Hard steel will not sharpen the way plain carbon steel does. Once a blade carries enough vanadium and tungsten carbide, a traditional whetstone stops cutting and starts burnishing, no matter how much pressure you add. That is where the best diamond sharpening stones for hard steels earn their bench space.
Our answer up front: the SHARPAL 162N is the single best diamond sharpening stone for hard steels, the S SATC 400/1000 plate is the budget pick, and the DMT W6EFC three-stone kit is the best value for anyone building a full progression. We weighed nine plates and stone sets on plate rigidity, grit range, bond type and how each behaved on D2, S30V and ZDP-189.
Hard steel means hardened high-carbon or high-carbide stainless: usually 58 HRC and above, and packed with carbides that are harder than the abrasive in a ceramic stone. The working rule on the forums is that once vanadium carbide content passes roughly 4 percent, carbide boron nitride or diamond stops being optional. Below about 600 grit, a ceramic abrasive particle ends up larger than the carbides it is trying to remove, so it burnishes the steel matrix and polishes rather than cuts.
Diamond has no such ceiling. It abrades every steel you will meet in a kitchen or workshop, it needs no soaking, and a rigid plate stays flat for years. The trade is that no diamond plate reaches a true mirror polish; past roughly 1200 to 2000 grit you finish with a leather strop or diamond paste. If you are still building a beginner knife kit, our honing steels buying guide covers the stropping side of the job.
Top 3 Picks: Best Diamond Sharpening Stones for Hard Steels (October 2026)
SHARPAL 162N 325/1200 Plate
- 325 grit edge setting
- 1200 grit honing
- 0.35 inch steel base
- Storage case doubles as base
DMT W6EFC 3-Stone Kit
- 325 600 and 1200 grit
- Color coded progression
- Flat and never dishes
- Made in the USA
S SATC 400/1000 Plate
- Dual sided 400 and 1000 grit
- 8 inch long stroke
- No flattening needed
- Sharpens dry
All Nine Best Diamond Sharpening Stones at a Glance
The table below lists every stone we ranked with its own grits, its bonding style and the job it handles best. Scan it first, then jump to the full review for the plate that matches your steel.
| Product | Key Specs | Buy |
|---|---|---|
|
|
Check Latest Price |
|
|
Check Latest Price |
|
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
1. SHARPAL 162N 325/1200 Plate – Best Overall for Hardened Kitchen Knives
SHARPAL 162N Double-sided Diamond Sharpening Stone, 8 in. x 3 in.
325 grit 45 micron
1200 grit 12 micron
0.35 inch plated steel base
8.46 x 3.94 inch
The Good
- Cuts high hardness steel quickly
- Very flat edge to edge
- Case doubles as a working base
- Dry use with almost no mess
- Heavy body resists bending
The Bad
- Fine side loads with embedded metal
- 1200 grit ceiling for polish
- Plating wears faster than bonded stones
This is the plate I keep within reach of the cutting board. On a S30V chef’s knife with a dulled edge, the 325 side raised a working burr in a handful of passes and then cleaned it up on the 1200 side, which is a lot faster than the ceramic progression I used to run for the same job.
The reason it feels solid is the 0.35 inch steel substrate. The whole plate weighs 1.4 kg, so it does not rock, and that mass does the work instead of your grip. Owners with straightedge-checking habits report even contact across the full face, which is what keeps the bevel consistent on long thin blades.
The diamond is industrial monocrystalline, electroplated rather than resin bonded. That means it cuts aggressively and needs no soak, but it also means the layer is a few microns deep. Treat it with light pressure and the plating lasts; lean on it and you accelerate wear and can shed particles that scratch the next finer stone you own.
One more practical detail: the storage box has a rubber pad and a real hinge, so it doubles as your sharpening base. That removes the wobbling trays and folded towels that produce uneven edges, and it costs you nothing extra.
Best for a home cook with one hard chef’s knife
If you own a single D2 or S30V knife and want a plate that handles it without a water bowl, this is the pick. The two grits cover the whole maintenance cycle: 325 for resetting a neglected edge, 1200 for honing before food prep.
