Hillman 5/16 in. Diameter x 3-1/2 in. Length Heat-Treated Steel Hex Head Cap Screw, 50-Pack
SKU: 33821358236

Hillman 5/16 in. Diameter x 3-1/2 in. Length Heat-Treated Steel Hex Head Cap Screw, 50-Pack

Sale price$43.19 Regular price$47.99
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Description

Hillman 5/16 in. Diameter x 3-1/2 in. Length Heat-Treated Steel Hex Head Cap Screw, 50-PackHillman Grade 8 Hex Head Cap Screws, 5 16 in. x 3 1 2 in., 50 Pack Heavy duty Grade 8 hex head cap screws engineered from heat treated steel for high strength fastening. Ideal for machinery, automotive, and structural applications where a durable, partially threaded bolt is required. Key Features: Grade 8 Strength: Heat treated steel provides superior tensile strength for demanding applications Washer Face Head: Built in washer face under head helps

Hillman Grade 8 Hex Head Cap Screws, 5/16 in. x 3-1/2 in., 50-Pack

Heavy-duty Grade 8 hex head cap screws engineered from heat-treated steel for high-strength fastening. Ideal for machinery, automotive, and structural applications where a durable, partially threaded bolt is required.


Key Features:

  • Grade 8 Strength: Heat-treated steel provides superior tensile strength for demanding applications
  • Washer Face Head: Built-in washer face under head helps improve load distribution and sealing
  • Partially Threaded Shank: Offers better shear strength and alignment in assemblies
  • Coarse Thread: USS coarse thread for quick starts and strong hold in tapped holes or with nuts
  • Bulk 50-Pack: Convenient boxed quantity for shop, jobsite, or maintenance stock

Specifications Table:

Specification Details
Diameter 5/16 inch
Length 3-1/2 inch
Material Steel
Grade Grade 8
Finish Heat-treated yellow dichromate-style
Thread Type Coarse (USS)
Head Type Hex head with washer face
Threading Partially threaded shank
Number in Package 50 pack
Packaging Type Boxed
Unit of Measure Listed by Source Metric (listing label)

Frequently Asked Questions (FAQ):

Q: Are these fully or partially threaded?
A: They are partially threaded along the shank for added shear strength.


Q: What finish do these have?
A: They feature a heat-treated yellow dichromate-style finish for extra wear resistance.


Q: What thread type are they?
A: USS coarse thread.


Q: What tools are needed for installation?
A: Tighten with a wrench or compatible socket; a drill/driver with socket adapter may also be used.


Q: What size are these bolts?
A: 5/16-inch diameter by 3-1/2-inch length.


Industrial Strength With a Sleek, Purposeful Edge

These hex cap screws bring a crisp, engineered precision to any utilitarian vignette—think open-shelf workshops and garage studios. The faceted head and clean shank create a subtle rhythm that feels both rugged and refined. Style them with exposed hardware on custom shelving or welded frames to celebrate honest materials. Their performance pedigree makes them a quiet luxury in hardworking spaces.


Upgrade your hardware bin with Grade 8 strength—add this 50-pack to your cart for reliable, long-lasting fastening.

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 33821358236

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Sami 🛒
Port Orchard, US
★★★★★ 5
Rustic Wall Shelves That Just Work
Size: 17inch, Color: Black
I bought these six floating shelves to add some storage and a cohesive look to a few walls around the house. The set has a rustic real wood vibe with an industrial edge, and the black finish keeps things feeling clean and understated. It turned out to be a practical way to create space without committing to a bulky cabinet, and I appreciated having multiple pieces to arrange in different rooms. Installation was straightforward. The package includes 12 brackets, wall anchors and screws, plus clear directions, so I could get them up without much hassle. It takes about eight minutes to mount each shelf, and the hardware feels solid. The shelves can hold around 20 pounds each, which is plenty for everyday items like books, a plant, an alarm clock, or framed photos. In use, the look is exactly what I wanted: sturdy, simple, and able to blend with existing decor across the bedroom, bathroom, kitchen, and living room. The real wood surface and the exposed metal brackets give a cohesive, rustic vibe that elevates plain walls and makes it easy to rotate items in and out. One small note is that the boards are 17 inches long and about an inch thick, so planning spacing and wall space matters a bit. The brackets being visible is part of the look, not a flaw, but it means accurate mounting is important. Overall I am very pleased with the set and it earns a solid five stars.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 17, 2026
C
Verified Purchase
Carolyn Flory
Draper, US
★★★★★ 5
Great shelves
Size: 17inch, Color: Light Walnut, Size: 17inch, Color: Light Walnut
I love how these look in the nook in my bathroom. I needed 6 inch shelves and this was way easier than ripping 8 inch from the hardware store
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 30, 2026
C
Verified Purchase
Cynthia perez
Grantham, US
★★★★★ 5
Great
Size: 36inch, Color: Light Walnut, Size: 36inch, Color: Light Walnut
Got the job done very light weight but durable great condition installation was super easy
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Reviewed in the United States on April 29, 2026
V
Verified Purchase
Vanesa French
Boise, US
★★★★★ 4
Not a bad buy
Size: 36inch, Color: Light Walnut, Size: 36inch, Color: Light Walnut
Very Light weight, they look great though. Fairly easy to put together. Came with all parts I’ll be it scattered and the screws don’t look sturdy but I won’t be using the ones that it came with. Overall, fair price, quality is fair as well.
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Reviewed in the United States on January 16, 2026
B
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Becky Z.
Louisville, US
★★★★★ 5
Love these shelves!
Size: 48inch, Color: Light Walnut
These are incredible for the price! Feel & look like wood. Easy-ish to install - just take your time, measure twice & use a level. Very sturdy! Great hardware & instructions. Now my daughter wants some for her apt.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 22, 2025

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