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Bolts · ISO 8676 / DIN 961

A4 (316) Stainless Steel Fine-Thread Hex Head Cap Screws, Fully Threaded

Mechanical properties, corrosion behaviour and the full dimensional range for this grade.

A4 Stainless Steel Fine-Thread Hex Head Cap Screws, Fully Threaded are supplied to ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80. Corrosion behaviour is superior, including marine and chloride environments, the material is largely non-magnetic, and the usable service range is approx. -200 °C to +400 °C, subject to the property class and the joint. In practice this grade is specified for marine, coastal and chemical applications.

Grade
ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80
Corrosion resistance
Superior, including marine and chloride environments
Magnetic response
Largely non-magnetic
Service temperature
approx. -200 °C to +400 °C, subject to the property class and the joint

Property values are typical for the grade. Certified mechanical test data is available on request for production orders.

A4 (316) Stainless Steel Fine-Thread Hex Head Cap Screws, Fully Threaded reference image

Fine-Thread Hex Head Cap Screws, Fully Threaded manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to ISO 8676 / DIN 961. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.

Why Choose A4 Stainless Steel for Fine-Thread Hex Head Cap Screws, Fully Threaded

Specified for marine, coastal and chemical applications. For fine-thread hex head cap screws, fully threaded, this matters when superior, including marine and chloride environments is the primary requirement.

Mechanical & Physical Properties

Grade designationISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80
Magnetic responseLargely non-magnetic
Service temperatureapprox. -200 °C to +400 °C, subject to the property class and the joint
Corrosion characteristicSuperior, including marine and chloride environments

Corrosion Behavior in Service

A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Fine-Thread Hex Head Cap Screws, Fully Threaded in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.

Comparable Grades

For Fine-Thread Hex Head Cap Screws, Fully Threaded, the alternative stainless grade is A2 (304). A2 (304) covers general indoor and outdoor service. A4 (316) adds molybdenum, which is what buys the chloride resistance for marine and de-icing-salt exposure. Where strength matters more than corrosion, plated alloy steel in class 8.8 or 10.9 is the swap to make.

Using Stainless Fasteners in Aluminum

Expect the aluminum to corrode, not the fastener — stainless sits higher in the galvanic series, so the aluminum is the one that gives up material. A small fastener in a thick section spreads the loss over a large area and is usually fine; a large fastener in thin sheet concentrates it and is not. Keep water out of the joint, or isolate the two metals with a nylon or coated washer and a sealant.

Sizes of Fine-Thread Hex Head Cap Screws, Fully Threaded Available in A4 Stainless Steel