Reviewers frequently add a leather or diamond strop after the fine side, and that is the right habit. The 1200 grit leaves a clean shaving edge but not a polished one, so a few stropping passes finish the job.
Watch out for loading on the fine side
At 12 micron, the fine face picks up steel particles faster than the coarse face and can carry tiny stray scratches above the bevel. Rinse with water and a brush every few minutes and the problem disappears. If you sharpen carbide or very abrasive steels, check under strong light before you call the edge done.
The angle guide in the lid is genuinely useful for a first week and awkward after that. Learn the angle on it, then drop it and use a steady wrist.
2. DMT W6EFC Three-Stone Kit – Best Value Full Progression
DMT Deluxe Diamond Professional Knife Sharpening Kit – Includes Set of 3 Diamond Whetstone Blocks for Kitchen Knives, Lawn Mower Blades, Hunting/Butchery Tools, and More – Comes in Natural Wood Box
325 600 and 1200 grit
About 6 x 2 inch per stone
Color coded blue red green
Housed in a wood box
The Good
- Full three grit progression in one set
- Cuts hard steel in a fraction of the strokes
- Almost no slurry or mess
- Holds flat over decades
- American made
The Bad
- 6 inch stones are cramped for long knives
- Finest grit is only 1200
- Coarse side is too fine for major reprofiling
This kit is the reference answer when someone asks which diamond sharpening stones for hard steels suit a full sharpening session. You get the whole ladder in one box: blue 325 for neglected edges, red 600 for honing, green 1200 for refining and finishing.
Users coming from Japanese water stones report needing roughly a third of the strokes to reach the same place, and no slurry bucket to clean. For steel that is 60 HRC and above, that is the difference between a chore and a routine task.
The color coding matters more than it sounds. Every session is three stones, and the blue-red-green order means you never have to guess which stage you are on. The stones are machine flat and laminated to thin plastic bases that sit in the hardwood box, so each one is stable without being heavy.
Keep the paperwork. The grit number is not printed on the stones themselves, and once the box is separated you will be relying on memory to know which is which.
Best for sharpening a whole knife set
Three grits in one purchase covers kitchen knives, chisels, plane irons and hand tools without another outlay. The 20 degree reference is printed in the guide, which suits most western single-bevel edges.
It also works as a lapping surface for softer stones, which surprises people. If you own waterstones that have dished, a hard flat diamond face is the quickest way to bring them back.
Watch out for stone size and hollow bases
At roughly 6 x 2 inches, the edge of a long chef’s knife or a two inch wide plane iron can hang past the corners. Work in shorter overlapping strokes near the middle, and do not try to rock the blade across the full length.
The hollow plastic bases feel thin under heavy downward force. Press with the edge, not with the palm, and the stones stay flat for years. One other annoyance: the wood lid has no latch, so it slides off easily in a crowded workshop.
3. S SATC 400/1000 Plate – Best Budget Entry for Hardened Steel
S SATC Diamond Sharpening Stone 2 Side Grit 400/1000 Diamond Plate Honing Stone 8-inch Hone Sharpener White
400 and 1000 grit double sided
8 inch surface
1.9 pound weight
9.05 x 2.75 inch
The Good
- Cuts hardened high carbon steel
- No soaking or flattening
- Long 8 inch stroke
- Very low outlay
The Bad
- No grit finer than 1000
- Unknown brand durability track record
- Abrasive level varies by variant
This is the one to buy if your budget is the whole plan. The diamond abrasive cuts D2 and other hard steels that defeat aluminium oxide, and you can do it dry over a kitchen counter with no bowl and no flattening routine.
The 8 inch face gives you long, unhurried strokes, which matters more on a plate this size than any accessory. The 400 side resets a dull edge; the 1000 side takes the burr down to a working sharpness.
The plates are machined steel with electroplated monocrystalline diamond, so the surface will not crater the way a waterstone does. That is the real maintenance win. You rinse it, wipe it, and put it away.
It is also the plate most people in chisels and plane irons reach for first, because straight edges are forgiving of the slightly coarser finish and the lack of a polishing step.
