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SAFETY RECOMMENDATIONS: 
DEPRESSED CENTRE
REINFORCED BONDED WHEEL
FOR GRINDING
WITH AN ANGLE GRINDER

a photo of man grinding a metalic tube with a depressed centre reinforced bonded wheel on angle grinder

a picture of an angle grinder next to a drawing with hands holding an angle grinder a depressed centre reinforced bonded wheel of maximum 230 millimeters diameter

  
Terminology: Reinforced resinoid wheels may also be named as depressed centre grinding discs, depressed centre flex discs, coolie hats discs, rondello wheels…
Reinforced resinoid wheels improperly used can be very dangerous: wheels run at 80 m/s on angle grinders and can eject parts at a speed of 288 km/h (180 mph) in case of breakage. FEPA has designed this page to provide the essential safety recommendations for use of reinforced resinoid wheels on angle grinders (not petrol saws), with maximum diameter of 230mm.

Abrasive products

 
These recommendations focus on reinforced resinoid wheels for grinding with angle grinders. They can be either depressed centre wheels, coolie hat wheels or semi-flexible (rondello):

a type 27 depressed centre grinding wheel
Depressed centre grinding wheel
(can be marked “type 27”)

a type 28 despressed centre grinding wheel
Depressed centre grinding wheel
also called “coolie hat wheels”
(can be marked “type 28”)

a type 29 depressed centre grinding wheel
Depressed centre grinding wheel
also called “rondello” 
(can be marked “type 29”)

Safety recommendations for the use of depressed centre reinforced bonded wheels for angle grinders

FEPA general safety principles

cover page of the safety recommendations leaflet for the use of abrasives products

Dos & Don’ts for these products

cover page of the FEPA safety leaflet about the use of cutting and grinding wheels for angle grinders

What is a safe product? What should I look for?


FEPA recommends that only products conforming to EN 12413 and marked as such should be used.

Reinforced resinoid wheels not bearing EN 12413 may not conform the highest safety standards.

Before selecting the wheels, ensure that the expiry date has not been exceeded. 

All wheels should be examined carefully for damage or defects before fitting on the machine.

 

 

How should I handle and store the wheels?


All abrasives wheels are fragile. They should be handled with care.

Wheel should be stored on a flat, rigid surface, avoiding damp and frost or wide variation in temperature.

Use the oldest wheels (on “first in, first out” basis).
 

 

 

 

 

 

 

 

 

 

 

 

How should I fit the wheel on the machine?

 
■ 
Follow carefully the instructions given in the machine handbook. 

Never fit a wheel which is loose or too tight on the flange. 

Align the outer flange correctly as shown in the FEPA Safety leaflet for cutting and grinding wheels for angle grinders (see above)

Tighten only with the tool supplied with the machine.

Ensure the wheel is properly gripped to prevent slippage, but do not tighten with excessive force. Never use a hammer. 

Keep flanges and screw threads clean and free of burrs and rust.

Replace distorted or damaged flanges before fitting the wheel.

Run all wheels after fitting for at least 30 seconds at operating speed keeping behind the guard in case the wheel breaks.

Refer to the FEPA recommended mounting check list.

How should I protect myself?

 
FEPA recommends the use of following personal protective equipment (often written PPE) : 

Eye protection 
■ Ear protection (ear sets)
■ Hand protection (gloves)
■ Lung protection (dust mask, also called respirator)

■ Never remove the protective machine guard and make sure it is properly adjusted to deflect debris away from you.

■ Ensure that no other person is at risk, especially near the machine while working.

 

 

 

 

 

 

 


How should I handle the wheel after use?


Before storing the machine or transporting it to another location, always remove the wheel and store it as recommended. 

Always carefully examine the wheel for damage or defects, and destroy and discard if damaged. 

Do not fit worn out wheels on a smaller machine. Destroy them.

If the wheel does not bear a legible expiry date, or has exceeded this date, dispose it as recommended below.

When disposing of worn out or defective wheels, it is recommended to damage them to prevent someone from removing them from waste and re-using them.

 

 

How can I get proper training?

 
It is a legal requirement for all employees involved in the use of abrasives wheels to be properly trained and also re-trained on a regular basis. They should consult their employer if they have not received this training.

■ The wheel manufacturer or supplier can advise you on suitable accredited training providers. 

■ As a private consumer, you should read carefully the safety information found in: 

 The grinding machine handbook
 The FEPA general safety principles leaflet (see above)
 The FEPA safety leaflet for cutting and grinding wheels for angle grinders (see above in Dos and Don'ts)

illustration of grinding with a depressed centre bonded wheel on an angle grinder


This website is intended to give information on safe use of abrasives in compliance with European standards, and not to give advice on product selection.
You should read the information given on the product or its packaging to determine suitability. For any specific question, contact the retailor who supplied you the product.