GTX Academy: TCT forked discs – ATB, FWF, TCG
2026-01-28
GTX Academy: Diamond discs – full/segment/turbo
2026-01-30A good disc for an angle grinder is not only the right diameter and a proven brand. The type of abrasive (A/C), type of disc (T41/T42/T27), grain gradation or bond hardness also determine the quality of cutting and grinding comfort. Below you will find a practical guide to help you select a disc so that you can work faster, cleaner and without overheating the machine - whether you intend to cut a steel profile or have plans to grind the edge of a slab.
Let's start with the material - choose the right abrasive (A/C)
- A: Electrocorundum: is the best choice for metals; structural steel, stainless steel and cast iron. It provides stable, predictable cutting and effective grinding.
- C: silicon carbide: use for stone, concrete, clinker and hard minerals. The grain in silicon carbide discs is noticeably sharper and more easily "bites" into the material. Great for brittle materials that do not particularly conduct heat well.
Then the task - choose the type of shield
- T41 - flat cutting disc
For cutting rods, profiles, sheet metal. Does not work sideways - with this type of disc we cut with the edge in a straight line. - T42 - cutting disc with flange
Also for cutting, but with more clearance between disc and grinder guard. More convenient when working close to the ground/wall. - T27 - flanged grinding wheel
For face/side grinding, overgrinding or chamfering. This is not a cutting disc.
How to choose the gradation (grain) of the alumina disc?
- Bardzo grube (P16–P24) -do szybkiego usuwania dużej ilości materiału, szlifowania spoin i obróbki zgrubnej stali konstrukcyjnej.
- Coarse (P30-P40) - for pretreatment, rust removal and preparation for further grinding.
- Medium (P50-P80) - for smoothing after roughing, preparation for painting and sanding of steel and wooden parts.
- Fine (P100-P120) - for finishing, varnish preparation and precision machining.
- Very fine (P150+) - less often used in classic discs for angle grinders, more often in discs or sandpaper.
How to choose the hardness of the binder?
- Soft (N-P) - for harder metals. The bond wears off faster, exposing fresh grains. The blade "self-sharpens" and heats up less during operation.
- Medium (Q-S) - the golden mean between performance and service life; among other things, a good choice for structural steels.
- Hard (T-V) - for softer, "fuzzier" materials (e.g., aluminum, copper, mild steel). The bond wears out more slowly, and the disc lasts longer.
Worth remembering: general rule - the further in the alphabet, the harder the dial. Hard material → choose a soft disc; soft material → choose a harder disc.
Example: metal cutting discs 125 x 1 x 22.2 mm, 41 A60-T-BF, 10 pieces film 55-578 NEO TOOLS:
- 41 - flat type,
- A - type of abrasive: electrocorundum,
- 60 - gradation: medium,
- T - hardness: hard,
- BF - type of binder: resin reinforced.
Quick picks
- Cutting structural steel (profiles/bars):
A (electrocorundum) + T41/T42 + 30-46 (medium) + Q-S (medium). - Grinding of welds/trim in steel:
A + T27 + 24-40 (coarse) + Q-S. - Cutting/machining stone, clinker, concrete:
C (SiC) + T41/T42 (cutting) + 24-36 + T-V (often better harder).
Operating parameters and technology
- Guiding angle: guide T41/T42 discs straight, with an edge; T27 works best at an angle (about 10-30°) or with a frontal setting - depending on the task.
- Pressure: light/medium; the disc is supposed to wear down, not slow down rotation.
- RPM: do not exceed the maximum speed from the device's specifications; typically, lower speeds give better control and generate lower temperatures.
- Cooling/breaks: for more complex designs, take short breaks to dissipate heat and clean up the gash/grease.
Health and safety and installation issues
- Grinder guard - necessarily installed and in good condition. Also remember safety glasses, mask, gloves.
- Flanges/flanges - clean and straight; disc bore compatible with the spindle (e.g., 22.2 / 25.4 mm).
- Do not use discs after the expiration date (quarter/year mark on the ring).
- Use cutting discs (T41/T42) for cutting; do T27 for grinding - do not swap the purpose of the disc.
3 most common mistakes → quick solutions
- Overheating, "blue" discoloration → RPM/pressure is probably too high. Drop the RPM, reduce the contact time with the material, and use a softer hardness (N-P) disc for hard steel.
- It cuts slowly or smears edges → selected too fine a gradation or too hard a disc for the type of material. Go down a mesh in grit (e.g., 60 → 36) or choose a softer hardness (S → P) accessory.
- Disc cracks → cutting sideways with T41/T42 discs, clamped cut or exceeded RPM can cause disc damage. Cut edge straight, control RPM, use T27 for grinding.
Where to buy
At GTX Academy, we rely on proven discs and work with accessories from NEO TOOLS and GRAPHITE brands. Go to fixero.com to choose the right alumina disc for the type of your job.
FAQ - the most common questions
1T41 or T42 to cut the profile near the floor itself?
T42 - thanks to the recessed flange, it will provide more clearance between the disc and the shield.
2What gradation to choose "to start with" for steel?
For cutting: 30-46; for rough grinding: 24-40; and for finishing: 60-80.
3Does the hardness of the disc matter with Inox steel?
Yes. Inox is "harder" to work with - so a softer bond (N-P), which sharpens itself and heats up less, works more often.
