568-028 BUNA 70 SQUARE CUT RINGS

Part number SH70028 is an AS568-028 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring measuring an inside diameter of 1.364 in (34.65 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 1.504 in (38.2 mm). A square-cut ring presents a flat rectangular section that cannot roll or twist in its groove, making it a dependable static seal.

The compound resists greases and lubricants, propane and butane, and petroleum-based oils. That behavior comes from the compound itself: Buna-N (Nitrile) offers low compression set under sustained load, reliable performance in both static and dynamic service. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Applications involving ketones or automotive brake fluid call for a different compound. The profile itself contributes greater resistance to extrusion than a round section of the same size and simple lathe-cut manufacture at low tooling cost. Note that a square section is less suited to high-speed rotary service, where the larger contact area raises friction and heat.

Common environments for this compound include general industrial maintenance, agricultural equipment, and construction equipment.

This item is sold individually under part number SH70028. Unit weight is approximately 0.355 g and nominal inside diameter is listed as 1 3/8 inch. Review your operating media and conditions against this specification before installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.