SizeTypePitch P (mm)c (mm)dw (mm)Width across corners e (mm)Head height k (mm)r (mm)Width across flats s (mm)Length range l (mm)Reference standard
M8x1Hex head screw1.00.311.614.385.30.413.08~120ISO 8676 / DIN 961
M10x1Hex head screw1.00.315.618.96.40.417.08~150ISO 8676 / DIN 961
M10x1.25Hex head screw1.00.315.618.96.40.417.08~150ISO 8676 / DIN 961
M12x1.25Hex head screw1.250.317.421.17.50.619.010~180ISO 8676 / DIN 961
M12x1.5Hex head screw1.50.317.421.17.50.619.010~180ISO 8676 / DIN 961
(M14x1.5)Hex head screw1.50.320.524.498.80.622.010~200ISO 8676 / DIN 961
M16x1.5Hex head screw1.50.422.526.7510.00.624.012~200ISO 8676 / DIN 961
(M18x1.5)Hex head screw1.50.425.330.1411.50.627.018~200ISO 8676 / DIN 961
(M18x2)Hex head screw2.00.425.330.1411.50.627.018~200ISO 8676 / DIN 961
M20x1.5Hex head screw1.50.428.233.5312.50.830.018~200ISO 8676 / DIN 961
M20x2Hex head screw1.50.428.233.5312.50.830.018~200ISO 8676 / DIN 961
(M22x1.5)Hex head screw1.50.430.035.7214.00.832.018~200ISO 8676 / DIN 961
(M22x2)Hex head screw2.00.430.035.7214.00.832.018~200ISO 8676 / DIN 961
M24x1.5Hex head screw1.50.433.639.9815.00.836.020~200ISO 8676 / DIN 961
M24x2Hex head screw2.00.433.639.9815.00.836.020~200ISO 8676 / DIN 961
(M27x2)Hex head screw2.00.438.045.217.01.041.020~200ISO 8676 / DIN 961
M30x2Hex head screw2.00.442.750.8518.71.046.030~200ISO 8676 / DIN 961
(M33x2)Hex head screw2.00.446.655.3721.01.050.035~200ISO 8676 / DIN 961
M36x3Hex head screw3.00.451.160.7922.51.055.035~200ISO 8676 / DIN 961
(M39x3)Hex head screw3.00.555.966.4425.01.060.035~200ISO 8676 / DIN 961
M42x3Hex head screw3.00.559.971.326.01.265.040~200ISO 8676 / DIN 961
(M45x3)Hex head screw3.00.564.776.9528.01.270.040~200ISO 8676 / DIN 961
M48x3Hex head screw3.00.569.482.630.01.675.045~200ISO 8676 / DIN 961
(M52x3)Hex head screw3.00.574.288.2533.01.680.050~200ISO 8676 / DIN 961
M8x1Hex head screws with fine pitch thread1.00.311.6314.385.30.413.016~80ISO 8676 / DIN 961
M10x1Hex head screws with fine pitch thread1.00.314.6317.776.40.415.020~100ISO 8676 / DIN 961
(M10x1.25)Hex head screws with fine pitch thread1.250.314.6317.776.40.415.020~100ISO 8676 / DIN 961
M12x1.5Hex head screws with fine pitch thread1.50.316.6320.037.50.618.025~120ISO 8676 / DIN 961
(M12x1.25)Hex head screws with fine pitch thread1.250.316.6320.037.50.618.025~120ISO 8676 / DIN 961
(M14x1.5)Hex head screws with fine pitch thread1.50.319.6423.368.80.621.030~140ISO 8676 / DIN 961

Dimensions are independent of the material: every size above is available in A4 Stainless Steel.

Custom manufacturing · Made to drawing

Need this bolt in a grade that is not listed?

A4 Stainless Steel is one of the grades the catalog describes. Material and finish are usually what drives a special — a grade the standard part is not stocked in, or a coating chosen against a salt-spray figure instead of a default. Made by cold heading or hot forging.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

Custom bolt manufacturingSend a drawing

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Dimensioned line drawing of M8x1 Fine-Thread Hex Head Cap Screws, Fully Threaded to ISO 8676 / DIN 961. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.
Type
Hex head screw
Pitch P (mm)
1.0
c (mm)
0.3
dw (mm)
11.6
Width across corners e (mm)
14.38
Head height k (mm)
5.3
r (mm)
0.4
Width across flats s (mm)
13.0
Length range l (mm)
8~120
Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (ISO 8676 / DIN 961)

