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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Sofía Trivino Mejia
Natrona Heights, US
★★★★★ 5
Perfect size for laptop backpack!
Color: Champagne-upgrade, Size: 14 Inch, Color: Champagne-upgrade, Size: 14 Inch
Professional and stylish Perfect for my 12.5” laptop! I choose the one with 14inch and is perfect size, not small not big
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Reviewed in the United States on February 7, 2026
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Tracy
Bozeman, US
★★★★★ 5
Professional, functional, and cute!
Color: Pinkish Grey, Size: 14-Inch
I needed a backpack that looked professional and that wasn't massive. This fits my 15 inch laptop with room to spare. The back zipper portion is padded for extra laptop protection. I was surprised by the quality. It's my go-to bag for transporting my work stuff to and from the office.
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Reviewed in the United States on June 9, 2025
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Tr
Draper, US
★★★★★ 5
Great buy
Color: Pinkish Grey, Size: 14-Inch
Great backpack for computer. I like that I can transport my computer and other homework supplies in a small, fashionable backpack
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Reviewed in the United States on May 28, 2026
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Miss HLAvant
New York, US
★★★★★ 5
Perfect Small-ish Business Bag
Color: Apricot, Size: 14-Inch
I have been on the search for a small business bag, that can go on. top of my luggage as well as look nice in the office and at meetings. That will still hold all of my things while keeping me organized. So what fits, I can put my 12.9" iPad, with case and Magic Keyboard in the spot for a laptop. I can also put my 8x10 spiral bound planner, a notebook, mouse, small cable case, pencil case, water bottle and purse pouch with all my essentials. So my water bottle does not fit inside the side bottle pockets, so I do have to put it inside the bag it's self, but that's a no issue. The shoulder straps seem sturdy enough and the color beige/cream looks nice with my neutral wardrobe. Overall I'm happy with the purchase. We'll see how it travels over the next year as I have quite a bit of traveling and work do to offsite this year. j
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Reviewed in the United States on January 17, 2023
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FlyCoolChick
San Leandro, US
★★★★★ 4
Stylish, High-Quality Backpack. A Great Upgrade from My Usual Black Bags!
Color: Pinkish Grey, Size: 14-Inch
I’m really impressed with this backpack. I usually stick to black bags, but I decided to try something different, and I’m so glad I did. The color is beautiful—unique without being too loud—and adds a nice pop. The quality of the material feels top-notch. It’s sturdy yet lightweight, and the stitching and zippers seem very durable. Overall, this backpack feels well thought out in both design and function. Highly recommend if you’re looking for something professional, stylish, and practical.
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