Best Steel Square Head Bolts in 2026

Daisy
Last Updated: Jul 17, 2026

At a Glance: Our Top Picks for Steel Square Head Bolts

3/8X6 Carriage Bolt
#TOP1
3/8X6 Carriage Bolt
7.4
PM SCORE
Hillman 812584 3/8X3-1/2 Carriage Bolt, 3/8 x 3-1/2-Inch, Galvanized, 50
#TOP2
Hillman 812584 3/8X3-1/2 Carriage Bolt, 3/8 X 3-1/2-Inch,
7.3
PM SCORE
1/2X10 Carriage Bolt
#TOP3
1/2X10 Carriage Bolt
7.1
PM SCORE

* PickSmartly editors independently research, review, and endorse the top products through comprehensive data analysis. We may earn a commission for qualifying purchases made through our product links.

Summary of the Best Steel Square Head Bolts of 2026

Market Overview
Steel Square Head Bolts Reviewed
  • Reviews Analyzed: 330 Items
  • PM Avg. Rating: 5.1 / 10
22 Products Evaluated
  • Highest Price: $104.99
  • Lowest Price: $21.71
  • Avg. Price: $42.88
#TOP1

3/8X6 Carriage Bolt

HILLMAN
812593
4.60 X 7.00 X 3.50 Inches
8.55 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

Hillman 812584 3/8X3-1/2 Carriage Bolt, 3/8 X 3-1/2-Inch, Galvanized, 50

HILLMAN
812584
5.40 X 4.10 X 3.40 Inches
5.45 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP3

1/2X10 Carriage Bolt

HILLMAN
812635
13.40 X 4.80 X 4.60 Inches
11.90 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP4

3/8X5 Carriage Bolt

HILLMAN
7812590
3.30 X 4.40 X 6.90 Inches
7.00 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP5

Hillman Group Galvanized Carriage Bolt 1/2” X 4”, 25 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, For Wood And Metal, No Washer Needed, Rust-Resistant (812620) 25 Pack

HILLMAN
812620
5.20 X 4.40 X 3.40 Inches
5.71 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP6

Hillman Group Galvanized Carriage Bolt 5/16” X 6”, 50 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, For Wood And Metal, No Washer Needed, Rust-Resistant (812563)

HILLMAN
812563
7.10 X 4.60 X 3.30 Inches
5.84 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Gatzies 9.78

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP7

Hillman Group Galvanized Carriage Bolt 1/2” X 9”, 25 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, For Wood And Metal, No Washer Needed, Rust-Resistant (812633)

HILLMAN
812633
4.50 X 4.80 X 13.20 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP8

Hillman Group Galvanized Carriage Bolt 1/2” X 3-1/2”, 25 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, Wood And Metal, No Washer Needed, Rust-Resistant (812617)

HILLMAN
812617
3.20 X 4.30 X 4.40 Inches
5.80 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP9

Hillman Group Galvanized Carriage Bolt 1/4” X 4”, 100 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, Wood And Metal, No Washer Needed, Rust-Resistant (812524)

HILLMAN
812524
7.00 X 4.60 X 3.40 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP10

Hillman Group Galvanized Carriage Bolt 3/8” X 10”, 50 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, Wood And Metal, No Washer Needed, Rust-Resistant (812599)

HILLMAN
812599
13.30 X 4.80 X 4.70 inches
2.01 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP11

1/2X3 Carriage Bolt

HILLMAN
812614
3.40 X 4.60 X 6.90 inches
9.00 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Gatzies 9.78

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP12

1/2X7 Carriage Bolt

HILLMAN
812627
3.60 X 5.10 X 10.10 Inches
0.27 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP13

Hillman Group Galvanized Carriage Bolt 5/16” X 4-1/2”, 50 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, Wood And Metal, No Washer Needed, Rust-Resistant (812558)

HILLMAN
812558
5.40 X 4.20 X 3.40 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP14

5/16X2 Carriage Bolt

HILLMAN
812545
0.50 X 0.50 X 5.80 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP15

5/16X3-1/2 Carr Bolt

HILLMAN
812554
3.30 X 4.30 X 4.30 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP16

Hillman Group Galvanized Carriage Bolt 5/8” X 10”, 25 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, Wood And Metal, No Washer Needed, Rust-Resistant (812653)

HILLMAN
812653
4.40 X 5.00 X 13.30 Inches
21.30 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

Hillman Group Galvanized Carriage Bolt 1/4” X 2-1/2”, 100 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, Wood And Metal, No Washer Needed, Rust-Resistant (812515)

HILLMAN
812515
4.60 X 4.30 X 3.40 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP18

3/8X4 Carriage Bolt

HILLMAN
812587
6.90 X 4.60 X 3.40 Inches
6.00 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP19

Hillman Group Galvanized Carriage Bolt 5/16” X 5”, 50 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, Wood And Metal, No Washer Needed, Rust-Resistant (812560)

HILLMAN
812560
6.90 X 4.50 X 3.40 Inches
0.09 Pounds
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP20

3/8X7 Carriage Bolt

HILLMAN
812594
10.00 X 5.10 X 3.60 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
FASTENER DEPOT, LLC 9.76

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP21

Hillman Group Galvanized Carriage Bolt 5/8” X 6”, 25 Count, Blunt Point, Alloy Steel, Self-Locking Round Head Fasteners, Wood And Metal, No Washer Needed, Rust-Resistant (812647)

HILLMAN
812647
10.00 X 5.30 X 3.80 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

#TOP22

3/8X5-1/2 Carriage Bolt

HILLMAN
812591
3.40 X 4.60 X 6.90 Inches
SELLER SELLER SCORE AMAZON FULFILLED PRIME FREE SHIPPING
Amazon.com 9.68

Features

Carriage Bolts are designed to fasten a wooden face to either wood or metal

Flat head provides a semi-flush finish to applications

The heads is designed to eliminate the need for a washer

Square underside of the head is self locking to eliminate the need for a driving tool

Galvanized finish is perfect for rust prevention

Top 10 square head bolts Brands on Amazon

Here is the list of top-rated brands that were evaluated by PM.

Brand Count
Hillman 22

Top 10 square head bolts Brands Pie Chart


We've carried out a comprehensive analysis of 330 reviews on square head bolts, using our selection criteria to identify the best options in the fasteners. Our findings reveal that most customers typically select square head bolts priced around $42.88, with top brands including hard-to-find fastener and small parts and uxcell

Our team of expert editors reviewed these high-quality items and handpicked the top 22 square head bolts for your consideration. We've also done extensive research on numerous sellers, identifying the best ones in the fasteners category. These include and amazon.com and amadeo city .

We are dedicated to assisting our users in finding the right bolts Products based on their needs, saving them considerable time when choosing which square head bolts to buy. We take pride in the number of satisfied users we've helped through our thorough and insightful reviews.