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Military Standard MS28777-12 Leather Retainer, Packing - 3/Pack
Military Standard MS28777-12 Leather Retainer, Packing - 3/Pack
PART #: SGP137138-X3MFR PART #: MS28777-12Our Price: $56.79 (3/Pack)QTY: Add to Cart -
National Aerospace Standard NAS1523C08B Packing with Retainer - 5/Pack
National Aerospace Standard NAS1523C08B Packing with Retainer - 5/Pack
PART #: SGP140716-X5MFR PART #: NAS1523C08BOur Price: $38.90 (5/Pack)QTY: Add to Cart -
National Aerospace Standard NAS1523AA3E Packing with Retainer - 6/Pack
National Aerospace Standard NAS1523AA3E Packing with Retainer - 6/Pack
PART #: SGP140686-X6MFR PART #: NAS1523AA3EOur Price: $35.82 (6/Pack)QTY: Add to Cart -
National Aerospace Standard NAS1523-4E Packing with Retainer - 25/Pack
National Aerospace Standard NAS1523-4E Packing with Retainer - 25/Pack
PART #: SGP140648-X25MFR PART #: NAS1523-4EOur Price: $108.50 (25/Pack)QTY: Add to Cart -
Military Standard MS28782-21 Teflon (PTFE) Retainer, Packing - 50/Pack
Military Standard MS28782-21 Teflon (PTFE) Retainer, Packing - 50/Pack
PART #: SGP137181-X50MFR PART #: MS28782-21Our Price: $100.00 (50/Pack)QTY: Add to Cart -
Military Standard MS27595-211 Retainer, Packing - 50/Pack
Military Standard MS27595-211 Retainer, Packing - 50/Pack
PART #: SGP136530-X50MFR PART #: MS27595-211Our Price: $69.50 (50/Pack)QTY: Add to Cart -
Military Standard MS9058-04 Teflon (PTFE) Retainer, Packing - 15/Pack
Military Standard MS9058-04 Teflon (PTFE) Retainer, Packing - 15/Pack
PART #: SGP138581-X15MFR PART #: MS9058-04Our Price: $55.80 (15/Pack)QTY: Add to Cart -
Military Standard MS28782-3 Teflon (PTFE) Retainer, Packing - 3/Pack
Military Standard MS28782-3 Teflon (PTFE) Retainer, Packing - 3/Pack
PART #: SGP137190-X3MFR PART #: MS28782-3Our Price: $4.44 (3/Pack)QTY: Add to Cart -
Military Standard MS27595-125 Retainer, Packing - 25/Pack
Military Standard MS27595-125 Retainer, Packing - 25/Pack
PART #: SGP136508-X25MFR PART #: MS27595-125Our Price: $44.00 (25/Pack)QTY: Add to Cart -
Military Specification M8791/1-428 Teflon (PTFE) Retainer, Packing - 5/Pack
Military Specification M8791/1-428 Teflon (PTFE) Retainer, Packing - 5/Pack
PART #: SGP130349-X5MFR PART #: M8791-1-428Our Price: $71.90 (5/Pack)QTY: Add to Cart -
Military Standard MS27595-028 Retainer, Packing - 25/Pack
Military Standard MS27595-028 Retainer, Packing - 25/Pack
PART #: SGP136495-X25MFR PART #: MS27595-028Our Price: $27.50 (25/Pack)QTY: Add to Cart -
Military Standard MS27595-223 Retainer, Packing - 10/Pack
Military Standard MS27595-223 Retainer, Packing - 10/Pack
PART #: SGP136542-X10MFR PART #: MS27595-223Our Price: $23.80 (10/Pack)QTY: Add to Cart
Ask any Skygeek and they will tell you a back-up ring functions on the principle of "everything needs support." As its name implies, it is a sturdy ring that "backs-up" (usually a rubber) seal. It is designed specifically to hold or maintain this seal in its proper position.
In many assemblies, joints require a seal. This is done so as to prevent the leakage of fluid or gas. O-rings are often used as a seal. However, due to extreme pressures inherent in aviation, these seals may extrude or lose their place and thus compromise their intended use. Back-up rings prevent extrusion and thus are used in conjunction with O-rings.
Back-up rings, like their O-ring counterparts, are usually made of elastic polymers, the most common being nitrile butadiene rubber (NBR) and polytetrafluoroethylene (PTFE or Teflon). Like other materials, elastomers are often given a hardness rating (durometer). This identifies a material's resistive strength, especially when dealing with pressures and other external forces. For instance, when viewing a back-up ring, you might find a 70 or 75A in its name; these numbers refer to its durometer.
Besides material, back-up rings can be classified by type, three variations include: spiral, endless, and endless split. A spiral back-up ring is the most frequently used because of its ability to efficiently self-adjust to diametrical tolerances. Endless back-up rings are applied whenever problems occur with the rotation of screwed endcaps that may cause a spiral type to unwind. The endless split back-up ring is identical to the endless back-up ring, the only difference is it is split at a 30-degree angle; this facilitates assembly for some applications.
Finally, back-up rings conform to several military specifications and Skygeek carries them including: MS27595, M8791, and MS9058. Our inventory is growing so check in from time to time. Otherwise, click on the specific series of back-up rings and make sure your seals are supported.