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Industry Grade Guide

Steel for General Engineering
& Sub-Contract Machining.

The broadest sector in UK manufacturing — covering sub-contract machining, jig and fixture manufacture, general fabrication, precision turning and light to medium machinery. Grade selection here is driven by machinability, cost-effectiveness and the mechanical properties needed for the specific component. EN8 and EN19 are the workhorses; EN1A and EN1A Pb for automatic turning; EN3B for light-duty weldable work.

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Sector Overview

What General Engineering Requires from Steel Bar

Sub-contract machinists and general engineering shops have one priority above all others: getting parts off the machine correctly, quickly and profitably. That means starting material that machines cleanly, holds its dimensions during and after machining, and arrives in the specification they ordered — not what was available from a distributor who was running low.

The range of grades required by a typical sub-contract machine shop is wider than any other sector. In a single week, a busy CNC shop might process EN1A on the automatic lathe, EN8 on the turning centre, EN19T for a shaft order with a tensile certificate, and EN3B for a weldable bracket. Each needs to be right grade, right size, right tolerance, on time.

Key Grades

At a Glance.

EN1AFree-cutting — automatic turning, nuts, fittingsEN1A PbLeaded free-cutting — faster automatic turningEN3BMild steel — weldable, light-duty shaftsEN8Medium carbon — general shafts, spindles, keysEN8DMedium carbon to analysis — tooling, general turned

Full grade list below ↓

Shafts, Spindles & General Turned Components

EN8 (080M40) is the workhorse for general shafts and spindles — stronger than mild steel, machinable in both normalised and hardened & tempered condition, and available from stock in a comprehensive size range. For higher-stressed shafts, or where section size exceeds EN8's hardenability limit, EN19 (42CrMo4) provides significantly higher tensile strength and better deep-section hardening.

EN3B (070M20) suits light-duty shafts where strength requirements are modest and weldability is important. The bright drawn condition gives ready-to-machine dimensional accuracy to h9/h10/h11 tolerance per BS EN 10278 — reducing or eliminating preliminary turning for many components.

Recommended Grades
EN8 (080M40) Medium carbon. The default choice for general shafts, keys and machined parts. Flame hardenable to 50–55 HRC. EN19 (708M40 / 42CrMo4) Cr-Mo alloy. When EN8 isn't enough. High tensile, good hardenability to 65mm section. EN3B (070M20) Mild steel. Light-duty shafts, weldable assemblies, keys and pins.

High-Volume Automatic Turning & Fasteners

EN1A (230M07 / 11SMn30) is the standard grade for high-volume CNC turning and automatic lathe work — nuts, bolts, studs, fittings and any component produced in quantity where cycle time and surface finish matter more than strength. The free-cutting sulphur content breaks chips cleanly and dramatically extends tool life.

EN1A Pb (230M07Pb) adds lead for even faster cutting speeds — 25–35% improvement over non-leaded EN1A. Used where maximum productivity on automatic lathes is the priority. EN8M (212A42) provides a useful compromise — EN8-level strength with elevated sulphur for better machinability than standard EN8, used for high-volume fastener production where some tensile strength is required alongside rapid machining.

Recommended Grades
EN1A (230M07) Free-cutting. The automatic turning grade. Exceptional machinability, extended tool life. EN1A Pb (230M07Pb) Leaded. Even faster cutting speeds. For high-volume intricate automatic turned parts. EN8M (212A42) Free-cutting medium carbon. EN8 strength with better chip-breaking. Bolts and fasteners.

Tooling, Fixtures & Jig Manufacture

Jig and fixture manufacture often requires material that can be hardened locally — flame or induction hardened wear pads, hardened locating pins, case hardened buttons. EN8 (080M40) covers the majority of these requirements with flame hardening to 50–55 HRC.

For tooling blanks where moderate strength and good machinability are both required, EN8D (080A42) offers a cost-effective option where the full EN8 mechanical test certificate is not needed.

Recommended Grades
EN8 (080M40) Medium carbon. Flame hardenable wear pads and fixture components. EN8D (080A42) Medium carbon to analysis. Tooling blanks where full EN8 cert not required.
All Grades for General Engineering

Recommended Grades — Full List.

Click any grade for full data sheet, chemical composition, mechanical properties and heat treatment guidance.

EN1A 230M07 Free-cutting — automatic turning, nuts, fittings EN1A Pb 230M07Pb Leaded free-cutting — faster automatic turning EN3B 070M20 Mild steel — weldable, light-duty shafts EN8 080M40 Medium carbon — general shafts, spindles, keys EN8D 080A42 Medium carbon to analysis — tooling, general turned EN8M 212A42 Free-cutting medium carbon — fasteners, bolts EN9 070M55 High carbon — wear blades, springs EN19 42CrMo4 Cr-Mo alloy — higher tensile shafts S355 S355J2 Structural — fabricated frames, load-bearing

Not sure which grade is right? Call our sales team on 01623 687 660 — we can advise based on your component, loading and heat treatment requirements.

Common Questions

Frequently Asked.

EN8 (080M40) is the standard choice for most general engineering shafts — stronger than mild steel, machinable, and available in a comprehensive range of bright and black bar sizes. For shafts above 40mm diameter that need through-hardening, or where tensile strength above 700 N/mm² is required, specify EN19 (42CrMo4) instead.
EN1A (230M07) for maximum machinability. EN1A Pb (230M07Pb) where even faster cutting speeds are needed. EN8M (212A42) where you need EN8-level carbon content alongside improved chip-breaking. None of these grades are suitable for impact loading or welded assemblies.
Yes. EN 10204 3.1 material test certificates are available on all alloy grades from Parkside Steel. Call when ordering and we will ensure the correct documentation is supplied with the delivery.
Explore Further

Related Industries.

Automotive & Motorsport ► MRO & Maintenance ► Hydraulics & Pneumatics ►
Two operatives picking engineering steel bar from blue racking — Parkside Steel stockholding
Operative at full cantilever racking wall — depth of engineering steel bar stock visible

Talk to Us About Your General Engineering Requirements.

20+ grades in stock — cut to any length — 2–3 day turnaround. Our sales team understands engineering steel — not just the catalogue. Call with a grade, a component description, or a question.

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