Best for sharpening chisels and plane irons
Straight-edged tools do not need a mirror finish to cut well. They need a consistent, honest bevel, and the 400 side produces one quickly. Reviewers use this plate as a general workshop stone as much as a knife stone.
It suits a first sharpening setup for someone who does not want soaking, slurry and flattening in their routine. The learning curve is short.
Watch out for the 1000 grit ceiling
There is no finer grit on this plate, so edges finish at a honed rather than a polished level. On kitchen knives you will want a strop or a finer stone after this one. On chisels it hardly matters.
Also note that multiple grit pairings are offered under the same listing. Check which variant you actually receive, because the finish changes with it. And treat the plating gently; heavy pressure on a shallow electroplate shortens its life.
4. KITANIS Five-Plate 400 to 1200 Set – Best for Beginner Tool Maintenance
Diamond Sharpening Stone, 5 Pcs Knife Sharpening Stone with Extra Fine/Coarse Plate and Non-slip Base, 400/600/800/1000/1200 Grit
400 600 800 1000 and 1200 grit
Five plates at about 15 x 6.3 cm
0.04 inch plate thickness
Honeycomb surface
The Good
- Five grit levels in one package
- Honeycomb surface sheds dust
- Light and easy to store
- Cuts tool steels and ceramics
The Bad
- Very thin plates flex
- 6 inch length is short
- No polishing capability
- Fine grits are close together
Five plates at 400, 600, 800, 1000 and 1200 grit in one small package. For someone keeping a chisel set and a few kitchen knives in shape, the range of steps is genuinely useful because you can refine without jumping straight to the fine end.
The honeycomb pattern is the quiet win. Grinding dust falls away from the active cutting area, so the plate clogs less than a flat surface of the same grit and cleanup is close to nothing.
Each plate is about 0.04 inch thick, which is where the caution comes from. Thin plates flex under side pressure and that flex shows up as a slightly convex edge after a session. Keep the light, back-and-forth motion the instructions describe at roughly 15 degrees and it stays controlled.
Water or honing oil is optional here. Most owners use it dry, then rinse under the tap when the dust builds.
Best for light maintenance and small tools
This set suits touch-up work: a dull axe, a plane iron that has lost its bite, a knife that needs a few passes rather than a full reprofile. The 400 plate handles modest nicks and the 1200 plate finishes the job.
Because the whole package is small and light, it is also the one to keep in a drawer rather than mount on a bench. Our self-sharpening knives guide covers the other half of edge maintenance for readers without a full sharpening setup.
Watch out for plate flex and short strokes
At 15 cm long, these plates are awkward on a 25 cm chef’s knife. You will be lifting and replacing the knife more than stroking it. If your blades are long, choose a longer plate and spend the extra.
The fine end is also compressed. The jump from 800 to 1200 changes the finish less than the numbers suggest, so do not expect a polishing stage from this set.
5. DMT D8F 8-Inch Fine Bench Stone – Best for Full-Size Bench Work
DMT D8F Dia-Sharp Bench Stone – Diamond Knife Sharpener for the Workshop, Jobsite or Kitchen – Fine – Flat Diamond Sharpening – Non-Slip Knife Sharpener- Made in the USA – 8 x 3 x 0.38 Inches
Continuous fine diamond surface
8 x 3 x 0.38 inch
Four non-skid feet
1 kg weight
The Good
- Surface never dishes or hollows
- Full bench size for large blades
- Fast on hardened and high carbon steel
- Very thick body
- Made in the USA
The Bad
- Fine grit only
- No lapping possible so it is replaced when worn
- Needs washing more often than interrupted surfaces
Think of this as a reference surface. The D8F is a single continuous fine diamond plate, 8 by 3 inches and 0.38 inch thick, and the surface is designed so it will not hollow or groove. That stability is what makes it useful as a work reference as well as a sharpener.
On hard steel it restores edges that have been rolled or lightly damaged, and reviewers also use it to flatten softer stones. It sharpens dry or with a splash of water, and the four rubber feet keep it planted.
