Precision Engineering London

Stainless Steel Machining

Over the years we have evolved into to a specialist stainless steel machining operation with many customers in the food, power, marine and water industries requiring complete machined parts from a range of stainless steel alloys.


Effective machining of stainless steel requires a combination of expertise, experience, high powered machine stations and exacting feeds. Principle considerations are detailed below:

  • High powered machinery that can be run effectively at 75% is required.
  • Clean working environments to avoid contamination.
  • Attention to work piece holding to prevent chatter, plastic deformation and movement.
  • High speed tool steel or carbide tooling used and sharpened regularly
  • Consistent and directed cutting fluids

Typical problems that can occur with stainless steel machining include:

  • Workpiece glazing
  • Dull surface finish
  • Built up edge
  • Depth of cut notching

These are generally caused by the tendency for stainless steel to rapidly work harden, its brittle nature, the stringy chips that are formed and the difficulty to make small depths of cuts, to name a few.

As specialists in this field we are of course quite able to predict and avoid these issues.


We work with all types of stainless steel (Austentic, Ferratic, Martenstic and Duplex), both standard and enhanced machineability types including:

Austentic 304
Ferratic 430




Material Properties

Below are a range of material properties for a range of stainless steel types:

  • 304 Low carbon steel with excellent corrosive resistance.
  • 316 Best corrosion resistance of the standard stainless steels. Resists pitting and most chemicals. High temperature strength.
  • 316F Free machining version of 316.
  • 303 Free machining type used in corrosive atmospheres, strong chemical solutions, many organic chemicals, most dyes, nitric acid and foods.
  • 303se Free machining stainless steel with superior surface finish than 303.
  • 430 The most widely used of the nonhardenable types of chromium stainless steel. Good mechanical properties and heat resistance. Resistant to nitric acid, sulfur gases, and many organic chemicals, including foods.
  • 430F Free machining version of 430.
  • 410 Low-cost general-purpose stainless steel that is heat-treatable. Used where corrosion is not severe.
  • 416 Free machining version of 410 with corrosion resistance to food acids, basic salts, water, and most atmospheric corrosion products.
  • 420 Higher carbon version of 410 and can be can be hardened by heat treatment.
  • 420F Free machining version of 420.
  • 440C High -carbon stainless steel. Can be heat-treated for high strength and high hardness. Corrosion resistant only when hardened.
  • 440F Free machining version of 440C.
  • 319 Excellent strength and corrosion resistance.
  • Duplex Dual phase materials with austenite and ferrite offering excellent strength and corrosion resistance.


We can arrange for stainless steel passivation where required for enhanced corrosion protection. Pickling can also be undertaken. Cleaning is generally required to remove the free iron from the machine tool as well as other sources such as welding and general handling.


JS Precision Engineering Ltd - Spelthorne Lane - Ashford - Middlesex - TW15 1UX
Tel: 01784 246 726 - Fax: 01784 423 213 - E-Mail:

Martenstic Stainless Steel Machining - CNC Milling - CNC Turning - 4 Axis Machining - Keywaying - Prototypes - Grinding
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