SizeTypePitch P (mm)c (mm)dw (mm)Width across corners e (mm)Head height k (mm)r (mm)Width across flats s (mm)Length range l (mm)Reference standard
M8x1Hex head screw1.00.311.614.385.30.413.08~120ISO 8676 / DIN 961
M10x1Hex head screw1.00.315.618.96.40.417.08~150ISO 8676 / DIN 961
M10x1.25Hex head screw1.00.315.618.96.40.417.08~150ISO 8676 / DIN 961
M12x1.25Hex head screw1.250.317.421.17.50.619.010~180ISO 8676 / DIN 961
M12x1.5Hex head screw1.50.317.421.17.50.619.010~180ISO 8676 / DIN 961
(M14x1.5)Hex head screw1.50.320.524.498.80.622.010~200ISO 8676 / DIN 961
M16x1.5Hex head screw1.50.422.526.7510.00.624.012~200ISO 8676 / DIN 961
(M18x1.5)Hex head screw1.50.425.330.1411.50.627.018~200ISO 8676 / DIN 961
(M18x2)Hex head screw2.00.425.330.1411.50.627.018~200ISO 8676 / DIN 961
M20x1.5Hex head screw1.50.428.233.5312.50.830.018~200ISO 8676 / DIN 961
M20x2Hex head screw1.50.428.233.5312.50.830.018~200ISO 8676 / DIN 961
(M22x1.5)Hex head screw1.50.430.035.7214.00.832.018~200ISO 8676 / DIN 961
(M22x2)Hex head screw2.00.430.035.7214.00.832.018~200ISO 8676 / DIN 961
M24x1.5Hex head screw1.50.433.639.9815.00.836.020~200ISO 8676 / DIN 961
M24x2Hex head screw2.00.433.639.9815.00.836.020~200ISO 8676 / DIN 961
(M27x2)Hex head screw2.00.438.045.217.01.041.020~200ISO 8676 / DIN 961
M30x2Hex head screw2.00.442.750.8518.71.046.030~200ISO 8676 / DIN 961
(M33x2)Hex head screw2.00.446.655.3721.01.050.035~200ISO 8676 / DIN 961
M36x3Hex head screw3.00.451.160.7922.51.055.035~200ISO 8676 / DIN 961
(M39x3)Hex head screw3.00.555.966.4425.01.060.035~200ISO 8676 / DIN 961
M42x3Hex head screw3.00.559.971.326.01.265.040~200ISO 8676 / DIN 961
(M45x3)Hex head screw3.00.564.776.9528.01.270.040~200ISO 8676 / DIN 961
M48x3Hex head screw3.00.569.482.630.01.675.045~200ISO 8676 / DIN 961
(M52x3)Hex head screw3.00.574.288.2533.01.680.050~200ISO 8676 / DIN 961
M8x1Hex head screws with fine pitch thread1.00.311.6314.385.30.413.016~80ISO 8676 / DIN 961
M10x1Hex head screws with fine pitch thread1.00.314.6317.776.40.415.020~100ISO 8676 / DIN 961
(M10x1.25)Hex head screws with fine pitch thread1.250.314.6317.776.40.415.020~100ISO 8676 / DIN 961
M12x1.5Hex head screws with fine pitch thread1.50.316.6320.037.50.618.025~120ISO 8676 / DIN 961
(M12x1.25)Hex head screws with fine pitch thread1.250.316.6320.037.50.618.025~120ISO 8676 / DIN 961
(M14x1.5)Hex head screws with fine pitch thread1.50.319.6423.368.80.621.030~140ISO 8676 / DIN 961
M16x1.5Hex head screws with fine pitch thread1.50.422.4926.7510.00.624.035~160ISO 8676 / DIN 961
(M18x1.5)Hex head screws with fine pitch thread1.50.425.3430.1411.50.627.035~180ISO 8676 / DIN 961
M20x1.5Hex head screws with fine pitch thread1.50.428.1933.5312.50.830.040~200ISO 8676 / DIN 961
(M20x2)Hex head screws with fine pitch thread2.00.428.1933.5312.50.830.040~200ISO 8676 / DIN 961
(M22x1.5)Hex head screws with fine pitch thread1.50.431.7137.7214.00.834.045~220ISO 8676 / DIN 961
M24x2Hex head screws with fine pitch thread2.00.433.6139.9815.00.836.040~200ISO 8676 / DIN 961
(M27x2)Hex head screws with fine pitch thread2.00.438.045.217.01.041.055~260ISO 8676 / DIN 961
M30x2Hex head screws with fine pitch thread2.00.442.7550.8518.71.046.040~200ISO 8676 / DIN 961
(M33x2)Hex head screws with fine pitch thread2.00.446.5555.3721.01.050.065~360ISO 8676 / DIN 961
M36x3Hex head screws with fine pitch thread3.00.451.1160.7922.51.055.040~200ISO 8676 / DIN 961
(M39x3)Hex head screws with fine pitch thread3.00.555.8666.4425.01.060.080~380ISO 8676 / DIN 961
M42x3Hex head screws with fine pitch thread3.00.559.9571.326.01.265.090~420ISO 8676 / DIN 961
(M45x3)Hex head screws with fine pitch thread3.00.564.776.9528.01.270.090~440ISO 8676 / DIN 961
M48x3Hex head screws with fine pitch thread3.00.569.4582.630.01.675.0100~480ISO 8676 / DIN 961
(M52x4)Hex head screws with fine pitch thread4.00.574.288.2533.01.680.0100~500ISO 8676 / DIN 961
M56x4Hex head screws with fine pitch thread4.00.578.6693.5635.02.085.0120~500ISO 8676 / DIN 961
(M60x4)Hex head screws with fine pitch thread4.00.583.4199.2138.02.090.0120~500ISO 8676 / DIN 961
M64x4Hex head screws with fine pitch thread4.00.588.6104.8640.02.095.0130~500ISO 8676 / DIN 961

Materials & Grades

Select a material class to see the grades we supply it in. Each designation is listed with its ISO/EN, AISI/SAE, JIS and GB equivalents.

