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The Difference Between Round Bar and Precision Ground Bar

Metal can be produced in a wide variety of sizes and shapes. These shapes can often look similar – such as pipe and tube – but have very different attributes and applications.

This is also true for a couple of round shapes: round bar and precision ground bar.

The Difference Between Round Bar and Precision Ground Bar

Round Bar

Round bar is exactly as it sounds; a long, cylindrical metal bar. Round bar is available in a variety of metals including black steel, bright steel, stainless steel, aluminium, engineering steel, brass and more; and in many different diameters ranging from 1/4″ up to 24”.

Steel Round Bars

Steel round bars are available in black or bright steel. Black steel round bar is typically used for applications like construction where finish and precise dimensions aren’t a priority. Conversely, bright steel round bar is used for applications where a superior surface finish and exact dimensions are essential. Some common applications of steel round bar include frameworks, supports, braces, shafts, and axles.

Stainless Steel Round Bars

Stainless steel round bars are highly corrosion resistant. The stainless steel will tolerate high levels of acidity and can be used in chlorine bearing environments or alkaline solutions.

Aluminium Round Bars

Aluminium round bars possess light weight and strong corrosion resistance, while being easy to machine and cut. Common applications of aluminium round bar include supports, trim, shaft, braces, pins, and dowels.

Brass Round Bars

Brass round bars are used when strength, electrical conductivity, corrosion resistance, and spark resistance are important. Brass is easy to machine and has an attractive sheen when polished. Some examples of brass bar applications are marine hardware, instruments, fasteners and fittings.

Precision Ground Bar

Precision Ground Bar, also known as ‘Turned Ground and Polished’ shafting, refers to round bars made with fine precision and high-quality steel. They are polished to ensure flawless and perfectly straight surfaces. The manufacturing process is designed for extremely close tolerances for surface finish, roundness, hardness, and straightness which ensures a long service life with reduced maintenance.

Precision ground bar is commonly used often used in applications that require high accuracy, such as weather measuring devices, laboratory tools, high-speed motor shafts, drive shafts, pump shafts, and ball bushings. In these scenarios, the bar is often required to rotate at high speeds. Thus extreme straightness is critical to prevent unwanted vibration and wear on bearings.

Precision ground bar is manufactured through induction hardening.

Induction hardening

Induction hardening is a non-contact heating process which uses electromagnetic induction to produce the required heat. The steel is placed into a strong alternating magnetic field which causes an electric current to flow through the metal, generating heat. During this process the core of the steel remains unaffected and retains its physical properties. The steel is then quenched in water, oil, or a special polymer which causes the surface layer to form a martensitic structure which is extremely hard.

Metal Supermarkets


Metal Supermarkets is the world’s largest small-quantity metal supplier with 125 brick-and-mortar stores across the US, Canada, and United Kingdom. We are metal experts and have been providing quality customer service and products since 1985.

At Metal Supermarkets, we supply a wide range of metals for a variety of applications. Our stock includes: mild steel, stainless steel, aluminium, tool steel, engineering steel, brass, bronze and copper.

We carry a wide range of shapes including: bars, tubes, sheets and plates. We can cut metal to your exact specifications.

Visit one of our 8 locations in the United Kingdom today.

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