For 6 years at Purple Café, I sharpened 8-12 professional knives weekly using the Norton IM200 Tri-Stone. In a 200+ cover restaurant where dull knives meant service delays, this three-stage system kept every blade razor-sharp through demanding dinner services. This isn't complicated—follow this exact technique and you'll achieve professional-quality results at home.
💡 Using the right sharpening system matters. The Norton IM200 Tri-Stone survived 6 years of professional restaurant use and delivers exceptional results. Read my complete review →
⚠️ Safety Note: Sharp knives are safer than dull knives, but the sharpening process itself requires care. Work on stable surface, keep fingers behind the blade edge, and maintain focus throughout the process.
The Norton IM200 features three progressively finer stones mounted in one base:
Purpose: Repair damaged edges, remove chips, establish bevel
When to use: Very dull knives, damaged edges, establishing new angle
Passes needed: 5-10 per side
Purpose: Refine edge, remove coarse scratches, develop working sharpness
When to use: After coarse stone, or for moderately dull knives
Passes needed: 8-12 per side
Purpose: Polish edge to razor-sharp finish, remove medium stone scratches
When to use: Final step for all knives, or sole step for touch-ups
Passes needed: 10-15 per side
Pro tip: Most kitchen knives need all three stones. Very dull knives start at coarse. Knives needing touch-ups can skip straight to fine.
Place Norton Tri-Stone on stable, flat surface. The non-slip rubber base should grip securely. Position yourself comfortably—you'll maintain this position for 10-15 minutes.
Lighting matters: Position light source above and slightly behind the stone so you can see the knife edge clearly as you work.
Apply thin film of mineral oil to coarse stone. You need just enough to create slick surface—2-3 drops spread across the stone. Excessive oil doesn't improve results.
Alternative: Water works but mineral oil prevents rust on carbon steel knives and suspends metal particles better.
The single most important skill in sharpening is maintaining consistent angle. For kitchen knives, 20 degrees is ideal.
20-Degree Angle Trick: Place knife flat on stone. Raise spine approximately height of two stacked quarters (about 3/8 inch for 8-inch blade). This creates roughly 20-degree angle. Burn this feeling into muscle memory.
Hold knife at 20-degree angle. Start with heel of blade near your body. Draw blade across stone away from you in smooth, sweeping motion, maintaining angle throughout.
Key points:
Flip knife over. Match the same number of passes on second side. Consistency between sides creates symmetrical edge.
Check your progress: Run finger (carefully) along spine-side of edge. You should feel a consistent "burr" or wire edge along the entire length. This confirms you've reached the edge on the coarse stone.
Wipe knife clean. Apply fresh oil to medium stone. Repeat the same technique—same angle, same motion—but with more passes (8-12 per side).
What's happening: The medium stone removes the coarse scratches and begins refining the edge. You're building on the work of the coarse stone, not starting over.
Final stage. Wipe knife clean. Fresh oil on fine stone. Same technique, but now with lighter pressure and more passes (10-15 per side).
The finish line: The fine stone polishes the edge to final sharpness. After this stage, your knife should slice paper effortlessly and glide through tomato skin with zero pressure.
After fine stone, you'll have a micro-burr on the edge. Remove it with 3-5 very light trailing passes per side on fine stone—barely any pressure, just the weight of the knife.
Alternative: Gently strop edge on leather belt or newspaper (5-10 passes per side). This removes burr and slightly polishes the edge.
Paper test: Hold piece of paper vertically. Slice downward with knife. Properly sharpened knife slices cleanly with minimal pressure. If knife tears or won't bite, return to fine stone for more passes.
Tomato test: The ultimate kitchen test. Place knife edge on tomato skin and draw across with zero downward pressure. Sharp knife glides through without crushing.
Wipe stones clean with paper towels. Wash knife with soap and water. Dry thoroughly. Store Norton Tri-Stone in dry location.
Result: Rounded edge that won't get sharp
Fix: Practice maintaining exact same angle throughout each stroke. Muscle memory develops with repetition. Focus on feeling the angle, not thinking about it.
Result: Doesn't actually sharpen faster, creates uneven edge
Fix: Use light to moderate pressure. The abrasive does the work, not your muscle. If you're exhausted after sharpening, you're pressing too hard.
Result: Asymmetrical edge, knife pulls to one side when cutting
Fix: Count your passes. Same number each side, every stone. Consistency creates symmetry.
Result: Can't achieve final sharpness if you skip medium grit
Fix: Use all three stones in progression for very dull knives. Only skip to fine stone for touch-ups on knives that are still fairly sharp.
Result: Edge feels sharp but breaks off immediately during use
Fix: Always finish with light trailing passes or stropping to remove the wire edge. This step transforms good edge into great edge.
