folding knife

Sharpen a Knife With a Knife Sharpener

To sharpen a knife with a knife sharpener, draw the blade through the sharpener's abrasive slot at a consistent angle of 15 to 20 degrees per side, applying even pressure from heel to tip, for 3 to 5 passes per side until the cutting edge slices cleanly through paper. A knife sharpener removes a thin layer of steel from the blade's bevel to rebuild a sharp edge, and 4 sharpener types serve this purpose: manual pull-through sharpeners, electric sharpeners, guided sharpening systems, and whetstones (sharpening stones). This guide covers how knife sharpeners work, choosing the right sharpener, sharpening tools, blade preparation, step-by-step sharpening for kitchen and pocket knives, common mistakes, sharpening frequency, knife storage, and knife maintenance.

How Do Knife Sharpeners Work?

Knife sharpeners work by grinding the blade's bevel against an abrasive surface until both sides of the edge meet at a clean apex. The abrasive material removes a controlled amount of steel from the bevel, and the process creates a burr — a thin lip of steel that flips to the opposite side of the blade when the abrasive reaches the cutting edge. Removing the burr with light alternating strokes or a leather strop produces a finished sharp edge.

What Abrasive Materials Do Knife Sharpeners Use?

Knife sharpeners use 4 main abrasive materials: tungsten carbide, ceramic, diamond, and natural or synthetic stone. Tungsten carbide rods sit in the coarse sharpening slot of manual pull-through sharpeners and remove steel quickly for dull knives. Ceramic rods sit in the fine or honing slot and polish the edge after sharpening. Diamond-coated plates cut faster than ceramic and last longer than natural stone. Whetstones come in grit ratings from 200 (coarse) to 8,000+ (polishing), measured in Japanese Industrial Standards (JIS) grit.

What Is the Difference Between Sharpening and Honing?

Sharpening removes steel from the blade to create a new edge, and honing realigns the existing edge without removing steel. A honing rod (also called a honing steel or sharpening steel) straightens microscopic bends and rolls in the cutting edge that develop during normal use. Honing maintains a sharp knife between sharpening sessions but does not restore a dull knife.

What Tools Are Needed to Sharpen a Knife?

Sharpening a knife requires 3 items: a knife sharpener, the dull knife, and a damp cloth for wiping metal shavings from the blade after sharpening. The 4 sharpener types differ in speed, control, and price:

• Manual pull-through sharpener: 2 to 3 slots with tungsten carbide and ceramic rods, costs $10 to $30, sharpens a knife in under 60 seconds
• Electric knife sharpener: motorized abrasive wheels in 2 to 3 stages, costs $30 to $150, sharpens a knife in 30 to 60 seconds
• Guided sharpening system: a clamp-and-stone jig that holds the blade at a fixed edge angle, costs $50 to $300, provides the most repeatable angle control
• Whetstone (sharpening stone): a flat abrasive block soaked in water or oil, costs $15 to $100 per stone, requires manual angle control at 15 to 20 degrees per side

Which Sharpener Is Best for Beginners?

A manual pull-through sharpener is the best sharpener for beginners, because the sharpener sets the edge angle automatically and requires only a pulling motion through the slot. The OXO Non-Slip Knife Sharpener has 2 slots — one with tungsten carbide rods for sharpening and one with ceramic rods for honing — and a non-slip base that holds the sharpener steady on a kitchen countertop.

How to Prepare a Knife for Sharpening

To prepare a knife for sharpening, clean the blade, inspect the edge, and set up the sharpener on a stable surface.

Cleaning the Blade Before Sharpening

Wipe the blade with warm soapy water, then dry the blade with a clean cloth. Grease, food residue, and grit clog abrasive surfaces and produce uneven scratch patterns during sharpening. Clean both sides of the blade from spine to edge, keeping fingers behind the cutting edge.

Inspecting the Blade

Hold the blade under a bright light and look for chips, flat spots, or a rolled apex along the cutting edge. A sharp edge reflects little light, and a dull edge reflects a bright line along the apex. Chips deeper than 0.5 millimeters (0.02 inches) require a coarse abrasive or professional sharpening to remove.

Setting Up the Sharpener Safely

Place the sharpener on a flat, stable surface with good lighting. Hold the sharpener with the non-dominant hand and keep the dominant hand on the knife handle. Keep fingers behind the cutting edge at all times, and position the blade perpendicular to the body when repositioning the knife.

