M4P by Bernardo MR20S Twist Drill Bit Sharpener: Precise Sharpening of Drill Bits from 2 to 20 mm

The M4P by Bernardo MR20S twist drill bit sharpener is a compact and efficient machine designed for sharpening metal drill bits from 2 to 20 mm in diameter. It restores the cutting edges of worn drill bits, helps maintain an appropriate drill point geometry and extends the useful life of drilling tools.

Particularly suitable for mechanical workshops, metalworking professionals, maintenance departments and users of pillar drills or drilling and milling machines, the M4P MR20S drill bit sharpener provides a practical solution for the regular maintenance of twist drill bits.

Thanks to its 2 to 20 mm sharpening capacity, it can accommodate a wide range of diameters, from smaller drill bits used for precision work to larger tools commonly employed in metal fabrication workshops.

Its adjustable drill point angle from 90° to 135° allows the sharpening geometry to be adapted to the characteristics of the drill bit and the intended drilling application.

The machine also features a drill point thinning device, particularly useful for improving point centring and reducing the axial force required during drilling.

Equipped with a 120 W motor and a grinding wheel operating at 4400 rpm, the MR20S is designed to deliver fast, accurate and repeatable sharpening results.

A Metal Drill Bit Sharpener for Diameters from 2 to 20 mm

The M4P by Bernardo MR20S is designed for sharpening two-flute twist drill bits with diameters ranging from 2 to 20 mm.

This extended sharpening range is one of the main advantages of this model. It allows users to maintain both smaller drill bits used for general drilling operations and larger-diameter tools commonly employed with pillar drills and drilling and milling machines.

During use, the cutting edges of a drill bit gradually become blunt. A worn drill bit may require greater drilling pressure, generate excessive heat or produce holes with an inconsistent finish.

Sharpening helps restore the cutting edges when the condition of the drill bit allows it, avoiding the need to systematically replace tools that have simply become blunt.

This machine can be used for several applications:

• Resharpening HSS drill bits used for general metal drilling operations.
• Sharpening cobalt drill bits with a grinding wheel suitable for their composition.
• Restoring worn cutting edges on drill bits showing normal signs of wear.
• Sharpening larger-diameter drill bits up to 20 mm.
• Adjusting the drill point angle within the machine's specified adjustment range.
• Performing drill point thinning to improve the geometry of the drill point.
• Maintaining workshop drilling tools used in mechanical workshops and maintenance departments.

The machine can also be used to sharpen certain carbide drill bits, provided that a compatible diamond grinding wheel suitable for this material is installed.

Adjustable Drill Point Angle from 90° to 135° for Different Drilling Applications

One of the main advantages of the M4P MR20S drill bit sharpener is its adjustable sharpening angle from 90° to 135°.

This adjustment range allows different drill point geometries to be reproduced according to the type of drill bit, the material being drilled and the operation to be performed.

The drill point angle influences how the drill enters the material, the cutting forces generated and the behaviour of the tool during drilling.

A 118° point angle is commonly used on HSS twist drill bits intended for general metalworking applications. Other angles may be preferred depending on the drill bit geometry and the manufacturer's recommendations.

Thanks to its wide adjustment range, the MR20S allows the appropriate angle to be selected without being limited to a single sharpening configuration.

This versatility is particularly useful in workshops that use different types of drill bits for a variety of applications.

However, it is important to respect the original characteristics of the drill bit and avoid unnecessarily modifying its geometry when it has been designed for a specific application.

Drill Point Thinning Function to Improve Centring and Reduce Drilling Force

The M4P by Bernardo MR20S also stands out thanks to its integrated drill point thinning function.

On a conventional twist drill bit, the central web is the section located between the two flutes. At the drill point, it forms a chisel edge that does not cut the material in the same way as the main cutting lips.

This central area can generate considerable axial force, particularly when the drill bit has a relatively thick web.

Drill point thinning consists of locally modifying this geometry to reduce the width of the chisel edge.