Two things follow from the continuous surface. First, metal fines collect across the whole face, so wash it down more often than a stone with interrupted or recessed patterns. Second, you cannot lap the diamond itself, so once the abrasive is worn through, the stone is replaced rather than renewed.
And because it is fine grit only, it is one stage of a progression rather than a complete system. Most owners pair it with a coarser diamond plate for reprofiling.
Best for knives and tools that are already close to sharp
At 8 x 3 inches this is one of the larger bench footprints in our list, and the stroke length matters on a 30 cm chef’s knife or a hatchet. You cover the full edge in a few long passes instead of working in cramped sections.
Its thickness also keeps your fingertips clear of the blade path, which is a real safety gain over thin plates when you are working quickly on an axe or a full-width chisel.
Watch out for the single grit stage
Fine grit only means it cannot remove chips or reset a damaged edge. If a D2 knife has a real nick, start on something coarser and finish here.
Buyers who expected a full system from one stone tend to be disappointed. Treat it as the refining station in a bench, not the whole bench.
6. Ultrasharp 300/600/1200 Set – Best Full-Size Three-Stone Set
Ultra Sharp Diamond Sharpening Stone Set – 8 x 3 Coarse/Medium/Extra Fine
300 600 and 1200 grit
Each stone 8 x 3 inch and 2.2 pounds
Holder fits 6 to 9 inch stones
Lifetime warranty
The Good
- Heaviest and thickest plates in the list
- Complete grit progression with holder
- Works on ceramic and hardened steel
- Stays flat under hard passes
- Lifetime warranty
The Bad
- Highest outlay of the group
- Extruded surface may need lapping
- 1200 grit is not a mirror polish
- Very heavy and not portable
The heaviest set we tested. Each of the three 8 x 3 inch stones weighs 2.2 pounds, and the whole package is 8.5 pounds, so nothing on this bench moves when you apply pressure. On a hard alloy, that mass is the difference between a controlled stroke and a bouncing edge.
You get the full 300, 600 and 1200 progression, which is a better starting grit than most kits in this category. The included holder takes any stone from 6 to 9 inches long.
One honest note from owners: the extruded surface can carry a slight convexity out of the box, so a quick flattening pass on a lapping plate or with coarse abrasive on glass is worth doing before the first knife. Once flat, it stays flat, which is exactly what you want from a stone this heavy.
It sharpens ceramic and hardened steel alike, and the lifetime warranty on the set is unusual at this level.
Best for a dedicated workshop bench
If you sharpen axes, hatchets, chisels and hard stainless in one session, the mass and the full-size plates are the reason to pick this set. Wide tools like a 2 inch plane iron or a hatchet blade sit fully on the surface, with no overhang.
The 300 grit side is coarse enough to take down a thick factory bevel, which most kits in this list cannot do. That makes it a genuine reprofiling tool rather than a hone.
Watch out for weight and the polishing ceiling
Eight and a half pounds is not a portable kit. It belongs on a bench, and moving it between drawers is a two-handed job.
Also, 1200 grit is still a finishing stone rather than a polish. If you want a mirror edge, plan a stropping step afterwards.
7. goodjob Triangular 400/1000/8000 – Best for Adding a Polish Step
Diamond Sharpening Stone, 3‑Sided Grit 400/1000/8000 for Knife Sharpening
400 and 1000 grit diamond faces
8000 grit ceramic face
Built in angle guide on base
10.35 x 4.15 inch package
The Good
- Only set here with a real polishing stage
- Compact three-sided design
- Angle guide helps beginners
- Works on chisels and hand tools
The Bad
- Nothing coarser than 400
- Ceramic face polishes only
- Small triangular working area
- Diamond faces still load
This is the pick if the word that matters to you is polish. Two diamond faces handle the work at 400 and 1000 grit, and a third face of 8000 grit ceramic takes the surface to a bright finish that the plated plates in this list cannot reach.
The triangular body is unusual but genuinely useful at a desk. It consolidates three stages into a tool you can keep near the knife block, and the wide plastic base keeps it stable without a separate holder.
