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What is an annular cutter?

An annular cutter is a hollow cutting tool that removes material only at the perimeter of the hole, requiring less cutting force and power than a conventional twist drill. This enables faster drilling, improved hole accuracy with minimal burrs and longer tool life.

Euroboor annular cutters are primarily used with magnetic drilling machines. They can however also be used with compatible cordless and corded portable drilling systems, stationary drilling machines and other suitable drilling equipment. 

The range includes HSS, HSS-Co and TCT annular cutters for different materials, diameters and cutting depths.

Which annular cutter do you need?

Cutter type

Best suited for

Main advantage

HSS

General metalworking in mild and structural steel, aluminium, copper and plastics

Versatile and accurate

HSS-Co

Repetitive drilling and more demanding materials

Greater hardness and heat resistance

TCT

Hardened, stainless and high-tensile-strength steel

Extremely hard, durable cutting teeth

HSS annular cutters

High Speed Steel (HSS) annular cutters are a versatile choice for everyday fabrication and general metalworking. Their tooth geometry and spiral flutes support a fast, stable cut with effective chip removal and a smooth hole finish.

Euroboor HSS annular cutters feature an additional landing on the outside, helping them cut more accurately with less friction. The precision-ground inner surface gives the slug room to expand, helping prevent it from binding inside the cutter.

HSS-Co annular cutters

HSS-Co annular cutters are manufactured from M35 High Speed Steel containing 5% cobalt. The added cobalt increases hardness and helps the cutting edges retain their performance at higher temperatures.

Fully ground flutes support efficient chip removal, making HSS-Co a strong choice for harder materials, repetitive drilling and applications requiring higher cutting performance.

TCT annular cutters

Tungsten Carbide Tipped annular cutters are designed for demanding drilling applications. Euroboor TCT cutters use durable carbide cutting teeth for materials such as HARDOX, stainless steel, high-tensile-strength steel and railway track.

Their spiral flute geometry supports effective chip removal, while the tooth positioning helps limit heat development. TCT cutters are also well suited to larger diameters and greater cutting depths.

How do you choose the correct size and cutting depth?

The cutter diameter determines the size of the hole. The required cutting depth depends on the thickness of the workpiece.

Always select an annular cutter with sufficient cutting depth to pass completely through the material. Euroboor cutters are available in a wide range of diameters and cutting depths for both plate and pipe applications.

Which shank does an annular cutter use?

Euroboor annular cutters are fitted as standard with high-precision Weldon shanks. Depending on the cutter size and specification, two shank diameters are used:

  • 19.05 mm (3/4")
  • 31.75 mm (1 1/4")

Cutters with a double-shank design (WelNit) are also available. These can be used on machinery requiring either a Weldon or Nitto fitment, increasing compatibility across different magnetic drilling machines.

For Euroboor TCT cutters, diameters up to 60 mm use a 19.05 mm WelNit shank. Diameters from 61 mm use a 31.75 mm Weldon shank.

Why is the pilot pin important?

A correctly fitting pilot pin supports accurate drilling and smooth operation. It performs three essential functions:

  • It centres the cutter before drilling begins.
  • It controls the flow of cutting lubricant.
  • It ejects the slug after the hole is completed.

The pilot pin must match the cutter diameter and cutting depth. An incorrect or poorly fitting pilot pin can affect centring, lubricant flow and slug ejection.

Why do cooling and lubrication matter?

Metal drilling generates friction and heat, which can affect cutting performance, hole quality and tool life. Using the correct cutting lubricant reduces friction, improves cutting efficiency, and helps the cutter run more smoothly with less vibration.

Effective cooling helps control heat build-up in both the cutter and the workpiece, supporting consistent performance and reliable slug ejection. This reduces stress on the cutter and drilling machine while maintaining drilling accuracy.

For annular cutters, internal cooling and lubrication provide the most efficient solution by delivering lubricant through the pilot pin directly to the cutting zone, exactly where it is needed.

The result?

  • Reduced friction and heat generation
  • Improved hole quality and drilling accuracy
  • More reliable slug ejection
  • Less wear on the cutter and drilling machine
  • Significantly longer tool life and lower operating costs

With the right cooling and lubrication, annular cutters can achieve higher productivity, more consistent performance and substantially extended service life.

What RPM should you use?

The correct spindle speed depends on the cutter diameter, cutter type and material being drilled. In practice, RPM is determined by the recommended cutting speed for the material and the diameter of the annular cutter.

As a rule, larger diameter cutters require lower RPM, while smaller cutters can operate at higher RPM. TCT annular cutters typically run at higher cutting speeds than HSS cutters when drilling the same material.

Using the recommended spindle speed helps control heat generation, maintain cutting performance, improve hole quality, and maximise cutter life. Running too fast can cause excessive heat and premature wear, while running too slowly can reduce productivity and cutting efficiency. The Euroboor Cutting Speed Calculator provides a recommended RPM based on the cutter type, diameter, and material, helping you achieve optimal drilling performance and tool life.

Calculadora de velocidade de corte

Calculadora de velocidade de corte
para brocas anulares

- mm / - inch

 

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