The best 5/16-18 flange nut depends on the quantity, material, and surface protection your project requires. Choose the GPJYYDS 304 stainless steel nuts for an outdoor-oriented stainless option, Juvielich or BCP Fasteners for a 50-piece zinc-plated set, Hicarer for bulk needs, or Hard-to-Find Fastener for a small Grade 5 steel assortment. Confirm the thread and dimensions against your bolt and application before ordering.
| Product | Best For | Pack Size | Material or Finish |
|---|---|---|---|
| GPJYYDS Serrated Flange Nuts | Stainless steel selection | 50 | 304 stainless steel |
| Juvielich Serrated Flange Nuts | Small equipment repairs | 50 | Zinc-coated carbon steel |
| Hicarer Serrated Flange Lock Nuts | Bulk projects | 1,000 | Galvanized steel |
| Hard-to-Find Fastener Grade 5 Nuts | Small Grade 5 quantity | 15 | Steel |
| BCP Fasteners Serrated Flange Nuts | General-purpose 50-piece supply | 50 | Zinc-plated |
GPJYYDS 304 Stainless Serrated Flange Nuts
Best for buyers who want a 50-piece supply made from 304 stainless steel. The manufacturer describes the nuts as suitable for outdoor use, making this set worth considering when stainless construction is preferred over a plated carbon-steel option.
These nuts have 5/16-18 threads and serrated flanges. Listed dimensions include a 7 mm height, 13 mm hex width, and 17 mm flange outside diameter. The listing states a dimensional tolerance of less than 0.2 mm.
Why it was selected: It combines the requested thread size, serrated flange design, a practical pack size, and a clearly identified stainless material. Limitation: Check the metric-listed dimensions against the space available in your assembly; the listing does not provide an application-specific load rating.
Juvielich Serrated Flange Nuts, 50 Pack
Best for buyers repairing equipment who need a modest quantity of 5/16-18 serrated flange nuts. The product name references chainsaws, mowers, and snowblowers, while the stated specifications identify the thread as 5/16-18 with 18 threads per inch.
The nuts are made from zinc-coated carbon steel. The listing gives a 1/2-inch hex drive, 0.271-inch overall height, and 0.6765-inch flange diameter. Fifty pieces arrive in a clear plastic box intended to keep them organized during storage and transport.
Why it was selected: Its stated measurements and packaged quantity make it a useful comparison for maintenance and repair buyers. Limitation: It is carbon steel with a zinc coating, not stainless steel; choose another material if your project specifically requires stainless fasteners.
Hicarer 1,000-Pack Serrated Flange Lock Nuts
Best for shops, production work, and frequent projects that can use a large quantity. This package includes 1,000 zinc-plated serrated flange lock nuts with 5/16-18 threads. The listing specifies a 0.563-inch nut diameter and a 0.669-inch flange diameter.
Hicarer identifies the construction as galvanized steel and describes the bright finish as corrosion-resistant. The serrated flange is the design feature to consider when comparing these nuts with plain, non-serrated flange nuts.
Why it was selected: The unusually large pack size suits buyers who want a substantial supply of the requested thread size. Limitation: A 1,000-piece package may be excessive for a one-time repair, and the listing’s stated dimensions should be checked against your hardware before purchase.
Hard-to-Find Fastener Grade 5 Flange Lock Nuts
Best for buyers seeking a small 15-piece quantity identified as Grade 5. The listing specifies a 5/16-inch diameter, steel material, and a thickness of 9/32 inch, making those dimensions useful checks before selecting this option.
Why it was selected: It provides a smaller pack and an explicitly stated Grade 5 designation, which can help when a project calls for that grade. Limitation: The supplied product details do not identify a coating or state the flange diameter, so verify those requirements if corrosion protection or a precise flange measurement matters.
BCP Fasteners Zinc-Plated Serrated Flange Nuts
Best for buyers who want 50 zinc-plated serrated flange nuts for general assembly or repair. The listed features confirm the 5/16-18 size, zinc plating for corrosion resistance, a 50-piece package, and a 1/2-inch hex drive.
Why it was selected: It offers a straightforward comparison with other 50-piece plated options and clearly states its drive size and finish. Limitation: The provided product details do not specify the steel grade or flange dimensions; check those details if your application requires them.
Buying Guide: Choosing 5/16-18 Flange Nuts
What does 5/16-18 mean?
It identifies a nominal 5/16-inch thread diameter and 18 threads per inch. Match both parts of the specification to the bolt or stud. A different thread pitch may not fit correctly, even when the diameter appears similar.
Should you choose stainless steel or zinc-plated steel?
The GPJYYDS option is listed as 304 stainless steel. The Juvielich, Hicarer, and BCP options are described as coated steel. Compare the material and finish with the exposure conditions and project requirements. Do not treat a coating as interchangeable with stainless steel.
Why choose a serrated flange?
A flange spreads contact across a wider area than a standard hex nut, while serrations are a feature of the nut’s bearing surface. Confirm that the serrations are appropriate for the mating surface, since surface marking may matter in finished or delicate materials.
How many nuts should you buy?
Choose a 15- or 50-piece package for limited repairs or modest projects. The 1,000-piece Hicarer package is better suited to frequent use or bulk requirements. Consider storage and expected use before selecting a large quantity.
Which dimensions should you verify?
Check the thread, hex width or drive size, nut height, and flange diameter against the installation space and tools available. Product listings do not provide all dimensions for every option, so seek clarification when a missing measurement is critical.
Frequently Asked Questions
Are all five products 5/16-18?
The product names or listed specifications identify all five as 5/16-18 flange nuts. Confirm the package labeling and thread specification before installation.
Are these flange nuts stainless steel?
No. The GPJYYDS listing specifies 304 stainless steel. The other listed options are steel with zinc or galvanized finishes, or steel whose coating is not specified.
Can a 5/16-18 nut fit any 5/16-inch bolt?
No. The bolt must also have 18 threads per inch. Match the thread pitch as well as the nominal diameter.
Which option has the largest pack?
Hicarer offers the largest listed quantity at 1,000 nuts. The other products list packages of 15 or 50.
Do the product details provide load ratings?
The supplied product information does not state load ratings. Do not assume a load capacity from the thread size alone; use specifications appropriate to the application.