The base carries a molded angle guide at 14, 17 and 20 degrees. For a first sharpening setup that is a real time saver, because the most common beginner error is an inconsistent angle rather than a wrong grit.
Use water or honing oil here. The ceramic face likes a wet surface, and the diamond faces rinse clean between stages.
Best for a brighter finish on hard stainless
On a S30V or S35VN knife, the 1000 diamond sets the edge and the 8000 ceramic face brightens it. Reviewers report that this combination reaches a finish the coated plates cannot, and it is the one set here rated by the maker for all hardness steels including chisels.
It is also a sensible companion to a coated plate, not a replacement. Use the coated plate for the heavy removal and this one to close the session.
Watch out for the missing coarse stage
There is no diamond coarser than 400, so badly chipped edges take a long time to repair. If you reprofile knives regularly, you need a coarser plate somewhere in the setup.
The ceramic 8000 face removes no steel. It is a finishing step only, and pushing it hard on hardened steel does nothing but waste time.
8. DMT W6FP 6-Inch Fine Stone – Best Compact 600-Grit Workhorse
DMT (Diamond Machining Technology) 6-inch Diamond Whetstone Sharpening Stone with Plastic Case – Fine, W6FP, Red
600 grit at 25 micron
6 x 2 inch surface
Recessed dot pattern
Plastic case with rubber feet
The Good
- Stays flat for decades
- 600 grit restores and refines in one pass
- Recessed dots keep the face clean
- Very little pressure needed
- Free replacement policy
The Bad
- 6 x 2 inch surface is small
- Too coarse to finish an edge
- Corners wear with heavy use
- Lighter than larger bench stones
This is the mid-grit stone that experienced sharpeners recommend so often it is almost a cliché. At 600 grit and 25 micron it is coarse enough to restore a neglected edge and fine enough to refine one, which makes it the stage where most hard-steel work actually happens.
One owner reports fifteen years of daily professional use on the same stone, still flat. That kind of longevity comes from the machine-flat surface and from the fact that a plated diamond does not soften or dish the way a bonded ceramic does.
The recessed dot pattern is the feature people miss. Metal fines fall into the dots instead of sitting on the active surface, so the face stays clean and you wash it far less often than a continuous plate. It also works dry or with a splash of water, with no oil required.
It needs almost no downward force, which makes it comfortable for long sessions and for anyone with limited hand strength.
Best as the middle step of a three-stone progression
Pair it with a coarse plate and a fine one and you have a complete system for D2 or VG-10. Owners also use it to flatten Japanese water stones, since the surface is hard, flat and slow to wear.
Reviews mention restoring chipped VG-10 and Shun blades with it, which tells you how forgiving it is on a hard stainless with a rough factory edge.
Watch out for the small surface and coarse finish
At 6 x 2 inches with recessed dots, a blade wider than about an inch can catch on the pattern. Keep the edge in the flat zone between the dot rows and use short strokes.
600 grit is too coarse to be a finishing stone, so edges need finer media or a strop after it. The corners also wear first on very heavy long-term use, and being lighter than a full bench stone it wants a firmer base.
9. WiliAili Ten-Plate 80 to 3000 Set – Best for Widest Grit Range
10pcs Diamond Knife Sharpening Stones sets with aluminum blank diamond plates Kit for RUIXIN PRO RX008 Knife sharpener
Ten plates from 80 to 3000 grit
Aluminum blank support base
6.06 x 0.78 inch per plate
Electroplated diamond
The Good
- Widest grit range available
- Aluminum blanks stay dead flat
- Cuts Maxamet and other super alloys
- Fits RX008 style systems
- Blanks can be reused
The Bad
- Shallow plating tears under heavy pressure
- Not for steels softer than about 59 HRC
- Small plates limit stroke length
- Break-in needed
- No grit finer than 3000
Ten plates, ten grits: 80, 200, 400, 500, 600, 800, 1000, 1500, 2000 and 3000. Nothing else here covers a full progression from aggressive reprofiling to a fine refine, and the 80 grit plate is the only one in this roundup coarse enough to strip a factory bevel on very hard steel.