Stainless Steel38 Carbon Steel66 Alloy Steel41 Bearing Steel5 Spring Steel25 Aluminum and Aluminum Alloys21 Brass17 Bronze11 Copper8 Titanium and Titanium Alloys18 Nickel and Nickel Alloys22 Iron-Nickel and High-Temperature Alloys10 Tool Steel and Specialty Hardened Steel9 Structural and Construction Steel9

Stainless Steel

Austenitic Stainless Steel

  • A1 AISI 303 · SAE 303 · SUS303 · EN 1.4305 · X8CrNiS18-9
  • A2 AISI 304 · SAE 304 · SUS304 · EN 1.4301 · X5CrNi18-10 · 06Cr19Ni10
  • 304L AISI 304L · SUS304L · EN 1.4307 · X2CrNi18-9 · 022Cr19Ni10
  • 302 AISI 302 · SUS302 · EN 1.4310
  • 305 AISI 305 · SUS305 · EN 1.4303
  • A4 AISI 316 · SAE 316 · SUS316 · EN 1.4401 · X5CrNiMo17-12-2 · 06Cr17Ni12Mo2
  • 316L AISI 316L · SUS316L · EN 1.4404 · X2CrNiMo17-12-2 · 022Cr17Ni12Mo2
  • 321 AISI 321 · SUS321 · EN 1.4541 · X6CrNiTi18-10
  • 310 / 310S AISI 310 · AISI 310S · SUS310S · EN 1.4845
  • 302HQ AISI 302HQ
  • A3
  • A5
  • 347 AISI 347 · SUS347 · EN 1.4550 · X6CrNiNb18-10
  • 309 / 309S AISI 309 · AISI 309S · SUS309S

Martensitic Stainless Steel

  • AISI 410 SUS410 · EN 1.4006 · X12Cr13 · 12Cr13
  • AISI 420 SUS420J1 · SUS420J2 · EN 1.4021 · EN 1.4028 · 20Cr13 · 30Cr13
  • AISI 431 SUS431 · EN 1.4057 · X17CrNi16-2
  • C1
  • C3
  • C4
  • AISI 440A
  • AISI 440B
  • AISI 440C SUS440C · EN 1.4125

Ferritic Stainless Steel

  • AISI 430 SUS430 · EN 1.4016 · X6Cr17 · 10Cr17
  • F1
  • AISI 434
  • AISI 444

Precipitation-Hardening Stainless Steel

  • 17-4 PH AISI 630 · UNS S17400 · SUS630 · EN 1.4542 · X5CrNiCuNb16-4
  • 15-5 PH UNS S15500
  • 17-7 PH UNS S17700

Duplex and Super Duplex Stainless Steel

  • Duplex 2205 UNS S31803 · UNS S32205 · EN 1.4462
  • Super Duplex 2507 UNS S32750 · EN 1.4410
  • D2
  • D4
  • D6
  • D8
  • Lean Duplex 2101 UNS S32101
  • Super Duplex S32760 UNS S32760 · EN 1.4501

Carbon Steel

Low-Carbon Steel

  • SAE 1006
  • SAE 1008
  • SAE 1010
  • SAE 1018
  • SAE 1020
  • Q195
  • Q235
  • SAE 1012
  • SAE 1015
  • Q215
  • ML08
  • ML08Al
  • ML10
  • ML15
  • ML20
  • SWRCH6A
  • SWRCH8A
  • SWRCH10A
  • SWRCH12A
  • SWRCH15A
  • SWRCH18A

Medium-Carbon Steel

  • SAE 1035
  • SAE 1045
  • S45C
  • C45
  • SAE 1030
  • SAE 1040
  • SAE 1050
  • 30
  • 35
  • 40
  • 45
  • 50
  • S35C
  • S40C
  • S50C
  • C35
  • C40

High-Carbon Steel

  • SAE 1060
  • SAE 1070
  • 65Mn
  • SAE 1065
  • SAE 1075
  • SAE 1080
  • SAE 1085
  • SAE 1090
  • SAE 1095
  • 60
  • 65
  • 70
  • 75
  • 80
  • 85

