1. Procedure for Operating Grinding Wheels (Fixed and Handheld) Revision 3 – 30 th March 2011 Toolbox Talk

2. Hazards and risks The main hazards associated with the use of grinding wheels are: Injury from ejected particles. Impact injuries from bursting wheels (usually caused by incorrect mounting of the wheel OR overspeeding of the wheel and/or machine). Injury through contact with the rotating wheel. Injury through trapping between the wheel and workrest. Injury from a work piece being thrown out of machine. Burns from contact with material being ground. Risk of fire from hot ejected particles/sparks Inhalation of dust. Hand arm vibration if used for long duration (note: it is expected that grinding wheels will only be used for very short duration work).

3. Authorised Persons Grinding wheels must not be operated or changed by persons not authorised to do so. All authorised persons must have attended a University approved abrasive wheels training course. Lists of those persons trained and authorised to operate grinding wheels and those authorised to change/dress grinding wheels are displayed in the workshops at Bedford Road and Rowett.

4. PPE to be worn when using grinding wheels Safety glasses/visor which are rated for use with grinding wheels (note: the list of approved PPE states which models are suitable for use when using grinding wheels). Disposable half mask respirator P3 Type (if appropriate for the task). Hearing protection (if appropriate for the task). Items not to be worn and other precautions Loose fitting clothing, long sleeves, jewellery, scarves or anything else that could become entangled in the wheel must not be worn. Long hair must be tied back. Gloves (optional) should only be worn if they are tight fitting drivers gloves NOT standard riggers gloves.  No eye protection

5. Requirements for fixed grinders Fixed grinders must have an independent emergency stop button. An exclusion zone should be permanently marked on the floor around the grinder. The grinder must be securely attached to the floor (if on a pedestal) or bench (if bench mounted).

6. Pre-use checks for fixed grinders Examine the floor area around the grinder to ensure that the exclusion zone marked on the floor is clear from any slip or trip hazards. Check that the grinder is securely attached to the floor (if pedestal mounted) or bench (if bench mounted). 

7. Pre-use checks for fixed grinders (continued) Tool rests should be good condition (no excessive wear), secure and adjusted so that they are as close as practicable to the wheel, the distance between the wheel and toolrest should not be more than 2mm. Guards should be securely attached to the body of the machine and be properly adjusted for the job in hand. Inspect the wheel mounting system on the machine (spindle, flanges and bearings) and the wheel for any signs of damage or uneven wear. The machine and wheel must be taken out of use if any defects are found, defects should be reported to one of the persons authorised to change wheels who will carry out the necessary adjustments or repairs. Remove any flammable material nearby. 

8. Requirements for hand held grinders Electrically operated grinders must be 110V. If the grinder is electrically operated it must be PAT tested every 3 months.

9. Pre-use checks for hand held grinders Check whether a Hot Works Permit to Work will be required (Note: this will generally be the case for all internal works or works close to buildings). Remove any flammable material adjacent to the job in hand. Temporary barriers may be required if the work is to be carried out in a busy area. Ensure adequate ventilation if the grinder is petrol driven. Ensure body of grinder is not cracked or damaged. If the grinder is electrically operated ensure cable and plug is not damaged. If the grinder is electrically operated, check the label of the grinder to ensure that is has been PAT tested within the last 3 months. Do not use the grinder if it has not been tested within the last 3 months. Ensure that the guards are in place. Check that all controls work properly. The item being worked on should be securely positioned so that it will not move whilst the work is being carried out.

10. Use of equipment (general) Do not make any adjustments to the wheel, toolrest or guards whilst the machine is switched on. Side grinding must never be carried out on any of the fixed grinding wheels. 

11. Use of equipment (general) Angle grinding may only be carried out using portable handheld grinders with depressed wheels designed specifically for that purpose. The optimum angle for carrying out angle grinding is 30° - never grind at 90° to the wheel. Angle grinding with hand held grinder at 90° to object – bad practice Angle grinding with hand held grinder with depressed wheel at 30° to object 

12. Use of equipment (general) Do not use excessive force. Workpieces should not be pressed hard against the grinding wheel (there may be a tendency to do this as the wheel starts to loose efficiency as it is worn down). Moving wheels must not be stopped by applying pressure to any part of the wheel. Wheels should only be used for grinding the materials they were designed for. Contact with other materials such as wood will damage the wheel. Never weld anything that may have held flammable liquids or gases. (see the following article on a fatal accident which occurred locally) http://www.pressandjournal.co.uk/Article.aspx/1792016?UserKey 

13. Changing wheels and dressing wheels Storage of wheels Wheels should be ordered in as required rather than stored if possible. Where wheels are stored they should be kept on a rack specifically designed for that purpose. New wheels Wheels should be carefully unpacked. They should never be rolled, bumped, thrown or dropped. Never use a wirebrush on a wheel. 

14. New wheels (continued) New wheels should be examined for any possible damage. The ‘ring’ test should be carried out on the wheel to check soundness. Use a non-metallic object - if the wheel sounds dead (a dull thud rather than a ring) it should not be used. Grinding wheels have a limited shelf life, they should not be used if they are more than 3 years old.

15. New wheels (continued) When selecting the wheel for the machine the authorised person must ensure that the wheel is: (i)Appropriate for the machine. The speed of the machine should not exceed the maximum permissible speed of the wheel. The wheel must not be too large for the machine, this is particularly important when using portable grinders. (ii) Appropriate for the task. The power supply to machines must always be isolated and locked off before removing an old wheel and installing a new one.

16. New wheels (continued) Flanges for mounting wheels should generally be at least one third of the diameter of the wheel and of equal diameter of both sides of the wheel. Blotters should be used between the wheels and their flanges. Do not tighten the mounting nuts for the wheel excessively. With the power still isolated and locked off, rotate the wheel by hand to ensure it is clear all the way round. For fixed grinders the gap between the toolrest should be no more than 2mm. New wheels on fixed grinders should be run free at normal operating speed for about a minute. All persons should stand clear during the trial run. The guards must be in place when this is done.

17. Trueing and dressing wheels When dressing wheels proper dressing tools must be used. Disposable half mask respirator P3 Type to be worn when carrying out this task. Maintenance Weekly checks will be carried out by authorised staff appointed by the Senior Engineers at Bedford Road and Rowett. The checks must be recorded and these will be kept by the Senior Engineers at Bedford Road and Rowett. Further Guidance For further information on the safe use of grinding wheels refer to the HSE publication HS(G)17 - Safety in the use of Abrasive Wheels, 3 rd Edition 2000.