568-388 BUNA 70 SQUARE CUT RINGS

Ordered as SH70388, this is an AS568-388 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring supplied with an inside diameter of 18.953 in (481.41 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 19.373 in (492.07 mm). The square-cut ring resists the spiral failure that affects round rings on long reciprocating strokes.

Buna-N (Nitrile) is specified here for reliable performance in both static and dynamic service, strong abrasion and tear resistance. The material holds up against hydraulic fluids, petroleum-based oils, and greases and lubricants. 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 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 fluid power, agricultural equipment, and construction equipment.

Reference part number SH70388 when ordering; the item is sold individually. Nominal inside diameter is listed as 19 inch. Check the compound against your process media, pressure and temperature before committing to a design. For a size or compound outside the standard catalog, APG can quote from a print or sample.