
bisco Expands ESNA Lock Nut Online Catalog
bisco industries is excited to announce that we have expanded our online catalog of ESNA lock nuts. bisco’s expanded ESNA catalog includes data such as material, finish, thread size, and other relevant dimensions to facilitate easy design-in and confident purchasing.
Product Spotlight: MS21043-3 Military Standard Lock Nuts
MS21043-3 Self-Locking Hex Nuts
bisco now stocks MS21043-3 lock nuts (locknuts) along with many other lock nuts in the MS21043 series. bisco’s MS21043-3 corrosion resistant steel hex lock nuts meet military standard (MS) NASM21043 and fall under National Stocking Number (NSN) 5310-00-844-3302. MS21043-3 lock nuts provide secure fastening that combats loosening from vibration and torque making them ideal for high-stress applications such as aircraft and military equipment.
MS21043-3 Features

Introducing StressNut Rivetless Nuplates from NAFCO USA
In the world of aerospace fasteners NAFCO USA has built a reputation for quality, affordable, and innovative products. NAFCO USA’s latest product, stressnut rivetless nutplates, are no exception.
Product Spotlight: Acme Industrial MS51831 Keylocking Inserts
MS51831 Heavy Duty Key Locked Threaded Inserts
MS51831 specification inserts are heavy duty keylocking inserts made from corrosion resistant steel (stainless steel). MS51831 inserts can be easily installed using standard drills and taps and require no tangs to be removed. Like other threaded inserts, MS51831 series inserts are used to repair damaged threads or to improve the thread strength of the parent material. Common applications for MS51831 key locked inserts include aircraft, motor vehicles, communication equipment, and electronic and industrial enclosures.
Acme Industrial – MS51831 Insert Manufacturer
Acme Industrial manufacturers the complete series of MS51831 inserts including both non-locking and self-locking versions. Although Acme manufacturers the MS51831 inserts under their own part numbers, the inserts are fully certified to the MS51831 spec (see the cross reference table below). In addition, Acme’s inserts are manufactured in the USA and are always DFAR compliant. Stock info, pricing, and product information are available from authorized Acme Industrial distributor, bisco industries. Visit biscoind.com or click on a part number in the table below to learn more.
Acme Industrial MS51831 Insert Cross Equivalents
MS51831 Insert Part Number |
Acme Industrial Part Number |
MS51831-101 | 217-076301 |
MS51831-101L | 217-077301 |
MS51831-102 | 217-076302 |
MS51831-102L | 217-077302 |
MS51831-103 | 217-076303 |
MS51831-103L | 217-077303 |
MS51831-104 | 217-076304 |
MS51831-104L | 217-077304 |
MS51831-105 | 217-076305 |
MS51831-105L | 217-077305 |
MS51831-106 | 217-076306 |
MS51831-106L | 217-077306 |
MS51831-107 | 217-076307 |
MS51831-107L | 217-077307 |
MS51831-108 | 217-076308 |
MS51831-108L | 217-077308 |
MS51831-109 | 217-076309 |
MS51831-109L | 217-077309 |
MS51831-110 | 217-076310 |
MS51831-110L | 217-077310 |
MS51831-111 | 217-076311 |
MS51831-111L | 217-077311 |
MS51831-201 | 217-076501 |
MS51831-201L | 217-077501 |
MS51831-202 | 217-076502 |
MS51831-202L | 217-077502 |
MS51831-203 | 217-076503 |
MS51831-203L | 217-077303 |
MS51831-204 | 217-076504 |
MS51831-204L | 217-077504 |
MS51831-205 | 217-076505 |
MS51831-205L | 217-077505 |
MS51831-206 | 217-076506 |
MS51831-206L | 217-077506 |
MS51831-207 | 217-076507 |
MS51831-207L | 217-077507 |
MS51831-208 | 217-076508 |
MS51831-208L | 217-077508 |
MS51831-209 | 217-076509 |
MS51831-209L | 217-077509 |
MS51831-210 | 217-076510 |
MS51831-210L | 217-077510 |
MS51831-211 | 217-076511 |
MS51831-211L | 217-077511 |

What is a Locknut?
A locknut is a nut specifically designed to stay fastened despite vibration or other environmental stresses. In order to stay locked in placed locknuts utilize surfaces that increase friction and reduce the possibility of the nut coming loose. The most common way to increase the surface friction is to add a nylon patch to the locknut’s threads. In some cases friction is also increased by fabricating locknuts with a slightly oval shape. Locknuts come in in various types including jam nuts, speed nuts, flex-top locknuts, distorted-thread locknuts, and castle nuts.
Locknut Applications
Needless to say, high quality and reliable locknuts are integral to many applications. Some of the most popular applications for locknuts are aircraft, military equipment, and machinery. These applications typically experience high stress and it is critical for safety and performance that components stay securely fastened.
Locknut Suppliers
Popular locknut brands include SPS Flexloc, MacLean ESNA, Micro Plastics, and Republic (Alcoa). Thanks to companies like Nylok standard nuts can also be converted into locknuts by adding a nylon patch. For more detailed locknut specifications and technical info view MacLean ESNA’s Catalog. Ready to buy? bisco stocks a wide range of locknuts for military, aerospace, and industrial applications. Search biscoind.com or contact us for price and availability.

How Ergonomic Components Enhance Aircraft Interiors
Aerospace Industry Focused on Lightweight Design
Many aircraft original equipment manufacturers are concentrating efforts on stripping weight out of everything from the aircraft bodies to passenger seating. With new developments in technology and design and increasing demand for improved performance at reduced costs, locating and utilizing the most efficient, lightweight parts is more important than ever. However, utilizing lightweight materials in certain applications can come with its own set of challenges. For example, design engineers working on aircraft interior applications must replace traditional materials with lightweight materials without sacrificing quality or end user comfort. One way, engineers are overcoming this obstacle is by using lightweight positioning solutions on interior cabin applications, like food trays, inflight entertainment systems, interior doors and panels.
Lightweight positioning solutions provide ergonomic functionality for passengers as well as crew members and maintenance personnel. Passenger comfort and usability can be greatly increased by using ergonomic torque hinges and display mounts that provide a full range of motion. Not only do lightweight positioning solutions enhance ergonomic functionality for passengers but they also promote fuel efficiency thereby reducing costs in the long run.
Southco: The Trusted Leader in Lightweight Positioning Solutions
Southco is the industry leader in “lightweighting” latch, handle, hinge and display mount designs and bisco industries is a premier authorized distributor for Southco. To learn more about how Southco ergonomic hinge and display mount solutions are helping to increase aircraft efficiency download Southco’s Aerospace Positioning Solutions Industry Report.
Know which part you need or still specing in an item? Southco’s microsite on biscoind.com allows you to search by product number or product type. bisco’s e-commerce website also provides online quoting and purchasing for your convenience. Visit biscoind.com today!