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Bolts · Trade series (inch shoulder screws)

A2 (304) Stainless Steel Inch Slotted Shoulder Screws

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

A2 Stainless Steel Inch Slotted Shoulder Screws 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.

A2 (304) Stainless Steel Inch Slotted Shoulder Screws reference image

A2 Stainless Steel Inch Slotted Shoulder Screws combine the dimensional form of Trade series (inch shoulder screws) with the material properties of grade ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70: good general corrosion resistance, largely non-magnetic, service range approx. -200 °C to +400 °C, subject to the property class and the joint. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.

Why Choose A2 Stainless Steel for Inch Slotted Shoulder Screws

The most common stainless group for indoor and general outdoor fasteners. For inch slotted shoulder screws, this matters when good general corrosion resistance is the primary requirement.

Mechanical & Physical Properties

Grade designationISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70
Magnetic responseLargely non-magnetic
Service temperatureapprox. -200 °C to +400 °C, subject to the property class and the joint
Corrosion characteristicGood general corrosion resistance

Galvanic & Galling Considerations

Two important notes for stainless inch slotted shoulder screws: (1) stainless can gall on stainless threads under load — use a thread lubricant or anti-galling compound, especially for M6 and below; (2) when joined to aluminum or galvanized steel, stainless can drive galvanic corrosion of the less-noble metal in wet service — isolate with a coating or sleeve where appropriate.

Comparable Grades

For Inch Slotted Shoulder Screws, the alternative stainless grade is A4 (316). A2 (304) suits general indoor and outdoor service; A4 (316) adds molybdenum for marine and chloride environments. Where higher strength matters more than corrosion, switch to plated alloy-steel class 8.8 or 10.9.

Using Stainless Fasteners in Aluminum

Stainless steel is more noble than aluminum, so in the presence of an electrolyte — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. The effect is driven by the area ratio: a small stainless fastener in a large aluminum section is normally acceptable, while a large stainless fastener in thin aluminum is not. Where the joint is wet, isolate the two metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.

Sizes of Inch Slotted Shoulder Screws Available in A2 Stainless Steel

Shoulder diameter (in)Thread optionsShoulder length (in)Slot width (in)Slot depth (in)Material optionsThread class
1/8#4-40 / #6-321/8~1-1/20.047~0.0940.062~0.109303 or 416 stainless / alloy steel / brass2A
1/4#8-32 / #10-24 / #10-321/8~1-1/20.047~0.0940.062~0.109303 or 416 stainless / alloy steel / brass2A
3/81/4-20 / 5/16-181/8~1-1/20.047~0.0940.062~0.109303 or 416 stainless / alloy steel / brass2A
1/23/8-161/8~1-1/20.047~0.0940.062~0.109303 or 416 stainless / alloy steel / brass2A

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.

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 (Trade series (inch shoulder screws))

Shoulder diameter (in)Thread optionsShoulder length (in)Slot width (in)Slot depth (in)Material optionsThread class
1/8#4-40 / #6-321/8~1-1/20.047~0.0940.062~0.109303 or 416 stainless / alloy steel / brass2A
1/4#8-32 / #10-24 / #10-321/8~1-1/20.047~0.0940.062~0.109303 or 416 stainless / alloy steel / brass2A
3/81/4-20 / 5/16-181/8~1-1/20.047~0.0940.062~0.109303 or 416 stainless / alloy steel / brass2A
1/23/8-161/8~1-1/20.047~0.0940.062~0.109303 or 416 stainless / alloy steel / brass2A

Applications & Industries

Inch Slotted Shoulder Screws are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from 1/8 to 1/2 (screw size).

Industries that specify Inch Slotted Shoulder Screws

  • Light machinery Wear-resistant pivot hardware assembled with a simple slot driver.
  • Linkage mechanisms Slotted-head shoulder screws used as pivots and bearing shoulders.
  • Tooling fixtures Replaceable guide and stop points in jigs.
  • Camera and instrument mounts Controlled shoulder length where axial position matters.
  • Energy & infrastructure Tower, pipework, switchgear and plant fixings specified for long service life and inspectable joints.
  • Maintenance & MRO Stocked replacements matched to an existing property class, thread and finish.

Typical applications

  • keeping the mating part on the shoulder instead of the threaded section
  • locating a rotating or sliding part on a defined cylindrical shoulder
  • selecting shoulder diameter and length separately from the thread
  • using the slot for low-profile manual assembly
  • joints where the property class is stated on the drawing
  • clamping two machined faces to a calculated preload

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 use the slot as a high-torque structural drive; it is a compact head feature for the shoulder assembly.
  • 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 Inch Slotted Shoulder 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

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.

Are A2 Stainless Steel Inch Slotted Shoulder Screws magnetic?

A2 Stainless Steel Inch Slotted Shoulder Screws are largely non-magnetic.

What corrosion resistance do A2 Stainless Steel Inch Slotted Shoulder Screws offer?

A2 Stainless Steel Inch Slotted Shoulder Screws provide good general corrosion resistance with a service range of approx. -200 °C to +400 °C, subject to the property class and the joint.

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.