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National Aerospace Standard NAS1523AA3R Packing with Retainer
National Aerospace Standard NAS1523AA3R Packing with Retainer
PART #: SGP140689MFR PART #: NAS1523AA3ROur Price: $3.25 (Each)QTY: Add to Cart -
National Aerospace Standard NAS1523AA4B Packing with Retainer
National Aerospace Standard NAS1523AA4B Packing with Retainer
PART #: SGP140691MFR PART #: NAS1523AA4BOur Price: $23.80 (Each)QTY: Add to Cart -
National Aerospace Standard NAS1523C08Y Packing with Retainer
National Aerospace Standard NAS1523C08Y Packing with Retainer
PART #: SGP140721MFR PART #: NAS1523C08YOur Price: $3.25 (Each)QTY: Add to Cart -
National Aerospace Standard NAS1523AA08Y Packing with Retainer
National Aerospace Standard NAS1523AA08Y Packing with Retainer
PART #: SGP140669MFR PART #: NAS1523AA08YOur Price: $24.98 (Each)QTY: Add to Cart -
Military Specification M8791/1-129 Teflon (PTFE) Retainer, Packing
Military Specification M8791/1-129 Teflon (PTFE) Retainer, Packing
PART #: SGP130306MFR PART #: M8791-1-129Our Price: $1.10 (Each)QTY: Add to Cart -
Military Specification M8791/1-130 Teflon (PTFE) Retainer, Packing
Military Specification M8791/1-130 Teflon (PTFE) Retainer, Packing
PART #: SGP130307MFR PART #: M8791-1-130Our Price: $1.11 (Each)QTY: Add to Cart -
Military Specification M8791/1-216 Teflon (PTFE) Retainer, Packing
Military Specification M8791/1-216 Teflon (PTFE) Retainer, Packing
PART #: SGP130320MFR PART #: M8791-1-216Our Price: $0.70 (Each)QTY: Add to Cart -
Military Specification M8791/1-221 Teflon (PTFE) Retainer, Packing
Military Specification M8791/1-221 Teflon (PTFE) Retainer, Packing
PART #: SGP130325MFR PART #: M8791-1-221Our Price: $2.15 (Each)QTY: Add to Cart -
Military Specification M8791/1-228 Teflon (PTFE) Retainer, Packing
Military Specification M8791/1-228 Teflon (PTFE) Retainer, Packing
PART #: SGP130330MFR PART #: M8791-1-228Our Price: $2.44 (Each)QTY: Add to Cart -
Military Specification M8791/1-331 Teflon (PTFE) Retainer, Packing
Military Specification M8791/1-331 Teflon (PTFE) Retainer, Packing
PART #: SGP130337MFR PART #: M8791-1-331Our Price: $1.69 (Each)QTY: Add to Cart -
Military Standard MS27595-020 Retainer, Packing
Military Standard MS27595-020 Retainer, Packing
PART #: SGP136490MFR PART #: MS27595-020Our Price: $1.02 (Each)QTY: Add to Cart -
Military Standard MS27595-028 Retainer, Packing
Military Standard MS27595-028 Retainer, Packing
PART #: SGP136495MFR PART #: MS27595-028Our Price: $1.37 (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.