A true 5/8-inch bolt has a 5/8-inch nominal thread diameter, but none of the listed products is identified as a 5/8-inch fastener. The closest SAE options are a 3/8-inch bolt and an assortment that goes up to 1/2 inch; the other kits use metric or 5/16-inch hardware. Use the comparison below to identify a kit for adjacent sizes or routine projects, and verify the diameter, thread pitch, and length before ordering a fastener for a 5/8-inch application.
| Product | Size system and range | Best for |
|---|---|---|
| Fullerkreg hex bolts | 3/8-16, listed bolt | Single-size stainless hardware |
| Quibbay SAE assortment | 1/4 to 1/2 inch | Common SAE repairs and range of sizes |
| Fgruh M5 kit | M5 metric | Small metric installations |
| Metric screw assortment | M2, M3, M4, M5 | Electronics and small projects |
| 5/16-inch stainless sets | 5/16-18 x 5 inches | Longer 5/16-inch assemblies |
Fullerkreg 3/8-16 Stainless Steel Hex Bolts
These fully threaded hex-head bolts are listed as 3/8-16 and made from 18-8 stainless steel. The hexagonal head is intended for installation with a spanner, and the product description says length is measured from under the head. Stainless steel may suit projects where chemical resistance is useful, though the listing notes the material may be mildly magnetic.
Best for: Buyers who need a specific 3/8-16 stainless bolt rather than a 5/8-inch bolt. It is selected as a clearly specified SAE alternative with a stated material and thread size. Limitation: Its diameter is 3/8 inch, not 5/8 inch, and no nut is included in the provided product details.
Quibbay SAE Bolts And Nuts Assortment
This 924-piece assortment includes SAE hex bolts in 1/4-20, 5/16-18, 3/8-16, and 1/2-13 sizes, with varying listed lengths. It also contains hex nuts, lock washers, and flat washers in a compartmentalized case. The product description identifies the hardware as carbon steel and describes the assortment as Grade 8.
Best for: DIYers or repair users who need several common SAE sizes organized in one kit. It is the closest listed assortment for someone seeking SAE hardware, but its largest stated diameter is 1/2 inch. Limitation: It does not include 5/8-inch bolts or nuts, so it cannot fill a 5/8-inch requirement.
Fgruh M5 Socket Screw Assortment
This 272-piece metric kit contains M5-0.8 socket-head bolts in eight lengths from 8 mm to 35 mm, plus nuts, flat washers, spring washers, and a mini wrench. The listing specifies 12.9 alloy steel and an oil-free black galvanized finish. It describes the kit for routine installations, repairs, 3D printing, RC cars, and small electronics.
Best for: Buyers whose project calls for M5 metric socket screws and matching small hardware. It is included as a useful small-fastener kit, not as a substitute for an SAE 5/8-inch bolt. Limitation: M5 is a metric size and is far smaller than a 5/8-inch-diameter fastener.
Metric M2 To M5 Screw Assortment
The product name describes a 2,205-piece assortment of M2, M3, M4, and M5 metric machine screws, nuts, and washers. It is presented as a black zinc-plated alloy-steel kit for 3D printing, DIY, and electronics. Detailed counts, lengths, and other specifications were not provided here, so check the product listing for those details before choosing it.
Best for: Users who need a broad range of small metric fasteners for bench work or electronics. It is selected for variety, not for a 5/8-inch application. Limitation: The listed metric sizes do not include a 5/8-inch bolt, and the available details do not establish the exact contents by size.
5/16-18 Stainless Bolt And Nut Sets
This listing specifies 5/16-18 UNC bolts with full thread coverage, paired with hex nuts, flat washers, and lock washers. The product details state that the fasteners are 304 (18-8) stainless steel with a black oxide coating. The title and feature text differ on the stated set quantity, so confirm package contents in the listing before purchase.
Best for: Projects requiring long 5/16-inch stainless bolt-and-washer assemblies. It is selected because it includes matching nuts and washers and clearly states its thread size. Limitation: 5/16 inch is not 5/8 inch; the listed size also should be verified against the intended nut and application.
Buying Guide: How To Choose A 5/8 Bolt And Nut
What does 5/8 inch mean?
For a bolt, 5/8 inch normally refers to the nominal thread diameter. It does not specify the bolt length or thread pitch. A product labeled 5/16 inch is half that nominal diameter, while 3/8 inch and 1/2 inch are also smaller than 5/8 inch.
Which thread details should you check?
Match the thread system, pitch, and diameter. SAE coarse-thread hardware may be marked with a format such as diameter and threads per inch, while metric hardware uses millimeters and a metric pitch. Do not assume a nut will fit just because its nominal diameter appears close; incompatible thread standards can bind or damage threads.
How should you choose length and material?
Measure the needed grip length and account for the material being joined, washers, and nut engagement. For the Fullerkreg listing, length is measured from under the head. Choose material based on the environment and project requirements, and verify load or strength needs from a reliable specification rather than assuming that a kit suits every structural use.
Is an assortment better than a single-size set?
An assortment is practical when a project uses several listed sizes and having spare hardware is useful. A single-size package can reduce sorting when every fastener must match. For an exact 5/8-inch repair, neither an assortment that stops at 1/2 inch nor a smaller metric or 5/16-inch kit is an appropriate match.
Frequently Asked Questions
Does any listed product include a 5/8-inch bolt?
No. The listed SAE products specify 3/8 inch, up to 1/2 inch, or 5/16 inch. The remaining kits use metric sizes.
Is a 5/8-inch bolt the same as a 5/8-11 bolt?
No. Five-eighths inch identifies the nominal diameter. “-11” indicates 11 threads per inch, so it adds a thread-pitch specification.
Can I use a 1/2-inch nut on a 5/8-inch bolt?
No. The nominal sizes differ, so the nut is not the matching size. Use a nut with the same diameter and compatible thread pitch and standard.
What should I verify before ordering?
Confirm nominal diameter, thread pitch, thread standard, bolt length, material, and whether the package includes a matching nut and washers. For load-bearing uses, confirm that the fastener specifications meet the project requirements.