Cold-Heading Steel

  • SWRCH22A
  • 10B21
  • SWRCH22K
  • SWRCH25K
  • SWRCH30K
  • SWRCH35K
  • SWRCH40K
  • ML20Mn
  • ML25
  • ML30
  • ML35
  • ML40
  • 15B25

Alloy Steel

Chromium Steel

  • 40Cr
  • 45Cr
  • AISI 5140
  • SAE 5140
  • AISI 5120
  • SAE 5120
  • SCr420
  • SCr440

Chromium-Molybdenum Steel

  • 35CrMo
  • 42CrMo
  • AISI 4140
  • SCM435
  • SCM440
  • 42CrMo4
  • 30CrMo
  • AISI 4130
  • SAE 4130
  • SAE 4140
  • AISI 4142
  • AISI 4145
  • SCM415
  • SCM420
  • SCM445
  • EN 1.7220
  • EN 1.7225
  • 25CrMo4
  • 34CrMo4

Nickel-Chromium-Molybdenum Steel

  • AISI 4340
  • SAE 4340
  • 40CrNiMo
  • SNCM439
  • EN 1.6511
  • 36CrNiMo4

Boron Alloy Steel

  • 10B22
  • 10B21
  • 15B21
  • 15B25
  • 20MnTiB
  • 20Mn2B
  • 35VB
  • 40MnB

Bearing Steel

Bearing Steel

  • GCr15
  • AISI 52100 SAE 52100 · UNS G52986
  • SUJ2
  • 100Cr6 EN 1.3505
  • GCr15SiMn

Spring Steel

Carbon Spring Steel

  • SAE 1065
  • SAE 1070
  • SAE 1075
  • SAE 1080
  • SAE 1095
  • 65
  • 70
  • 75
  • 80
  • 65Mn

Silicon-Manganese Spring Steel

  • 60Si2Mn
  • 60Si2MnA
  • SUP6
  • SUP7

Chromium-Vanadium Spring Steel

  • 50CrVA
  • SAE 6150
  • AISI 6150
  • SUP10

Stainless Spring Steel

  • AISI 301
  • SUS301
  • EN 1.4310
  • AISI 302
  • AISI 304
  • AISI 316
  • 17-7 PH

Aluminum and Aluminum Alloys

Commercially Pure Aluminum

  • 1050
  • 1060
  • 1070
  • 1100

2xxx Series Aluminum

  • 2024
  • 2011
  • 2014
  • 2017

5xxx Series Aluminum

  • 5052
  • 5083
  • 5754

6xxx Series Aluminum

  • 6061
  • 6061-T6
  • 6063
  • 6082
  • 6082-T6

7xxx Series Aluminum

  • 7075
  • 7075-T6
  • 7005
  • 7050
  • 7075-T73

Brass

Free-Cutting Brass

  • C36000
  • H62
  • HPb59-1
  • C3601
  • C3602
  • C3604
  • CuZn36Pb3
  • CuZn39Pb3
  • EN CW614N
  • EN CW617N
  • H65

Lead-Free Brass

  • C69300
  • C27450
  • CW510L
  • CW511L

Naval Brass

  • C46400
  • CuZn39Sn1

Bronze

Silicon Bronze

  • C65500
  • C65100
  • C65600

Phosphor Bronze

  • C51000
  • C52100
  • CuSn6
  • CuSn8

Aluminum Bronze

  • C95400
  • C95500
  • C63000
  • CuAl10Ni5Fe4

Copper

Copper

  • C11000
  • T2
  • C10100
  • C10200
  • C12200
  • T1
  • TU1
  • TU2

Titanium and Titanium Alloys

Commercially Pure Titanium

  • Grade 2
  • Grade 1
  • Grade 3
  • Grade 4
  • TA1
  • TA2
  • TA3

Alpha-Beta Titanium Alloys

  • Grade 5
  • Ti-6Al-4V
  • TC4
  • UNS R56400

Low-Interstitial Grade

  • Grade 23
  • Ti-6Al-4V ELI
  • UNS R56407

Other Titanium Fastener Alloys

  • Ti-6Al-6V-2Sn
  • Ti-6Al-2Sn-4Zr-2Mo
  • Beta-C titanium
  • Ti-10V-2Fe-3Al

Nickel and Nickel Alloys

Commercially Pure Nickel

  • Nickel 200
  • UNS N02200
  • Nickel 201
  • UNS N02201

Inconel Alloys

  • Inconel 625 UNS N06625
  • Inconel 718 UNS N07718
  • Inconel 600 UNS N06600
  • Inconel 601 UNS N06601
  • Inconel 686 UNS N06686
  • Inconel X-750 UNS N07750

