Do not use with hand-held grinding machine
Use of the marked abrasive product with a hand-held grinding machine is prohibited.
Understanding this sign
Red circular signs with a diagonal bar identify an action that must not be taken in the marked area.
Check what object or action the symbol prohibits. A prohibition sign does not identify all the hazards in an area.
A Machine-Class Restriction, Not a Quality Grade
ISO 7010 P034 marks abrasive wheels that must not be mounted on hand-held grinding machines. The distinction it draws is between fixed machines — bench, pedestal, and stationary grinders that hold the wheel in a rigid spindle with controlled feed — and portable angle or straight grinders that a person aims by hand. A wheel made for the first environment can be lethal in the second, even if its diameter and bore happen to fit the portable tool.
Hand-held use subjects a wheel to loads a fixed machine never applies: twisting and bending as the operator angles the tool, shock when the wheel snags or is dropped onto the work, and side pressure that varies stroke by stroke. Wheels intended for portable grinders are built for this, typically with internal fiberglass-mesh reinforcement that holds fragments together under flexing. Wheels for stationary machines generally lack that reinforcement, and under hand-held loading they can crack and burst.
Speed Is the Second Half of the Problem
Every bonded wheel carries a maximum operating speed, and the mismatch between wheel classes is often rotational as much as structural. Portable grinders commonly spin small wheels at very high rpm, while large stationary wheels are rated for much lower spindle speeds. Mounting a wheel on any machine whose no-load speed exceeds the wheel's marked maximum is prohibited outright by ANSI B7.1 and by EN 12413 alike, and P034 frequently flags products that would fail that check on a typical portable tool.
Centrifugal stress grows with the square of speed, so even a modest overspeed pushes a wheel far beyond its design margin. This is why competent-person mounting procedures require comparing the wheel's marked speed with the machine's spindle speed before every mount — the P034 pictogram on the label is the first, fastest version of that comparison, ruling out an entire machine class at a glance.
Reading P034 Alongside P032 and P033
ISO 7010 registers three companion prohibitions for bonded abrasives, and each answers a distinct pre-use question. P034 asks: is this wheel allowed on the machine in my hands? P032 asks: may I grind with its face or only its edge? P033 asks: may it run wet? A wheel's label can carry any combination, and mounting training treats checking the trio as a single inspection step along with the speed marking and a visual and ring check for cracks.
The practical risk P034 targets is improvisation in the field: a portable grinder, a job to finish, and a bin of wheels bought for the pedestal machine in the shop. Because the bore may adapt and the wheel may physically mount, nothing but the label and the operator's training stands between that improvisation and a wheel burst inches from the hands and face. Stocking machine-matched wheels at the point of use removes the temptation.
Where you will see P034
It appears on the labels of bonded abrasive wheels intended for stationary machines, ruling out an entire machine class at a glance during pre-mount checks alongside P032, P033, and the marked maximum speed. Workshops running both pedestal grinders and portable angle grinders rely on it to stop field improvisation — a bore that happens to fit does not make a bench wheel safe on a hand-held tool spinning at far higher rpm.
Common questions about P034
What does the P034 pictogram on an abrasive wheel mean?
That the wheel must not be used on a hand-held (portable) grinding machine. It is designed for fixed machines such as bench or pedestal grinders, and lacks the reinforcement and often the speed rating needed to survive the flexing, snagging, and high rpm of hand-held use. Mounting it on an angle grinder risks the wheel bursting.
If a wheel fits my angle grinder, why can't I use it?
Physical fit proves nothing about structural suitability. Wheels for stationary machines typically lack the fiberglass reinforcement that holds hand-held wheels together under bending and shock, and their maximum speed may be below the grinder's spindle speed. Centrifugal stress rises with the square of rpm, so an overspeeded, unreinforced wheel can shatter close to your hands and face.
How do I check whether a disc is approved for portable grinders?
Read the label: it states the maximum operating speed and carries restriction pictograms. If the crossed-out hand-held-grinder symbol (P034) appears, the wheel is for fixed machines only. Also confirm the wheel's marked maximum speed meets or exceeds the grinder's no-load spindle speed — that check is required before every mounting.
What is the difference between P032, P033, and P034?
They are the three standard misuse prohibitions for bonded abrasive wheels. P032 forbids face (side) grinding with wheels made for edge use. P033 forbids wet grinding with wheels whose bond is not rated for liquid. P034 forbids mounting the wheel on hand-held machines. A single wheel can carry one, two, or all three.
Reference details
| Symbol code | P034 |
|---|---|
| Sign family | ISO Prohibition Signs |
| Standard reference | ISO 7010:2019 / ISO 3864-1 ISO Online Browsing Platform: P034 |
| Screen color reference | #FF0000. Screen colors are not a production color specification. |
| Download formats | SVG reference artwork; a 1024 × 1024 pixel PNG conversion on a white canvas. |
| Record date | · How to interpret our dates |
| Page updated |
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- Original: ISO Vector: Uploader
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