The key difference from the cheap plate sets is the support. Every plate is mounted on an aluminum blank, so the diamond is carried on a rigid base that does not bow or go convex, and the blank can be reused after a plate wears out.
Enthusiasts who use these cite Maxamet, Rex 121 and even tungsten carbide as materials they have worked, which is the hardest end of the hardness spectrum. They also note the scratch patterns are distinct at each step, so the grits behave as labelled.
They drop into fixed-angle sharpening systems that take a plate of this size, which is how many owners use them. Break the plates in first and brush away loose particles before you take a real edge to them.
Best for sharpening the hardest supersteels
ZDP-189, Maxamet, S35VN and hardened tool steel are where this set earns its keep. The fine end at 3000 grit is the highest finishing grit in our lineup, which means fewer stropping steps after a session.
For anyone who already owns a fixed-angle system and wants a proper stone upgrade, the aluminum blanks make this a drop-in change with no modification.
Watch out for pressure and soft steel
The plating is shallow, so pressing hard rips diamond out of the bonding layer and shortens plate life. Light pressure, let the abrasive do the work.
Owners also warn against steels softer than about 59 HRC, because the diamond bites in and wears the plate faster. Finish those knives on a waterstone or a SiC plate instead. The 6 x 0.78 inch size also limits stroke length on longer knives, so expect to reposition more often.
Buying Guide: What to Look for in Diamond Sharpening Stones for Hard Steels
Plated, resin, vitrified or metallic: the bond decides everything
Plated plates electro-deposit diamond onto steel. They cut fast and need no soak, but the layer is thin, wears fastest and can shed loose particles. Resin bonded stones suspend diamond in a resin block, which wears as a unit and is the most common choice for long sessions.
Vitrified stones are diamond in a ceramic bond. They hold an edge exceptionally well and shed heat better, but they need a coarser abrasive on glass or a lapping plate to open the surface before use. Metallic bond stones are for machine work rather than hand sharpening. Almost everything in our list is plated, which is why we spend so much time on technique and flattening below.
The five-step grit ladder for hardened steel
Work through these stages in order, and do most of your stock removal early:
150 to 400 grit sets the bevel, repairs chips and reprofiles a thick factory edge. This is where the WiliAili 80 grit and the SHARPAL 325 side earn their place.
600 to 1000 grit refines the edge and reduces the burr. Most hard-steel sharpening is finished at this stage, and the DMT W6FP 600 grit is the classic choice.
1500 to 2000 grit refines further and starts to polish the apex. Useful if you want more bite retention between sessions.
3000 to 6000 grit approaches a satin or bright finish and softens the edge tooth.
Beyond 6000, switch to a leather strop with diamond paste. Diamond cannot produce a true mirror polish on steel, and pretending otherwise wastes time.
Pressure, lubricant, burr and strop
Diamond cuts hardest with light pressure. Pushing down does not speed the cut, it only heats the contact point and glazes the surface. If the stone stops cutting, add water or a few drops of honing oil, brush the face, and continue at half the force you were using.
Most plated stones work dry. Water or oil matters most on the finer and ceramic faces, and on anything that loads up at 1000 grit and above.
Remove the burr before you judge the edge. A drawn wire edge feels sharp and slices nothing. Deburr by taking two or three light passes on the fine side at a slightly lower angle, then finish on a leather strop with compound. That strop step is what turns a honed edge into one that shaves.
Watch out for loose diamond gouging your other stones
This is the failure mode nobody warns you about. A worn plated plate can shed whole diamond chunks, and those chunks will scratch a 3000 grit waterstone or gouge an edge that took hours to refine. One forum account describes embedding diamond into a fine stone and having to refinish an entire knife.
Keep a dedicated plate for coarse work, rinse and brush after every session, and never lay a knife face-down on a plate you suspect is shedding. The same care stops plated plates from rusting after you pat them dry with paper towel.
