Solid PTFE O-rings are used virtually in every industry as either a primary O-ring or a backup ring. They are excellent seals in applications that are subject to harsh chemical exposure, extreme temperature or pressure, as well as dynamic applications. PTFE O-rings demonstrate excellent abrasion resistance and performance in weathering elements such as ozone, UV, and water.  The major limiting factor of PTFE is the inability to compress easily, which is similar to its low coefficient of friction, and may not be ideal for some O-ring sealing applications.  While limiting for some applications, these factors may also perfectly qualify PTFE for use in other applications, such as dynamic sealing applications.  PTFE also exhibits good insulation qualities and has seen use in cables and electronic assemblies.

An example of the PTFE O-ring can be referenced in one of four ways:

l Mostly commonly, the industry standard AS568 +“dash”+ number, ex. AS568-028

l Standard dimensions: (CS 0.070" x ID 1.364")

l Metric dimensions: (CS 1.78 x ID 34.65)

l Nominal fractional dimensions: (CS 1/16 " x ID 1 3/8") 

The global O-ring and seal size reference chart covers the AS568 O-ring sizes published by the Society of Automotive Engineers (S.A.E.), and includes the extended sizes in the 400 series. The purpose of this chart is to specify the inside diameters, cross-sections, tolerances, and size identification codes (dash numbers) for O-rings used in sealing applications and for straight thread tube fitting boss gaskets.

Primary Uses of O-rings, Plastic Seals and Backup Rings:

l Dynamic applications and applications requiring lubricants

l Harsh chemical exposers

l Electronic, radio, microwave, cable insulation

l Backup ring applications

l General industrial uses.

AS568 SIZE CHART