What are petal circles?
Flap discs are abrasive tools with flaps of sanding paper applied to their base. They are intended exclusively for grinding on angle grinders.
Flap wheels combine the performance of a grinding wheel with the clean finish of sanding paper, making them one of the most popular abrasive tools.
Types of petal circles
There are two main types of flap discs for grinders:
- Flat— for working at an angle to the surface
- Conical (with inclination) - for working at a larger angle, more convenient for most operations
Protective cover for flap discs
Flap discs are used only for grinding, so a suitable guard is required:
- For 180 mm and 230 mm wheels - casing with closed protection on top
- For wheels smaller than 180 mm - standard grinding guard
EN 13743 marking - what does it mean?
Flap discs are marked according to EN 13743 (not EN 12413, like Bakelite). The marking contains 7 elements:
| № | Marking element |
|---|---|
| 1 | Declaration of Conformity EN 13743 |
| 2 | Maximum speed (rpm) |
| 3 | Maximum operating speed (m/s) |
| 4 | Manufacturer / brand |
| 5 | PPE icons (optional) |
| 6 | Dimensions (mm) |
| 7 | Specification (optional) |
10 Safety Rules: WHAT TO DO and WHAT NOT TO DO
1. Check the EN 13743 marking
✅ CORRECT: Make sure the wheel is marked EN 13743.
❌ WRONG: Do not use a wheel without the EN 13743 marking.
2. Read the instructions
✅ CORRECT: Always read the safety instructions.
❌ WRONG: Don't throw away the instructions without reading them.
3. Inspect the wheel before use
✅ CORRECT: Inspect the wheel for cracks, peeling petals, and unusual stains.
❌ WRONG: Never use a damaged wheel.
4. Check the speed
✅ CORRECT: The speed of the car must not exceed the maximum speed of the lap.
❌ WRONG: Do not use the wheel if its speed is lower than the speed of the car.
5. Correct installation of flanges
✅ CORRECT: Align the flanges correctly when installing.
❌ WRONG: Misaligned flanges cause runout and uneven wear.
6. Protective cover is mandatory
✅ CORRECT: Always work with the protective cover in place.
❌ WRONG: Never remove the casing.
7. Secure the workpiece
✅ CORRECT: The workpiece must be securely fixed.
❌ WRONG: Never sand an unstable workpiece.
8. Personal protective equipment
✅ CORRECT: Use safety glasses, gloves, headphones, and a respirator.
❌ WRONG: Never sand without protective equipment.
9. For grinding only
✅ CORRECT: Flap wheels are intended exclusively for grinding.
❌ WRONG: Never use flap discs for cutting.
10. Work without excessive pressure
✅ RIGHT: Work in even movements along the surface without excessive force.
❌ WRONG: Never apply excessive pressure to the wheel - this reduces its service life and worsens the quality of the finish.
Advantages of petal circles
- Less vibration compared to Bakelite polishing wheels
- Lower noise level during operation
- Better material removal control
- Cleaner surface— less finishing required
- Safer - not prone to sudden breakage like Bakelite wheels
Frequently asked questions
Can I cut with a petal wheel?
No. Flap wheels are intended for grinding only. Attempting to cut may result in wheel breakage and injury to the operator.
What is the difference between flat and conical petal circles?
Flat - for working at a small angle to the surface. Conical (with a slope) - for working at a larger angle, more convenient for most grinding operations. The choice depends on the working angle and convenience.
Which standard is used for flap discs - EN 12413 or EN 13743?
Flap discs are marked according to EN 13743 (flexible abrasives). EN 12413 only applies to Bakelite discs (cutting and grinding). Do not confuse these standards.
Why are petal wheels safer than Bakelite wheels?
Flap wheels are not prone to sudden breakage (rupture) like Bakelite wheels. They wear out gradually—the flaps wear away, making the process more predictable and safer. They also create less vibration and noise.
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