Hex Bolt

Hex Bolt – Product Details

JMIKS Fasteners supplies hex bolts in stainless steel SS 304, SS 316 and SS 202, and in mild steel and high tensile grades from 4.6 to 12.9. Sizes run from M3 to M36 and ¼” to 1-1/4″ BSW, in lengths from 6 mm to 250 mm, to DIN and IS standards. Send your size, grade and quantity for a quotation.

Specifications

Standard : DIN / IS
Size : Metric : M3 To M36 / BSW : ¼” to 1-1/4”
Material Grade: SS304 | SS316 | SS202
High Tensile Grade : 4.6 | 8.8 | 10.9 | 12.9
Length : 6mm to 250mm

Hex Bolt Types and Standards

A hex bolt has a six-sided head that is tightened with a spanner or socket. Two thread forms are common:

Half thread (partially threaded) hex bolts have a plain shank under the head, for joints that carry shear load. Common standards: DIN 931, ISO 4014 and IS 1364 (Part 1).
Full thread hex bolts (hex screws) are threaded up to the head, for clamping and general assembly. Common standards: DIN 933, ISO 4017 and IS 1364 (Part 2).

Hex Bolt Materials and Grades

Grade	Material	Typical use
SS 304 (A2)	Stainless steel, about 18% chromium and 8% nickel	General outdoor and indoor work, food and pharma equipment
SS 316 (A4)	Stainless steel with 2–3% molybdenum	Coastal, marine and chemical environments
SS 202	Lower-nickel stainless steel	Indoor and dry areas where cost matters
4.6	Mild steel, 400 MPa tensile strength	Light structures, sheds and general fabrication
8.8	Hardened and tempered carbon steel, 800 MPa	Machinery, structural steel and solar structures
10.9 / 12.9	Hardened and tempered alloy steel, 1000–1200 MPa	Heavy machinery and high-load joints

Not sure which grade you need? See our bolt grade chart and our SS 304 vs SS 316 vs SS 202 guide.

Where Hex Bolts Are Used

Steel structures, sheds and pre-engineered buildings
Solar panel mounting structures
Machinery, pumps and gearboxes
Electrical panels, transformers and switchgear
Pipelines, flanges and process plants
Automobile and tractor parts

Hex Bolt Size Chart

Common metric sizes with thread pitch, spanner size (across flats) and head height. ISO 4017 / ISO 4014 bolts use a smaller spanner size on M10, M12 and M14 than the older DIN 933 / DIN 931.

Size	Thread pitch	Spanner size ISO	Spanner size DIN	Head height
M6	1.0	10	10	4.0
M8	1.25	13	13	5.3
M10	1.5	16	17	6.4
M12	1.75	18	19	7.5
M14	2.0	21	22	8.8
M16	2.0	24	24	10.0
M20	2.5	30	30	12.5
M24	3.0	36	36	15.0
M30	3.5	46	46	18.7
M36	4.0	55	55	22.5

All dimensions in mm, for reference. Lengths from 6 mm to 250 mm.

Hex Bolt FAQs

What is the difference between DIN 931 and DIN 933 hex bolts?

DIN 931 bolts are partially threaded, with a plain shank under the head. DIN 933 bolts are threaded all the way to the head. Both have the same hexagon head.

Which hex bolt is best for outdoor use?

SS 304 suits most outdoor work. Near the sea or around chemicals, choose SS 316. Mild steel and high tensile bolts used outdoors are normally hot dip galvanized (HDG) or zinc plated.

What does 8.8 on a bolt head mean?

It is the property class. The first number multiplied by 100 gives the tensile strength in MPa (800 MPa). Multiplying the two numbers and then by 10 gives the yield strength (640 MPa).