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Marine Fasteners RP-1421 5/16in Lock Washers 100-Pack

Manufacturer

Marine Fasteners

<h3>About Marine Fasteners</h3><p>For decades, <strong>Marine Fasteners</strong> has built its reputation on a straightforward promise: stock quality hardware, keep plenty of it on the shelf, and back every order with knowledgeable customer service. Recognized as America's leading supplier of marine, solar, and industrial fasteners, the company has followed this philosophy since 1975. That long track record of reliability has made Marine Fasteners a go-to source for boatbuilders, solar installers, contractors, and industrial maintenance crews alike.</p><h3>A Specialist in Corrosion-Resistant Hardware</h3><p>What sets Marine Fasteners apart is its deep focus on materials engineered to survive punishing environments. The brand carries a full line of 304 and 316 stainless steel bolts, socket products, screws, nuts, washers, pins, and specialty fasteners, and also offers multiple secondary processes along with a proprietary line of chrome-plated inventory. This breadth of material options means customers can match the exact alloy grade to their application — whether that's a saltwater-exposed through-bolt on a boat deck or a structural anchor in a solar panel array.</p><p>With more than 35 years of thriving in demanding conditions and a team boasting over 700 years of combined experience, Marine Fasteners understands the nuances of stainless steel fastener requirements across a wide range of industries. That institutional knowledge translates directly into better product selection guidance and fewer costly specification mistakes.</p><h3>A Comprehensive Catalog Under One Roof</h3><p>The Marine Fasteners catalog spans an impressive range of hardware categories. Core product lines include bolts, nuts, screws and threaded products, washers, U-bolts, anchors, socket products, cable ties, rivets, rods and studs, snaps, hose cable and cushion clamps, clips and retaining rings, drill bits, pins, driver bits, hex keys, and kits and assortments. This single-source approach simplifies procurement for professionals who need a wide variety of fastener types without juggling multiple suppliers.</p><p>The brand also distributes specialty sub-lines to meet niche demands. The <strong>Fasco Fastener</strong> division — a proprietary Marine Fasteners line — covers packaged cable ties, packaged chrome fasteners, packaged cushion clamps, and packaged hose clamps, making it easy for retailers and distributors to merchandise pre-packaged hardware. For self-drilling applications, Marine Fasteners stocks the <strong>Elco</strong> product line, which includes 18-8 and bi-metal steel self-drilling screws in a range of diameters and lengths with Stalgard finish for superior corrosion protection.</p><h3>Materials Built for the Elements</h3><p>Choosing the right fastener material is critical in marine and outdoor environments. Stainless steel grades such as AISI 304 and AISI 316 are common choices due to their strength and corrosion resistance, with 316 offering superior resistance to chlorides found in seawater and deck hardware exposed to spray. Marine Fasteners stocks both grades across its full product range, along with silicon bronze, brass, nylon, aluminum, and hot-dip galvanized options to suit every substrate and exposure level.</p><p>Whether you're sourcing a few hundred bolts for a dock repair or placing a large industrial order for a manufacturing facility, Marine Fasteners has the inventory depth, material expertise, and product variety to get the job done right.</p>

Part Number

RP-1421
05/31/2036 9:47 PM
Sale Price

$6.18

In Stock (10+)

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Usually delivered within 2 days

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No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Marine Fasteners RP-1421 is a 5/16-inch split lock washer crafted from 18-8 stainless steel, engineered to keep fasteners secure in demanding marine and outdoor environments. Each pack contains 100 washers, making it ideal for both professional installers and serious DIYers who need a reliable bulk supply.

Split lock washers — also known as spring lock washers — feature a helical cut that generates axial spring tension between the fastener head and the mating surface when tightened. This tension resists loosening caused by vibration, hull movement, and engine torque, providing a dependable hold in high-stress applications.

Key Features:

  • Size: 5/16 inch — fits standard 5/16" bolts and screws
  • Material: 18-8 stainless steel for strong corrosion resistance in marine, saltwater, and outdoor environments
  • Split-ring design: Creates spring tension that resists vibration-induced loosening
  • Quantity: 100 washers per pack — convenient bulk packaging for larger projects
  • Versatile use: Suitable for marine hardware, boat deck fittings, dock assemblies, automotive, and general mechanical applications
  • Compatible with standard 5/16" bolts, screws, and nuts

The Marine Fasteners RP-1421 lock washers are a cost-effective solution for any application where fastener security and corrosion resistance are critical. Simply place the washer between the fastener head (or nut) and the mounting surface, then tighten until the washer flattens and its edges engage both surfaces to resist rotation.

Really easy !

Very good service

nice and easy

The delivery was late it was FedEx fault but thmotorsports refund my ten dollars charges for two days shipping. Wonderful service i will order from them again and again.

Found the best price for the tires I needed here. Mixed production years but can't complain for the price. Arrived very quickly.

Good pricing easy to navigate

No

I have one of these on another boat. I love it and it&amp;#039;s saved my lower unit more than once when I unexpectedly found a stump or hard bottom.. It also allows me to run with the motor higher because if the set back.

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