Views: 0 Author: Site Editor Publish Time: 2025-06-16 Origin: Site
Do your parts look scratched or uneven after grinding? The wrong convolute wheel could be the reason. Choosing the correct one affects finish, speed, and cost.
In this post, you’ll learn how to read wheel codes, select the right hardness, grit, and grain.
We’ll also cover ideal speeds, maintenance tips, and common questions.
A convolute wheel is layers of non-woven fiber coiled tight around a solid core.
Fibers, resin, and abrasive grains fuse during curing; the roll forms one resilient body.
Because the layers spiral in one direction, the wheel must spin that same way.
That single rotation path keeps every grain cutting at the identical contact angle.
● Consistent cut – uniform density means even pressure across the face.
● Cooler running – open web lets air move, heat falls fast.
● Minimal gouging – fibers cushion the impact, protect part geometry.
● Long life – self-sharpening action reveals fresh grain as fibers wear.
● Deburring laser-cut or machined edges.
● Blending weld seams until lines fade.
● Polishing stainless to a brushed satin.
● Removing rust, mill scale, or light oxidation on steel plate.
Feature / Task | Convolute | Unitized | Flap Disc | Bonded Wheel |
Build style | Wrapped web | Layer stack | Cloth flaps | Pressed grain |
Spin direction | One-way | Two-way | Any | Any |
Flexibility on curves | Medium | High | Medium | Low |
Heat generation | Low | Low | Medium | High |
Best for | Blend, finish | Edge precision | Fast stock | Heavy grind |
Typical speed range (SFPM) | 500-8000 | 300-6000 | 3000-9000 | 4000-9000 |
Convolute wheels sit between very soft flap discs and rock-hard bonded stones, so they bridge tasks that need finesse plus durability.
A convolute wheel tag reads like “7 S F”.
Three symbols tell us everything we need.
Example | Density (1st) | Grain (2nd) | Grade (3rd) |
7SF | 7 Soft | S Silicon Carbide | F Fine |
9AM | 9 Hard | A Aluminum Oxide | M Medium |
9AF | 9 Hard | A Aluminum Oxide | F Fine |
● 7 = Soft | great on decorative pieces, curves.
● 8 = Medium | our all-round starter choice.
● 9 = Hard | bites heavy burrs fast.
● XL open web, adds flexibility.
● XL2 extra grain, extra resin, survives tough jobs.
● S = Silicon Carbide → leaves a bright, shiny face.
● A = Aluminum Oxide → gives a muted satin.
● Fine (F) when finish rules, dust stays low.
● Medium (M) when speed wins, surface can wait.
Pick density for pressure, grain for shine, grit for speed.
● Soft 7 Curves, thin walls; dust signals wheel too soft for big burrs.
● Medium 8 Safe first pick; climbs up or down once you test.
● Hard 9 Heavy burrs, flat stock; watch for flat-spotting on edges.
● XL / XL2 Open web vs extra grain; choose XL2 when we need extra bite.
Burr Height | Best Density | Reason |
<0.1 mm | 7 | Wheel conforms, protects finish |
0.1–0.3 mm | 8 | Balanced cut and control |
>0.3 mm | 9 or XL2 | High pressure removes metal fast |
Grain | Code | Finish Look | Favorite Metals |
Silicon Carbide | S | Bright, reflective | Stainless, titanium, composites |
Aluminum Oxide | A | Dull satin glow | Mild steel, alloys, brass |
Silicon carbide chips sharp, stays cool.
Aluminum oxide lasts longer on tough ferrous parts.
● Fine (F) Decorative trims, last polishing pass, low removal.
● Medium (M) Functional surfaces, weld blending, faster stock removal.
Think of grit as camera focus.
Fine sharpens detail; medium erases material quickly.
Task | Best Speed Range | Why It Works |
Decorative finishing | 500 – 3,000 | Soft touch, uniform grain |
Composites / soft materials | 1,200 – 2,700 | Prevents smearing or melt |
Deburring hard burrs | 5,000 – 6,500 | High energy tears edges clean |
Blending / polishing | 6,000 – 8,000 | Produces quick, tight satin |
Need a target RPM?
Use RPM = (SFPM × 12) ÷ (π × wheel diameter inches).