When performed correctly, this additional sharpening operation offers several advantages:

• Improved centring: the drill point can enter the material more easily.
• Reduced axial force: less pressure may be required to start drilling.
• Better starting performance: the drill bit may be less likely to wander across the workpiece surface.
• Optimised point geometry: the cutting tool can regain characteristics better suited to its intended application.

This feature represents a valuable advantage over basic drill bit sharpeners that only allow the two main cutting lips to be sharpened.

It is particularly useful for larger-diameter drill bits, where reducing the axial force can make drilling operations easier and more comfortable.

ER20 and ER25 Collet Holding System for Accurate Sharpening

The MR20S twist drill bit sharpener uses an ER20 and ER25 collet clamping system to hold drill bits securely during the preparation and sharpening stages.

This system allows the drill bit to be positioned in a collet holder suited to its diameter.

The dedicated collet holder guidance system contributes to consistent sharpening and helps minimise differences in geometry between the two cutting lips.

The machine is supplied with 18 collets, divided into two sets.

11 ER20 collets:

• 3 mm
• 4 mm
• 5 mm
• 6 mm
• 7 mm
• 8 mm
• 9 mm
• 10 mm
• 11 mm
• 12 mm
• 13 mm

7 ER25 collets:

• 14 mm
• 15 mm
• 16 mm
• 17 mm
• 18 mm
• 19 mm
• 20 mm

A collet holder suitable for the machine's ER20 or ER25 clamping system is also included.

The ER20 and ER25 collets allow drill bits of different diameters to be secured, including certain intermediate sizes when these fall within the clamping range of the selected collet.

For small-diameter drill bits, it is important to check that the selected collet is compatible with the actual diameter of the drill bit shank.

Positioning and clamping must be carried out in accordance with the manufacturer's instructions to ensure accurate sharpening results.

CBN Grinding Wheel Included for Sharpening HSS Drill Bits

The M4P MR20S drill bit sharpener is supplied with a CBN grinding wheel.

CBN, or cubic boron nitride, is an abrasive particularly suitable for sharpening many high-speed steel tools, including HSS drill bits.

This abrasive technology offers good wear resistance and enables accurate sharpening of cutting edges when the correct operating conditions are observed.

The supplied CBN grinding wheel is therefore suitable for routine sharpening operations on compatible drill bits.

It is particularly useful for maintaining high-speed steel drill bits regularly used in mechanical and metalworking workshops.

Important: sharpening carbide drill bits requires a compatible diamond grinding wheel. The standard CBN wheel should not be considered a universal grinding wheel for every drill bit material.

The grinding wheel must always be selected according to the drill bit material and the manufacturer's recommendations.

120 W Motor and 4400 rpm Grinding Wheel Speed

The M4P by Bernardo MR20S drill bit sharpener is equipped with a 0.12 kW motor, equivalent to 120 W.

This motor drives the grinding wheel at a speed of 4400 revolutions per minute.

These characteristics are suitable for twist drill bit sharpening operations, which require controlled contact between the grinding wheel and the cutting edges.

The collet holder guidance system makes it easier to position the drill bit and contributes to consistent sharpening results.

The machine is designed to provide fast and straightforward sharpening operations, provided that the tools are correctly prepared and positioned.

Excessive pressure should be avoided during sharpening to preserve both the cutting edges and the grinding wheel.

A Compact Drill Bit Sharpening Machine for Mechanical Workshops

With dimensions of just 290 x 145 x 155 mm, the MR20S is a compact machine that can easily be installed on a workbench.

Its approximate weight of 8.2 kg makes it convenient to move or store when workshop space is limited.

It therefore provides a practical solution for users who want a dedicated drill bit sharpening machine without installing large equipment.

Its 230 V single-phase power supply allows it to be used in workshops equipped with a suitable electrical installation.

This sharpener is a useful addition to workshops equipped with pillar drills, drilling and milling machines or other metalworking equipment.