How to Sharpen Kitchen Knives With a Pull-Through Sharpener

To sharpen kitchen knives with a pull-through sharpener, follow 6 steps:

1. Place the sharpener on a flat surface and hold the handle with the non-dominant hand
2. Center the heel of the knife in slot 1 (the coarse sharpening slot) and tilt the blade so the tip points slightly downward
3. Pull the blade toward the body through the slot in one smooth stroke, applying firm and even pressure from heel to tip
4. Repeat the pull stroke 3 to 5 times through slot 1 until metal shavings appear or the blade glides more smoothly
5. Move the knife to slot 2 (the honing slot) and pull the blade through 2 to 4 times with the same heel-to-tip motion
6. Wipe the blade with a damp cloth to remove metal shavings, then rinse with warm soapy water and dry immediately

How to Sharpen a Knife With a Whetstone

To sharpen a knife with a whetstone, soak the stone in water for 5 to 10 minutes, place the stone on a non-slip base, hold the blade at 15 to 20 degrees against the stone, and draw the blade from heel to tip in smooth strokes. Start on the coarse side (800 to 1,000 grit), apply consistent pressure for 5 to 10 passes per side until a burr forms along the full edge, then flip the stone to the fine side (3,000 to 6,000 grit) and repeat with lighter strokes to remove the burr and polish the edge.

How to Sharpen a Knife With an Electric Sharpener

To sharpen a knife with an electric sharpener, turn on the sharpener, draw the blade through the coarse slot at a slow and steady pace for 2 to 3 passes, then draw the blade through the fine slot for 1 to 2 passes. Electric sharpeners use motorized abrasive wheels that spin against the blade, and the slots set the edge angle automatically. Pull the blade at a slow pace of 1 to 2 seconds per pass to avoid overheating the steel.

How to Sharpen a Pocket Knife With a Sharpener

To sharpen a pocket knife with a sharpener, lock the blade open, hold the handle firmly, and draw the blade through a pull-through sharpener or across a whetstone at 17 to 22 degrees per side. Pocket knife blades are shorter than kitchen knives, typically 2.5 to 4 inches (63.5 to 102 mm), so each stroke covers the full blade length in one pass. Pocket knife steel is often harder than kitchen knife steel, rated at 58 to 62 on the Rockwell Hardness Scale C (HRC), so sharpening requires more passes on a fine abrasive.

Which Knives Can a Knife Sharpener Sharpen?

A standard pull-through knife sharpener sharpens stainless-steel knives with a non-serrated (plain) edge, including chef's knives, santoku knives, paring knives, utility knives, carving knives, and pocket knives. Serrated knives require a tapered diamond rod that fits into each serration. Ceramic knives require a diamond-grit sharpener, because ceramic blades are harder than steel at 9.0 to 9.5 on the Mohs hardness scale and chip under standard tungsten carbide or steel abrasives.

Common Knife Sharpening Mistakes to Avoid

Knife sharpening has 8 common mistakes:

• Changing the edge angle mid-stroke, which rounds the bevel and creates a dull edge
• Applying too much pressure, which removes more steel than needed and shortens the blade's life
• Skipping grit steps, which leaves coarse scratch marks that weaken the edge
• Stopping before a burr forms along the full edge, which means the bevel did not reach the cutting edge
• Sharpening a dirty blade, which clogs the abrasive with grease and food residue
• Grinding the tip incorrectly, which rounds off the point
• Using a pull-through sharpener on thin Japanese knives with a 10 to 15 degree edge angle, which removes too much steel
• Confusing honing with sharpening and expecting a honing rod to restore a dull blade

How Often Should Knives Be Sharpened?

Knives should be sharpened 2 to 4 times per year for daily kitchen use, and 1 to 2 times per year for occasional use. A knife used 3 or more times per week for cutting meat, vegetables, and fish dulls faster and needs sharpening every 2 to 3 months. Hone the blade with a honing rod before each cooking session to maintain the edge between sharpening sessions. Professional sharpening every 2 to 3 years restores the factory bevel geometry and corrects any uneven wear from home sharpening.

How to Store Knives to Keep Them Sharp

Store knives in 4 ways that protect the cutting edge: a knife block, a magnetic wall strip, a drawer organizer with individual slots, or blade sheaths (protective covers). Storing knives loose in a drawer with other utensils chips and dulls the cutting edge each time the drawer opens. Mount a magnetic strip with the spine of the blade touching the magnet first, not the edge, to avoid dulling the blade during placement.

How to Care for and Maintain Knives

Knife care follows 5 practices that extend blade life and sharpness:

• Hand wash knives with mild dish soap and warm water immediately after use, because acidic foods such as tomatoes, onions, and citrus corrode the steel
• Dry knives immediately with a cloth or paper towel, because air drying causes rust and water spots on the blade
• Cut on wood or plastic cutting boards, because glass, stone, and ceramic boards dull the edge and chip the blade
• Keep knives out of the dishwasher, because the high water temperature and jostling against other items damage the blade and handle
• Remove rust by soaking the blade in white vinegar for up to 24 hours, then scrubbing with an abrasive sponge, rinsing, and drying immediately