Standoffs & Spacers · Trade series (fully threaded standoff caps)

A2 (304) Stainless Steel Fully-Threaded Standoff Caps

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

A2 Stainless Steel Fully-Threaded Standoff Caps are supplied to ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70. Corrosion behaviour is good general corrosion resistance, 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 the most common stainless group for indoor and general outdoor fasteners.

Grade: ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70
Corrosion resistance: Good general corrosion resistance
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.

Material specification page for fully-threaded standoff caps in A2 Stainless Steel. Covers the grade designation (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to Trade series (fully threaded standoff caps).

Why Choose A2 Stainless Steel for Fully-Threaded Standoff Caps

The most common stainless group for indoor and general outdoor fasteners. For fully-threaded standoff caps, this matters when good general corrosion resistance is the primary requirement.

Mechanical & Physical Properties

Grade designation	ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70
Magnetic response	Largely non-magnetic
Service temperature	approx. -200 °C to +400 °C, subject to the property class and the joint
Corrosion characteristic	Good general corrosion resistance

Corrosion Behavior in Service

A2 (304) gives excellent atmospheric and most-water corrosion resistance and is the most common stainless for Fully-Threaded Standoff Caps in indoor and general outdoor service. In chloride-bearing environments (marine air, road salt, swimming pools) consider stepping up to A4 (316).

Comparable Grades

For Fully-Threaded Standoff Caps, the alternative stainless grade is A4 (316). 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 Fully-Threaded Standoff Caps Available in A2 Stainless Steel

Thread size	Outside diameter (in)	Cap height (in)	Thread length (in)	Material	Form
4-40	1/4	1/4	3/8	zinc-plated brass	fully threaded cap
6-32	1/4	1/4	3/8	zinc-plated brass	fully threaded cap
8-32	1/4	1/4	3/8	zinc-plated brass	fully threaded cap
10-32	1/4	1/4	3/8	zinc-plated brass	fully threaded cap

Technical Drawing

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Specification

Item / category Standard Size(s) Material / finish Quantity

Business Information

Company * Contact Name * Email * Phone (with country code) Country / Region

Notes

Dimensions & Specifications (Trade series (fully threaded standoff caps))

Thread size	Outside diameter (in)	Cap height (in)	Thread length (in)	Material	Form
4-40	1/4	1/4	3/8	zinc-plated brass	fully threaded cap
6-32	1/4	1/4	3/8	zinc-plated brass	fully threaded cap
8-32	1/4	1/4	3/8	zinc-plated brass	fully threaded cap
10-32	1/4	1/4	3/8	zinc-plated brass	fully threaded cap

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

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

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

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

Structural and Construction Steel

ASTM A36
Q235B
Q355B
S355JR
Q235C
Q355C
S235JR
S275JR
S355J2

Applications & Industries

Fully-Threaded Standoff Caps are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from 4-40 to 10-32 (nominal diameter).

Industries that specify Fully-Threaded Standoff Caps

Prototype fixtures 4-40 through 10-32 sizes close off unused standoff ends.
Electronics enclosures Threaded caps finish a standoff and protect the open thread.
Instrument panels Zinc-plated brass covers a small exposed thread without adding a large head.
Display hardware The cap form keeps debris out of a spacer assembly.
Enclosures & panels Spacing a fascia, guard or label plate off the surface behind it.
Instruments & controls Internal mounting where the gap is part of the design.

Typical applications

matching 4-40 through 10-32 to the standoff
finishing the exposed end of a threaded standoff
protecting the thread from debris and contact
selecting 1/4 in cap diameter and 3/8 in thread length
stacking boards at a repeatable pitch
setting and holding a fixed gap between two boards or panels

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.

Where to use something else

Do not use a standoff cap as a load-bearing nut; its purpose is thread protection and finish.

Full application guide: where Fully-Threaded Standoff Caps 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.

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.
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.
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.
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

Is A2 Stainless Steel food-grade?

A2 (304) is widely accepted for food contact in non-chloride environments; A4 (316) is preferred where chlorides are present.

Can A2 Stainless Steel Fully-Threaded Standoff Caps be used with aluminum?

Yes, but stainless drives mild galvanic corrosion of aluminum in wet service — isolate with a coating, sleeve or paint, or accept the trade-off if the joint is dry and indoor.

What's the service temperature limit for A2 Stainless Steel?

The practical service range is approx. -200 °C to +400 °C, subject to the property class and the joint.

Can A2 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.

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.