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Military Standard MS28777-20 Leather Retainer, Packing
Military Standard MS28777-20 Leather Retainer, Packing
PART #: SGP137141MFR PART #: MS28777-20Our Price: $18.48 (Each)QTY: Add to Cart -
Military Standard MS28777-12 Leather Retainer, Packing
Military Standard MS28777-12 Leather Retainer, Packing
PART #: SGP137138MFR PART #: MS28777-12Our Price: $10.45 (Each)QTY: Add to Cart -
Military Standard MS28777-3 Leather Retainer, Packing
Military Standard MS28777-3 Leather Retainer, Packing
PART #: SGP137143MFR PART #: MS28777-3Our Price: $5.82 (Each)QTY: Add to Cart -
Military Standard MS28777-24 Leather Retainer, Packing
Military Standard MS28777-24 Leather Retainer, Packing
PART #: SGP137142MFR PART #: MS28777-24QTY: Add to Quote -
Military Standard MS28777-2 Leather Retainer, Packing
Military Standard MS28777-2 Leather Retainer, Packing
PART #: SGP137140MFR PART #: MS28777-2Our Price: $3.98 (Each)QTY: Add to Cart -
Military Standard MS28774-122 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-122 Teflon (PTFE) Retainer, Packing
PART #: SGP136699MFR PART #: MS28774-122Our Price: $1.00 (Pack)QTY: Add to Cart -
Military Standard MS28774-137 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-137 Teflon (PTFE) Retainer, Packing
PART #: SGP136715MFR PART #: MS28774-137Our Price: $1.44 (Pack)QTY: Add to Cart -
Military Standard MS28774-128 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-128 Teflon (PTFE) Retainer, Packing
PART #: SGP136705MFR PART #: MS28774-128Our Price: $1.07 (Each)QTY: Add to Cart -
Military Standard MS28782-13 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-13 Teflon (PTFE) Retainer, Packing
PART #: SGP137172MFR PART #: MS28782-13Our Price: $1.52 (Each)QTY: Add to Cart -
Military Standard MS28782-26 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-26 Teflon (PTFE) Retainer, Packing
PART #: SGP137186MFR PART #: MS28782-26Our Price: $2.73 (Each)QTY: Add to Cart -
Military Standard MS28782-27 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-27 Teflon (PTFE) Retainer, Packing
PART #: SGP137187MFR PART #: MS28782-27Our Price: $2.69 (Each)QTY: Add to Cart -
Military Standard MS28782-3 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-3 Teflon (PTFE) Retainer, Packing
PART #: SGP137190MFR PART #: MS28782-3Our Price: $1.36 (Each)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.