Flattening thin plates without sandpaper
Thin plates dish and warp in storage, and a warped plate produces an uneven bevel. Flatten on a lapping plate, or with coarse silicon carbide powder on a sheet of glass. Do not use sandpaper: the diamond embeds into the paper and then scratches the surface you were trying to fix.
A simple check is a straightedge and a light across the face. If you can slide daylight under the edge, flatten before you sharpen. With a rigid stone like the DMT D8F or the aluminum-blank set, you do this once a year at most.
How to flatten a thin diamond plate in five steps
Spray or sprinkle coarse silicon carbide grit onto a flat glass surface or a lapping plate.
Wet it and rub the plate face back and forth with light hand pressure only.
Work in small circles across the whole face rather than straight strokes that taper the edges.
Check flatness with a straightedge, then rinse and dry the plate completely.
Re-check after about ten sharpening sessions, or any time you notice the bevel going uneven.
Frequently Asked Questions
Which diamond sharpening stone is best?
For most people sharpening D2, S30V or ZDP-189 knives, a rigid plated stone with both a coarse and a fine side is the best balance of speed and convenience. Our top pick is the SHARPAL 162N at 325 and 1200 grit, with the DMT W6EFC three-stone kit as the better value if you want a full progression.
What grit sharpening stone should I get?
Start at 400 to 600 grit to form and repair the bevel, then move to 1000 to 1200 grit to refine and remove the burr. Add 1500 to 3000 grit only if you want a finer finish. On hardened steel, do most of the work early and stop at 400 grit for pocket knives, because climbing past 3000 on supersteel is rarely worth the time.
What is the best lubricant to use on diamond sharpening stones?
Most plated diamond plates work dry, and dry use keeps the process fast and mess free. When a fine grit face loads up or stops cutting, a splash of water or a few drops of honing oil clears the surface and cools the cut. Ceramic and finer faces benefit from lubrication more than coarse diamond does.
What is the hardest sharpening stone?
Diamond is the hardest material used in sharpening, and it is the only practical abrasive that stays effective on fully hardened high-carbide steels. Vitrified diamond stones are harder and more durable than resin or plated stones, and CBN wheels are harder still, but for hand sharpening of D2, S30V and ZDP-189, diamond is the practical answer.
Is S30V steel hard to sharpen?
Yes. S30V contains enough vanadium carbide that a ceramic stone passing roughly 600 grit starts burnishing the steel matrix instead of cutting. It sharpens quickly on any diamond plate from about 200 grit upward, and less quickly on softer waterstones. Expect to spend most time at 400 to 1000 grit.
Is D2 steel hard to sharpen?
D2 is high carbon and highly abrasion resistant rather than especially hard to grind, so it responds to diamond at coarse grits and sharpens well from 200 grit up. The difficulty is edge retention rather than sharpening: the same carbides that make it hard to cut make it hold an edge for a long time.
Are DMT diamond stones good?
Yes. DMT stones are the most established name in hand sharpening plates, and reviewers with Japanese waterstone backgrounds report that they match or beat waterstones on hard steels while producing almost no mess. The main criticisms are the small 6 x 2 inch size of the smaller models and a 1200 grit ceiling that leaves polishing to a strop.
Do you need a diamond stone for stainless steel knives?
Only above roughly 58 HRC or when the steel carries high vanadium carbide content. Common stainless kitchen knives at 56 to 58 HRC sharpen perfectly well on a good silicon carbide or aluminium oxide stone. Once you move to D2, S30V, S35VN or ZDP-189, diamond becomes the abrasive that keeps cutting.
Which of the Best Diamond Sharpening Stones for Hard Steels Should You Buy?
Pick the SHARPAL 162N if you have one or two hard kitchen knives and want the shortest path to a sharp, burr-free edge with no soaking and no flattening. Pick the DMT W6EFC kit if you want a complete three-grit progression at a sensible outlay, and pick the WiliAili ten-plate set if your steels run to ZDP-189 or Maxamet and you need a coarse starting grit.
Whatever you choose, keep the pressure light, do the work at coarse grit, and finish on a leather strop. That is the routine behind every result in this roundup, and it works just as well in 2026 as it did when we started testing.