I trust The Spiratex Company. Thanks!!

  4. hi i have an old school merry go round at the top of the main support structure is a shaft aprox150m dia and about a 100m deep its a wite plastic bush looks like teflon running on a steel shaft do i need to grease itatahanks tony.

    1. Hi Tony – Thanks for reading the Craftech Industries’ posts. IF the component you refer to is indeed teflon, it shouldn’t need lubrication Teflon has low friction and is often used where sliding action of parts is needed – such as in bearings. Perhaps you could check with the maker of the equipment if known? Good luck!

  5. Hi could you supply or advise on a metal to metal wearing application.
    I’m looking to replace the wear plates in a rock breaker that are not made any more, the temperature shouldn’t cross 150c however there would be oil and grease contamination and the compressive shock loading would be quite high @ about 300hz.
    Any advice would be greatly appreciated.

    1. Leo – Thanks for reading the Craftech posts. Unfortunately, we can’t be of much help on metal questions – our expertise is with plastic.

  6. Trying to make fences to work on old flipper Elu saw. The fences slide on 18 mm steel round rod. One fence slides at right angles to saw blade and the other parallel to blade. Both operations require fences to slide along rods and then be fixed in position for cutting wood. The fence that works at right angles slide from before blade through till after blade ie crosscut. This fence slides on aluminium slider but is placed in position on steel rods as mentioned. Will Ptfe drilled to 18 mm dia allow fences to slide ok along rods?

    1. Steve – Thanks for your interest in the Craftech Industries’ posts. The answer is yes – in fact most types of plastic should fit your need.

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