Forty abrasive-wheels terms, in plain English, ordered alphabetically, with the practical meaning every Irish operator and supervisor needs to recognise on the shop floor.
A
Abrasive grain. The cutting particle in the wheel. Aluminium oxide for general purpose, silicon carbide for hard or non-ferrous metals, CBN and diamond for hardened tools.
Aluminium oxide. The most common synthetic abrasive grain in Irish workshop wheels.
Arbor. The shaft on which the wheel is mounted. The bore of the wheel must match the arbor diameter.
B
Bench grinder. A fixed machine, typically with two wheels mounted on a single shaft, used for general-purpose grinding and tool sharpening.
Blotter. A paper or pressed-card disc that sits between the flange and the wheel face to distribute clamping force evenly. Always use a fresh one on each side.
Bond. The material that holds the abrasive grains together in the wheel - vitrified, resinoid, rubber, shellac.
Bore. The hole in the centre of the wheel that fits the arbor.
Burst. Catastrophic failure of a wheel under rotation. Almost always preventable through training, inspection and correct selection.
C
CBN (cubic boron nitride). Synthetic super-abrasive used on hardened steels.
Cup wheel. A wheel shaped like a hollow cylinder, used for grinding flat surfaces from the rim.
Cut-off saw. Petrol or electric machine using an abrasive disc to make rapid cuts in metal, masonry or concrete.
D
Diamond wheel. A wheel with diamond grains bonded to the periphery, for cutting and grinding hard materials including stone, concrete and carbide.
Dressing. The process of restoring a glazed wheel to a sharp cutting condition using a star, diamond or stick dresser.
F
Flange. The metal disc that clamps the wheel against the spindle, with a relieved (recessed) inner face.
Flap disc. A wheel made from overlapping flaps of coated abrasive cloth, used for finishing and weld dressing.
FFP3. European standard for filtering facepiece respirators with 99 percent efficiency against fine particulate including silica.
G
Grit. The size of the abrasive grains. Lower numbers = coarser grit; higher numbers = finer grit.
Grade. The hardness rating of the bond. Soft grades release worn grains quickly; hard grades hold them longer.
Guard. The protective cover that surrounds part of the wheel and contains fragments in the event of a burst.
H
HAVS. Hand-arm vibration syndrome - the long-term injury from prolonged use of vibrating tools.
HSA. Health and Safety Authority - the Irish workplace safety regulator.
L
LEV. Local exhaust ventilation - a hood or extractor that captures dust at the cutting point.
M
Maximum operating speed. The fastest surface speed at which the wheel can safely run, in metres per second, printed on the wheel marking.
Mounted point. A small abrasive wheel on a steel shank, used in die grinders for detailed work.
P
Pedestal grinder. A floor-standing version of the bench grinder.
PPE. Personal protective equipment - safety glasses, hearing protection, respirator, gloves, boots.
PUWER. The UK's Provision and Use of Work Equipment Regulations 1998 - the equivalent of Irish SI 36/2016.
Q
QQI. Quality and Qualifications Ireland - the national qualifications authority.
R
RCD. Residual current device - the electrical safety device that disconnects power on detecting an earth leakage. Mandatory for portable grinders on temporary supplies.
Refresher course. The renewal training taken before the certificate's three-year expiry.
Resin-bonded wheel. A wheel bonded with phenolic resin. Has an expiry date.
Ring test. The pre-mount test for vitrified wheels that listens for a clear ring (pass) or a dull thud (fail).
RoSPA. The Royal Society for the Prevention of Accidents - the most-recognised independent safety quality mark in the UK and Ireland.
RPM. Revolutions per minute - the rotational speed of the spindle.
S
SI 36/2016. The Irish Statutory Instrument that updates the General Application Regulations to specify duties for work equipment, including abrasive wheels.
Silica. The respirable crystalline mineral found in stone, brick, concrete and engineered stone. The leading cause of occupational lung disease in Irish workshops.
Spindle lock. The button on a grinder that holds the spindle stationary while the retaining nut is tightened. Release before powering up.
Surface speed. The linear speed of a point on the wheel's periphery, in metres per second. Calculated from spindle RPM and wheel diameter.
T
Tool rest. The metal bracket on a bench grinder that supports the workpiece. Must be set within 3 mm of the wheel.
V
Vitrified bond. A glassy ceramic bond fired at high temperature. Strong, brittle, common in bench-grinder wheels. Subject to the ring test.
W
Written authorisation. The one-page document signed by the employer authorising an operator to mount and use specified wheels and machines.
Train every operator to fluency
The vocabulary above is built into the Abrasive Wheels Course. By the time the certificate is issued, every term here is part of the operator's working language.
