568-018 BUNA 70 SQUARE CUT RINGS

APG stocks the SH70018, an AS568-018 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring measuring an inside diameter of 0.739 in (18.77 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 0.879 in (22.33 mm). A square-cut ring resists the spiral failure that affects round rings on long reciprocating strokes.

The compound resists hydraulic fluids, greases and lubricants, and water. Buna-N (Nitrile) is known for an economical choice for high-volume maintenance programs and low compression set under sustained load. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). The profile itself contributes a flat contact band that spreads sealing load across a wider area and greater resistance to extrusion than a round section of the same size. Note that a square section is less suited to high-speed rotary service, where the larger contact area raises friction and heat.

It sees regular use in hydraulic and pneumatic systems, general industrial maintenance, and automotive.

Reference part number SH70018 when ordering; the item is sold individually. Unit weight is approximately 0.2227 g and nominal inside diameter is listed as 3/4 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. For a size or compound outside the standard catalog, APG can quote from a print or sample.