568-338 BUNA 70 SQUARE CUT RINGS

APG stocks the SH70338, an AS568-338 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring built to an inside diameter of 3.1 in (78.74 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 3.52 in (89.41 mm). A square-cut ring presents a flat rectangular section that cannot roll or twist in its groove, making it a dependable static seal.

As a material, Buna-N (Nitrile) is known for reliable performance in both static and dynamic service, strong abrasion and tear resistance. It resists water, greases and lubricants, and petroleum-based oils. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Exposure to ketones or strong acids will shorten service life. The profile itself contributes simple lathe-cut manufacture at low tooling cost and a flat contact band that spreads sealing load across a wider area. Note that a square section is less suited to high-speed rotary service, where the larger contact area raises friction and heat.

Typical settings include construction equipment, fluid power, and hydraulic and pneumatic systems.

This item is sold individually under part number SH70338. Unit weight is approximately 8.7023 g and nominal inside diameter is listed as 3 1/8 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.