Monel Alloys

  • Monel 400 UNS N04400
  • Monel K-500 UNS N05500

Hastelloy Alloys

  • Hastelloy C-276 UNS N10276
  • Hastelloy C-22 UNS N06022
  • Hastelloy B-2 UNS N10665
  • Hastelloy B-3 UNS N10675
  • Hastelloy X UNS N06002

Other Nickel Alloys

  • Alloy 20 UNS N08020
  • Alloy 625
  • Alloy 718
  • Alloy 825 UNS N08825
  • Alloy 925 UNS N09925

Iron-Nickel and High-Temperature Alloys

A286

  • A-286
  • UNS S66286
  • EN 1.4980

Invar

  • Invar 36
  • Alloy 36
  • UNS K93600
  • FeNi36

Alloy 42

  • Alloy 42
  • UNS K94100
  • FeNi42

Tool Steel and Specialty Hardened Steel

Tool Steel and Specialty Hardened Steel

  • AISI D2
  • AISI H13
  • SKD11
  • Cr12MoV
  • AISI O1
  • AISI A2
  • AISI S7
  • SKD61
  • 9CrSi

Structural and Construction Steel

Structural and Construction Steel

  • ASTM A36
  • Q235B
  • Q355B
  • S355JR
  • Q235C
  • Q355C
  • S235JR
  • S275JR
  • S355J2

Applications & Industries

What Fine-Thread Hex Head Cap Screws are specified for, industry by industry. Stocked from M8x1 to M64x4.

Industries that specify Fine-Thread Hex Head Cap Screws

  • Hydraulic equipment fine-thread bodies.
  • Aerospace ground support fine-thread fixings.
  • Automotive fine-thread tapped holes.
  • Machine tools fine adjustment and stronger threads in thin walls.
  • Machine building & OEM The default fastener on production equipment: covers, brackets, motor mounts and sub-assemblies tightened to a specified torque.
  • Automotive & transport Chassis, driveline and body fixings that see vibration and are assembled to a controlled preload.

Typical applications

  • resisting loosening with a smaller helix angle
  • fitting fine-thread tapped holes
  • stronger thread engagement in thin sections
  • finer preload adjustment
  • assemblies that are dismantled for service and re-torqued
  • joints where the property class is stated on the drawing

Service conditions to specify against

Marine and coastal
Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
High load
Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
Torque and preload
The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.

Where to use something else

  • Do not assume a fine thread fits a coarse hole of the same diameter; check the pitch before ordering.
  • Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.

Full application guide: where Fine-Thread Hex Head Cap Screws are used, how to specify them, and the cases they are wrong for

Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

Can A4 Stainless Steel replace plated alloy steel structurally?

Only at the standard strength classes — A2-70 / A4-80 are roughly equivalent to class 7 steel; A4-100 reaches class 8.8. For class 10.9 or 12.9 strength, plated alloy steel is required.

Are A4 Stainless Steel Fine-Thread Hex Head Cap Screws, Fully Threaded magnetic?

A4 Stainless Steel Fine-Thread Hex Head Cap Screws, Fully Threaded are largely non-magnetic.

What corrosion resistance do A4 Stainless Steel Fine-Thread Hex Head Cap Screws, Fully Threaded offer?

A4 Stainless Steel Fine-Thread Hex Head Cap Screws, Fully Threaded provide superior, including marine and chloride environments with a service range of approx. -200 °C to +400 °C, subject to the property class and the joint.

Should I choose A4 Stainless Steel or A2 (304) for Fine-Thread Hex Head Cap Screws, Fully Threaded?

For Fine-Thread Hex Head Cap Screws, Fully Threaded, A4 Stainless Steel suits general indoor and outdoor use; A2 (304) is preferred for marine, coastal and chemical environments. Choose by corrosion exposure first.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.