Best 3/8 Split Nuts and Locking Fasteners for Common Projects
For 3/8-inch fastening, the best choice depends on whether you need a split lock washer, a locking nut, or a standard hex nut. The Swpeet 75-piece kit is best for buyers who want nuts and washers together; Neprift is best for a pack of 3/8-inch split lock washers; and Vifmy is best for 3/8-16 nylon-insert lock nuts. The term “split nuts” can refer to different hardware, so confirm the part type and thread before ordering.
| Product | Best For | What It Includes |
|---|---|---|
| Swpeet 75-piece kit | Hardware assortment | Lock nuts, flat washers, split lock washers |
| Neprift split washers | Split lock washers | 30 stainless steel washers |
| Vifmy nylon lock nuts | Vibration-resistant nut fastening | 35 stainless steel 3/8-16 lock nuts |
| Swpeet 45-piece kit | Smaller mixed assortment | Hex nuts, flat washers, split lock washers |
| Makers Bolt hex nuts | Standard nut replacement | 100 coarse-thread hex nuts |
Swpeet 75-Piece 3/8-16 Assortment Kit
This kit includes 25 stainless steel hex lock nuts, 25 flat washers, and 25 split lock washers. Its mix of components makes it the most versatile pick for projects that call for both a nut and a washer. The listed lock nuts are described as 304 stainless steel and intended to hold fasteners securely.
Best for: Home, automotive, or shop users who want a larger assortment of related 3/8-inch hardware. Choose this if you need multiple component types in one kit. The listing does not specify an organizer box for this product, so plan storage separately if needed.
Neprift 3/8-Inch Split Lock Washers
This is the clearest match if “split” refers to a split lock washer rather than a split nut. The pack contains 30 washers made from 304 stainless steel. The product specifies a 0.37-inch inner diameter and 0.14-inch thickness, and describes offset split ends intended to resist loosening when installed under a nut or bolt head.
Best for: Buyers replacing or adding 3/8-inch split lock washers. It is a washer-only pack, not a nut assortment; avoid it if you need threaded nuts or a complete fastener set.
Vifmy 3/8-16 Nylon Lock Nuts
Vifmy supplies 35 imperial 3/8-16 nylon-insert lock nuts made from 304 stainless steel. The nylon insert creates friction against the bolt threads to help resist loosening, including in applications exposed to shock or vibration, according to the product details. Stainless steel construction is listed for rust and corrosion resistance.
Best for: Buyers who specifically need a locking nut instead of a split washer. Confirm that your bolt has 3/8-16 threads. These nuts do not include washers, and the nylon insert makes them different from ordinary hex nuts.
Swpeet 45-Piece Nut And Washer Kit
The smaller Swpeet assortment contains 15 hex nuts, 15 flat washers, and 15 split lock washers. The listed components are SAE 304 stainless steel, and the kit comes in a plastic organizer box for storage and carrying. It provides the key washer types alongside standard nuts without the larger quantities in the 75-piece kit.
Best for: DIY users who want an organized, smaller mix for occasional repairs. Choose this over the 75-piece set when 15 of each component is sufficient. The listed hex nuts are not identified as nylon-insert lock nuts.
Makers Bolt 3/8-16 Hex Nuts
This pack contains 100 Grade 2, low-carbon steel hex nuts with coarse 3/8-16 threads. The listing gives a 9/16-inch wrench size and a 21/64-inch height. Unlike the locking options above, these are standard hex nuts rather than nylon-insert lock nuts or split washers.
Best for: Buyers who need a larger supply of ordinary coarse-thread nuts for general use. The material is zinc-finished steel rather than 304 stainless steel, so choose a stainless option if that material is required for your application.
Buying Guide: How To Choose 3/8 Split Hardware
Do you need a nut or a split lock washer?
A nut has internal threads and fastens onto a threaded bolt or rod. A split lock washer is a separate ring with a split; it sits under a nut or bolt head. Product listings sometimes group both types in the same kit, so check the included parts rather than relying on the phrase “split nuts.”
Which thread specification should you check?
For the listed threaded nuts, 3/8-16 means a 3/8-inch nominal diameter with 16 threads per inch. Match the nut to the bolt’s thread specification. A washer’s 3/8-inch size describes its fit category, but verify dimensions where clearance is important; the Neprift listing, for example, specifies a 0.37-inch inner diameter.
Should you choose stainless steel or zinc-finished steel?
Several choices here list 304 stainless steel, including the Vifmy and Swpeet products. Makers Bolt lists zinc-finished Grade 2 low-carbon steel. Select based on the material required for the job and the conditions it will face; the product details alone do not establish suitability for every environment.
Is a locking nut interchangeable with a split washer?
No. A nylon-insert lock nut uses an insert to create friction at the threads. A split lock washer is installed separately beneath a nut or bolt head. They are different components, so follow the hardware and assembly requirements for your project rather than treating them as identical.
Frequently Asked Questions
What does 3/8-16 mean on a nut?
It identifies a nominal 3/8-inch thread diameter and 16 threads per inch. Check the bolt specification to confirm that the threads match.
Are split nuts the same as split lock washers?
No. A split lock washer is a washer with a split, while a nut is threaded hardware. Search terminology can be imprecise, so check the product description and images.
Which option includes split lock washers and nuts?
Both Swpeet assortments include nuts, flat washers, and split lock washers. The 75-piece kit has 25 of each; the 45-piece kit has 15 of each.
Which product is only split lock washers?
The Neprift pack contains 30 3/8-inch split lock washers. It does not include nuts.
Do all the products use stainless steel?
No. Vifmy, both Swpeet kits, and Neprift list stainless steel components. Makers Bolt lists zinc-finished Grade 2 low-carbon steel nuts.