● Water keeps metal cool; simple, cheap.
● Water-soluble oils boost life, cut faster.
● Tallow, grease give slickest finish, thicker film.
● Apply enough flow so slurry stays wet, not pasty.
1. Follow the arrow. Convolute wheels run one way only.
2. Respect the label RPM. Never exceed max speed stamped on hub.
3. Measure diameter often. A smaller wheel lowers SFPM; raise RPM within limits.
4. Guard and dress. Keep guards closed, dress wheels round before vibration starts.
● Diamond tool keeps hard wheels round; light passes stop overheating.
● Coarse abrasive sheet + steel block press it steady, let both surfaces bite.
● Custom metal rakes thin-edged, right-angle teeth slice soft wheels fast.
Tip: True wheels six inches or larger before vibration shows.
1. Reduce grinder speed by half, touch a coarse abrasive stick.
2. Move side to side, sparks tell us fresh grain appears.
3. Flush slurry, restart at normal speed.
Symptom | Cause | Remedy |
Excessive dust plume | Wheel too soft | Step up from 7 to 8 density |
Polished glaze, no cut | Loaded surface | Dress wheel; add coolant flow |
Chatter, bouncing | Out-of-round hub | Re-true using diamond tool |
Flat spots on work | Wheel too hard | Switch to 8SF or lower pressure |
● Start at 8 SF density; soft enough to hug curves.
● LDH wheels excel on aluminum, copper, plastics.
● Run 500–3 000 SFPM; slow speed keeps tool marks invisible.
Goal | Wheel | Speed | Note |
Satin on stainless panel | 8 SF | 2 000 SFPM | Light coolant spray |
Brushed copper trim | LDH | 1 200 SFPM | No lube, brighter tone |
● Pick 9 SF when burrs stand tall on thick steel.
● Need even more bite? Go XL2; extra grain rips metal fast.
● Stay in the 5 000–6 500 SFPM window for best edge removal.
Part | Wheel | Speed | Pressure |
Laser-cut carbon steel | 9 SF | 6 000 SFPM | Medium |
Forged bracket flash | XL2 | 5 500 SFPM | Firm |
● LDH vs LDP: LDH loves soft alloys; LDP tackles hard steels.
● For razor-sharp aerospace details, switch to EXU unitized wheels.
● Trim RPM 10 % below max when profiles get tight.
Challenge | Best Pick | Why |
Thin aluminum fins | LDH 7 F | Flex prevents breakage |
Cast iron manifold | LDP 9 M | Denser cut, no glazing |
Turbine vane edge | EXU 8 F | Layers cut clean, hold shape |
Q1: Can one wheel handle multiple materials?
A: Yes, but performance varies. Choose grain and grit based on material type for best results.
Q2: How do I know a convolute wheel is worn out?
A: If cutting slows, dust increases, or the wheel loses shape, it's time to replace or dress it.
Q3: What if I exceed the recommended surface speed?
A: Over-speeding can cause heat damage, reduce lifespan, or lead to safety risks like wheel failure.
Q4: Convolute wheels vs flap discs—when to switch?
A: Use convolute for precision finishing; flap discs suit aggressive material removal and faster jobs.
Q5: Do coolants affect the wheel’s cutting action?
A: Yes, coolants reduce heat, extend life, and improve surface finish by lowering roughness.
Choosing the correct convolute wheel depends on three key factors—hardness, grain type, and grit level. Each affects surface quality, speed, and part safety. Test different densities and abrasives to find what works best for your application. Start with medium settings, then adjust as needed for burr size, material type, and finish goals.
Ready to find the perfect convolute wheel for your finishing task? Download our free quick-reference chart to compare specifications like density, grain type, and grit—designed to simplify your selection process. Whether you're in aerospace, medical, automotive, or electronics, Pengyu provides precision tools engineered for your industry's demands.
At Tianjin Pengyu New Materials Co., Ltd., we go beyond supplying abrasive products—we deliver custom-engineered solutions that drive efficiency, reduce costs, and elevate performance. Contact our experienced sales and technical team for personalized support, expert recommendations, or a free quote. Let us help you achieve excellence in every application with the right abrasive wheel.