Thanks to its sharpening capacity of up to 20 mm, it is particularly suitable for users who work with a wide range of drill bit diameters.

Technical Specifications of the M4P by Bernardo MR20S Drill Bit Sharpener

Below are the technical specifications of the M4P MR20S twist drill bit sharpener:

• Brand: M4P by Bernardo
• Model: MR20S
• Manufacturer reference: 1016070
• EAN: 9009468081775
• Machine type: Twist drill bit sharpener
• Drill bit type: Two-flute twist drill bits
• Sharpening diameter: 2 to 20 mm
• Adjustable drill point angle: 90° to 135°
• Drill point thinning function: Yes
• Grinding wheel speed: 4400 rpm
• Motor power: 0.12 kW (120 W)
• Power supply: 230 V single-phase
• Length: 290 mm
• Width: 145 mm
• Height: 155 mm
• Approximate weight: 8.2 kg
• Grinding wheel supplied: CBN grinding wheel
• Clamping system: ER20 and ER25 collets
• Number of collets supplied: 18
• ER20 collets: 11 collets from 3 to 13 mm
• ER25 collets: 7 collets from 14 to 20 mm
• Collet holder: Included

Standard Equipment Supplied with the M4P MR20S Drill Bit Sharpener

The M4P by Bernardo MR20S twist drill bit sharpener is supplied with the following equipment:

• 1 CBN grinding wheel for sharpening compatible drill bits.
• 11 ER20 collets in nominal sizes 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and 13 mm.
• 7 ER25 collets in nominal sizes 14, 15, 16, 17, 18, 19 and 20 mm.
• 1 collet holder suitable for the machine's clamping system.

The machine also features an integrated drill point thinning device.

Important: the diamond grinding wheel required for sharpening carbide drill bits is not listed among the standard accessories supplied with the machine.

How to Use a Twist Drill Bit Sharpener Correctly

To achieve satisfactory results with the MR20S, it is important to prepare each drill bit correctly before sharpening.

The first step is to check the general condition of the drill bit. A tool that has simply become blunt can usually be resharpened, while a drill bit showing cracks, significant deformation or severe damage should be carefully inspected and replaced if necessary.

Next, select the ER20 or ER25 collet suited to the drill bit diameter and position the tool according to the procedure described in the machine's operating manual.

The drill point angle should be adjusted according to the required geometry and the characteristics of the tool.

After sharpening the main cutting lips, the drill point thinning device can be used when this operation is appropriate for the drill bit.

Several precautions help improve sharpening quality:

• Use a grinding wheel suitable for the drill bit material.
• Check that the drill bit is correctly secured in its collet.
• Respect the recommended drill point angle.
• Avoid applying excessive pressure during sharpening.
• Wear appropriate eye protection.
• Wait until the grinding wheel has completely stopped before carrying out any intervention.
• Disconnect the machine from the power supply before maintenance or grinding wheel replacement.

A visual inspection of both cutting lips after sharpening helps verify their consistency and identify any irregularities.

Why Choose the M4P MR20S Drill Bit Sharpener from Probois Machinoutils?

The M4P by Bernardo MR20S twist drill bit sharpener is an excellent solution for users who want to maintain their drilling tools and reduce the need to replace drill bits that have simply become blunt.

Its 2 to 20 mm sharpening capacity, adjustable 90° to 135° drill point angle and drill point thinning function provide useful features for maintaining twist drill bits.

The ER20 and ER25 collet holding system, 18 supplied collets and included CBN grinding wheel allow users to work with a wide range of drill bit diameters.

With its 120 W motor, 230 V power supply and compact dimensions, this machine can easily be accommodated in a mechanical or maintenance workshop.

At Probois Machinoutils, we offer a selection of metalworking machines and accessories, including drill bit sharpeners, pillar drills, drilling and milling machines, metal drill bits and machining accessories.

Choose the M4P by Bernardo MR20S drill bit sharpener to maintain your 2 to 20 mm twist drill bits and restore cutting edges suited to your drilling operations.