Cutting discs are also referred to as abrasive wheels or grinding
wheels. They are wheels manufactured using abrasive particles which are bound
together with different materials, like rubber or silicate, for example.
They are utilised throughout many industry types. And they are susceptible to breakage, so following the manufacturer’s safety guidelines and safety procedures is critical. This guide is designed to help give you a greater understanding of these popular pieces of equipment. Always read the manufacturer’s own instructions prior to use.
1. Markings
Markings are the right place to start. They are very important. Having
the information at your fingertips can save you valuable time and money not to
mention the peace of mind when it comes to the all-important health and safety
side of things.
Cutting discs are marked with the following information:
- Type
- Size
- Specification
- Maximum operating speed
- Restrictions for use
- Other, non-safety related information
Markings must conform to British Standards (BS EN 12413 and BS ISO 525) by law. So, to give
you a true understanding of what these labels mean, let’s look at them one by
one.
Type. This can be seen by way of an ISO
number. It indicates the disc’s shape.
Size. Disc measurement is denoted in
millimetres by diameter x thickness x hole size. So, you might see something
like 115mm x 1.0mm x 22.2mm.
Specification. The
specification is shown by way of numbers and letters, such as WA 60 K 7 V. This
signifies abrasive material type, grit size, grade, structure and bond type.
The following is a generic list of specifications:
The WA stands for the Abrasive materials, here are some other codes for abrasive materials:
- A: regular aluminium oxide
- WA: white aluminium oxide
- 19A: A and WA mix
- SD: synthetic diamond
- ASD: synthetic diamond, metal coating
- FA: semi-friable aluminium oxide
- PA: pink aluminium oxide
- SA (HA): single crystal aluminium oxide
- 23A: A and SA mix
- AZ: zirconium oxide
- C: black silicon carbide
- GC: green silicon carbide
- RC: C and GC mix
60 stands for the grit size which is separated like so:
(Coarse) 10,
12, 14 and so on, to 800, 100, 1200 (Fine)
K stands for the grade which range from
(Soft) A, B, C, and so on, to X, Y, Z
(Hard)
7 is the structure:
(Dense) 1, 2, 3, and so on, to 12,
13, 14 (Open)
V is the bond type are those codes go as follows: –
- V: vitrified
- B: resinoid
- R: rubber
- O: MgO
- E: epoxy
- M: metal
- EP: electroplated
2. Maximum operating speed
This is marked on every disc above 80mm in diameter
and is done in one of two ways:
- peripheral surface speed, noted in metres per
second (m/s); and - rotational speed, noted in revolutions per minute
(rpm).
For smaller wheels, the maximum speed is marked
separately on a notice that you need to keep by the wheel.
The following colours are used in stripes across
the middle of the disc:
- 125m/s Blue/Yellow
- 100m/s Green
- 80m/s Red
- 60m/s Yellow
- 50m/s Blue
Restrictions for use
These are marked on the disc using a code
indicating the following:
Meaning – Code
- Not permitted for hand-held and manually guided grinding – RE1
- Not permitted for hand-held cutting-off machines – RE2
- Not suitable for wet grinding – RE3
- Only permitted for totally enclosed working area – RE4
- Not permitted for face grinding – RE6
You’ll find that the code is sometimes accompanied with a corresponding graphic.
3. Other non-safety related markings
Other markings you’ll find on cutting discs are:
- the manufacturer’s name/trademark
- the test record number which confirms it meets the required safety standards
- the expiry date if the wheel is organically bonded (the shelf-life needs thought prior to purchase)
- a code number which confirms its source and details of manufacture
- a mounting arrow which highlights the heaviest point of the disc. When the disc is mounted, the arrow should be pointing downwards
4. Important Notes to consider prior to purchase
These tools must be treated with care at all times; whether in use, being handled or stored (in a dry place that isn’t subject to extreme temperatures is ideal), all operators must understand not just the markings, but also the hazards that using tools of this nature can bring. They must be inspected regularly; we recommend prior to each use, though the manufacturer’s instructions usurp this guide.
We suggest clearly marking the date of receipt from the supplier. That way, you can use the discs you’ve had the longest. If you ever have a disc that is over three years old, speak to the manufacturer to check whether it is still OK to use.
5. It is vital that the right disc is selected for each job. Every single time. So, it’s important to be specific about what it will be needed to do.
If you are new to cutting discs altogether, it may
help to know that generally speaking, soft wheels are better for use on hard
material and hard wheels on soft material.
Things like dust, noise and vibration should be
given consideration. And there is no better time to do it than prior to
purchasing a new one.
All operators should be given the appropriate training. And remember to refresh this regularly to be sure the information they have been given is up to date. We stock a wide and diverse range of cutting discs and are always happy to help should you need any more information. We sell accompanying equipment, such as grinding machines, guards and personal protective equipment.
We can help guide you through which products work with which so before you make your choice, why not take a look here at the ranges we have to offer.