568-172 BUNA 70 SQUARE CUT RINGS

Ordered as SH70172, this is an AS568-172 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring supplied with an inside diameter of 8.237 in (209.22 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 8.443 in (214.45 mm). The square-cut ring resists the spiral failure that affects round rings on long reciprocating strokes.

It resists greases and lubricants, many alcohols, and propane and butane. That behavior comes from the compound itself: Buna-N (Nitrile) delivers strong abrasion and tear resistance, an economical choice for high-volume maintenance programs. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Applications involving ozone and direct sunlight or polar solvents call for a different compound. The profile itself contributes a rectangular section that will not roll in the groove 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.

Typical settings include general industrial maintenance, agricultural equipment, and fluid power.

This item is sold individually under part number SH70172. Nominal inside diameter is listed as 8 1/4 inch. Review your operating media and conditions against this specification before installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.