Stainless Steel Carriage Bolt Technical Specifications

Stainless Steel Carriage Bolt - Grade 202, 304, 316 - A2, A2-70

A Carriage Bolt (also called a Round Head Square Neck Bolt) is a type of fastener commonly used in wood-to-wood or wood-to-metal applications. It is known for its smooth, rounded head and square neck that prevents the bolt from turning once installed.

DIN 603
Size	Length
Size	F/T	H/T
M5	16-40	35-60
M6	16-40	35-60
M8	20-50	40-80
M10	20-60	45-100
M12	20-70	55-100

ANSI B 18.5
Size	Length
Size	F/T	H/T
1/4"	5/8" - 1 3/4"	1 1/2" - 2 1/2"
5/16"	3/4" - 2 3/4"	1 1/2" - 3 "
3/8"	3/4" - 2 3/4"	1 1/2" - 3 "

Carriage Bolt Technical Specifications (DIN 603 / ISO 8677 - Metric)

Nominal Diameter (d)	Pitch (P)	Head Diameter (dk)	Head Height (k)	Square Neck Width (a)	Neck Height (m)	Standard Length Range (L)
M5	0.8 mm	13.55 – 14.1 mm	3.3 mm	5.52 – 5.7 mm	3.7 mm	16 – 60 mm
M6	1.0 mm	16.55 – 17.1 mm	3.88 mm	6.52 – 6.7 mm	4.7 mm	16 – 60 mm
M8	1.25 mm	20.65 – 21.2 mm	5.38 mm	8.52 – 8.7 mm	6.4 mm	20 – 150 mm
M10	1.5 mm	24.65 – 25.2 mm	6.38 mm	10.52 – 10.7 mm	8 mm	25 – 200 mm
M12	1.75 mm	30.65 – 31.2 mm	7.38 mm	12.52 – 12.7 mm	9.5 mm	30 – 250 mm
M16	2.0 mm	38.8 – 40.0 mm	8.8 mm	16.62 – 16.9 mm	12.5 mm	40 – 300 mm
M20	2.5 mm	49.2 – 50.8 mm	10.2 mm	20.7 – 21.1 mm	16 mm	50 – 300 mm

Head Type: Round, dome-shaped
Neck Type: Square section just below the head
Drive Type: No drive on the head (non-slotted)
Material Options: Mild steel, stainless steel, galvanized steel
Thread Type: Partially or fully threaded shank
Common Grades: Grade 2, Grade 5, Stainless Steel 304/316
All dimensions are approximate and may vary slightly based on manufacturer tolerance.
Thread length is typically partial for longer bolts; shorter bolts may be fully threaded.
Head diameter and square neck size allow the bolt to self-lock in wood without turning.

A Carriage Bolt is a round-headed bolt with a square neck under the head. It is inserted into a pre-drilled hole, and the square neck grips into the material (usually wood) to keep the bolt from rotating when a nut is tightened on the opposite end.

Tensile Strength

≥700 MPa

Yield Strength

≥1100 MPa

Elongation

≥12%

Hardness Max

250 HB

Materials

Stainless Steel

Steel Grade

Finishing

Polished
Geomet
Dacromet
Teflon
Hot-Dip Galvanzing
Zinc (Yellow, White, Blue)
Black Qxide

Thread

Standards

Round Head

The polished, curved top adds a polished touch while also reducing the risk of snagging or harm, especially in busy spots.

Square Neck

The square section beneath the head is specifically designed to securely grip onto the material, commonly wood, while tightening.

Threaded Shank

The bolt features a threaded shank which is usually only partially threaded. This shank stretches from the square neck to accommodate a nut.

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