Hillman 3/8 in. x 3-1/2 in. Zinc-Plated Steel Carriage Bolt, Coarse Thread, 50-Pack
SKU: 20168103579

Hillman 3/8 in. x 3-1/2 in. Zinc-Plated Steel Carriage Bolt, Coarse Thread, 50-Pack

Sale price$35.99 Regular price$39.99
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Description

Hillman 3/8 in. x 3-1/2 in. Zinc-Plated Steel Carriage Bolt, Coarse Thread, 50-PackHillman 3 8 in. x 3 1 2 in. Zinc Plated Carriage Bolts (50) Durable zinc plated steel carriage bolts for fastening wood to wood or metal. Coarse thread, round head design with square neck resists spinning and installs cleanly for a semi flush finish. Key Features: Rugged Construction: Zinc plated steel provides corrosion resistance for indoor and general purpose use Secure Hold: Square neck under the round head locks into wood to prevent turning

Hillman 3/8 in. x 3-1/2 in. Zinc-Plated Carriage Bolts (50)

Durable zinc-plated steel carriage bolts for fastening wood to wood or metal. Coarse-thread, round-head design with square neck resists spinning and installs cleanly for a semi-flush finish.


Key Features:

  • Rugged Construction: Zinc-plated steel provides corrosion resistance for indoor and general-purpose use
  • Secure Hold: Square neck under the round head locks into wood to prevent turning during tightening
  • Clean Finish: Low-profile dome head eliminates the need for a washer in many applications
  • Coarse Thread: SAE coarse thread for quick assembly and strong grip
  • Project-Ready Pack: 50-piece box in 3/8 in. diameter by 3-1/2 in. length

Specifications Table:

Specification Details
Diameter 3/8 inch
Length 3-1/2 inch
Material Steel
Finish Zinc Plated
Thread Type Coarse (SAE)
Head Style Round head with square neck (carriage bolt)
Package Quantity 50
Brand Hillman
Item/SKU 240174

Frequently Asked Questions (FAQ):

Q: What materials can these carriage bolts fasten?
A: They are commonly used to fasten wood to wood or wood to metal frames.


Q: Are nuts and washers included?
A: No, this listing is for carriage bolts only; purchase compatible 3/8 in. nuts and washers separately if needed.


Q: Are these suitable for outdoor use?
A: Zinc plating offers basic rust resistance but is best for interior or sheltered applications; consider hot-dip galvanized or stainless for harsh outdoor environments.


Q: What thread type do they have?
A: SAE coarse thread.


Q: What is the grade and material?
A: Made from steel; grade information varies by source—use for general-purpose fastening.


Polished Utility with a Clean, Minimal Profile

The rounded dome of this carriage bolt brings a subtle, tailored finish to built-ins and custom millwork. I love the way the square neck tucks in, keeping the face pristine while delivering a firm, no-spin hold. Style it on bench slats or garden gate frames for a refined, hardware-as-detail moment. It’s the quiet, functional luxury that completes a thoughtfully crafted piece.


Equip your next build with these zinc-plated carriage bolts and enjoy a clean look with reliable holding power—add the 50-pack to your cart now.

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: 20168103579

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Verified Purchase
David D.k
Pawtucket, US
★★★★★ 5
Finally a mount for my truck!
2015 Toyota Tacoma Prerunner. I've tried many different mounts - ones that stuck to the dash, stuck to the windshield, one that mounted in the cup holder in the console. They all were bad in their own way. This Offroam mount finally got it right. Easy installation - and when I say SOLID hold I mean it. No movement, no rattle, do creaking sound, etc, etc. I was very skeptical of the one-handed use getting the phone in and out but it's really a genius design. Seriously - I just got it, so can't really speak to longevity yet. Judging by the design and quality of parts, I'll say it will be the last mount I ever purchase for this truck. Pay the extra, and be happy.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 12, 2026
S
Verified Purchase
SamsMommy
Lowell, US
★★★★★ 5
Great Quality, Perfect Fit
2015 Tacoma. This fit perfectly and is solid. Last/Different one I had on another vehicle broke one of my vent dividers. That can't happen with this design. Worth the money. Would absolutely recommend.
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Reviewed in the United States on April 3, 2026
D
Verified Purchase
David
Bozeman, US
★★★★★ 5
Well build and functions nicely
The products build quality is excellent; in fact, its far superior to this product's competitor, "Batdiary". This mount stays locked in place when i use one hand to mount my phone or remove it. Also, the internal mechanism is much nicer than the Batdiary one and feels like it has tighter and more accurate machining tolerances which should prevent it from rattling like its competitor's did after a couple weeks use. I highly recommend this product, it is worth the high price tag!
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Reviewed in the United States on November 6, 2025
H
Verified Purchase
Hawapino
Lowell, US
★★★★★ 4
Buy once, cry once
This Offroam phone mount is not the cheapest option, but it is easily the most functional and sturdy one available, especially for second-generation Toyota Tacomas. I went through several plastic phone mounts before this and should have bought this one from the start to save both money and frustration. Installation was very simple, and it is even easier to use day to day. I like that this mount uses adjustable arms to grip the phone rather than relying on MagSafe. It keeps my phone secure even on rough terrain and offers plenty of flexibility for positioning the phone exactly where you want it.
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Reviewed in the United States on January 25, 2026
J
Verified Purchase
Jason Lefebvre
Draper, US
★★★★★ 5
Top notch mount with high build quality
I love it when I take a chance and spend some extra money hoping for a quality product - and it actually pans out. I bought this for my 2nd gen Toyota Tacoma (2014). The install was fast. Instructions were clear. The mount is ROCK solid and has two points of articulation so I can position my phone well. I couldn't ask for a better product. The price I paid was a little steep for a mount, but if you demand quality then look no further.
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Reviewed in the United States on October 21, 2025

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