At Purple Café, I maintained this schedule for 8-12 knives:
| Knife Usage | Sharpening Frequency | Stone(s) Needed |
|---|---|---|
| Daily professional use | Weekly | Fine stone (touch-ups) |
| Daily home cooking | Every 2-4 weeks | Fine stone, occasionally medium |
| Weekly home cooking | Every 2-3 months | All three stones |
| Occasional use | 2-3 times per year | All three stones |
💡 Pro tip: Regular light sharpening beats infrequent heavy sharpening. Touch-ups on fine stone every few weeks remove less metal and extend knife lifespan compared to letting knife get very dull then using coarse stone.
The Norton Tri-Stone I used for 6 years in a professional restaurant kitchen delivers exceptional results.
Read My Complete Norton Tri-Stone Review →After 6 years of sharpening 8-12 professional knives weekly at Purple Café using this exact technique, I can confirm the Norton Tri-Stone system delivers restaurant-quality results. The key is consistent angle, proper progression through the three stones, and patience to let the abrasive do its work.
Western knives sharpen at 20-22 degrees per side, Japanese knives at 10-15 degrees. After 6 years sharpening knives daily at Purple Café, I found most German chef knives (Wüsthof, Henckels) work best at 20 degrees, while Victorinox and Japanese knives prefer 15 degrees. Consistency matters more than the exact angle—maintain the same angle throughout the entire sharpening process.
Sharpen every 3-6 months for home use, or every 2-4 weeks in professional kitchens. Frequency depends on usage—if you cook daily and hone regularly with a steel, sharpen every 3-4 months. Signs you need sharpening: honing no longer restores sharpness, knife crushes tomato skin instead of slicing, or requires excessive pressure. Professional kitchens sharpen weekly because of heavy use.
Sharpening removes metal to create a new edge using whetstones or sharpeners, while honing realigns the existing edge using a steel rod. Think of honing as tune-up maintenance (do it every 2-3 uses) and sharpening as rebuilding (every 3-6 months). You can't hone away a truly dull edge—eventually you need to sharpen.
A burr is a thin metal curl that forms along the edge when you've sharpened all the way to the apex. Run your finger gently perpendicular to the edge (spine to edge, never along the edge)—you'll feel a slight catch or roughness. Once you feel a consistent burr along the entire edge, you've finished that side and can flip the knife. No burr means you haven't reached the edge yet.
Use oil—Norton tri-stone sharpeners are oil stones, not water stones. Norton recommends food-grade mineral oil or their own honing oil. Never use water on oil stones (it won't work), and don't use cooking oil or motor oil (they gum up the stone). At Purple Café, we kept a bottle of mineral oil next to the sharpening station and applied it liberally before every use.
Start with coarse grit (120-400) to establish the edge and form a burr, progress to medium (800-1000) to refine, then finish with fine (4000-8000) for polishing. The Norton IM313 tri-stone system includes coarse Crystolon, medium Crystolon, and fine India—perfect for kitchen knives. Only use coarse if the knife is very dull or damaged; otherwise start with medium.
Common causes: not forming a burr (you haven't reached the edge), inconsistent angle (changes mid-stroke ruin the edge), starting with too fine a grit (switch to coarse), or not removing the burr at the end. If you've done 50+ strokes without feeling a burr, your grit is too fine. Drop down to coarse grit and apply more pressure.
Use the coin trick—stack two quarters under the spine of an 8-inch chef's knife, which creates roughly 15 degrees. Feel this angle, then remove the coins and replicate it. Lock your wrists and move from the shoulders, not the wrists. After 6 years of daily sharpening at Purple Café, muscle memory takes over, but beginners benefit from angle guides or the coin method.
The burr is removed by progressing through finer grits with lighter pressure—each finer stone creates a smaller burr until it's microscopic. On your finest stone, use very light strokes (just the weight of the knife), alternating sides after each stroke. Finish with 5-10 passes on a leather strop or the back of a leather belt. The burr should break off cleanly.
The tomato test: without holding the tomato, gently rest the knife on the skin and slice with no downward pressure—a sharp knife glides through. Or try the paper test: hold paper vertically and slice downward—sharp knives cut cleanly without tearing. At Purple Café, we used the arm-hair test (knife should shave arm hair), but tomato-slicing is safer and equally reliable.
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Professional Chef • 24 Years Professional Kitchen Experience
Professional chef with 24 years of restaurant experience including Pizzaiolo at Purple Café, Kitchen Manager at Mellow Mushroom, and line positions at Feierabend, Il Pizzaiolo, and Paragary's. A.A.S. Culinary Arts from Seattle Central College, B.S. Business Administration from University of Montana. Every product tested through real professional kitchen use or extensive long-term home testing.
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