Hard steel punishes ordinary whetstones. A powder metallurgy blade in the S30V, S35VN or D2 family will load a waterstone surface faster than you can flatten it, and a high carbide alloy like Maxamet can leave a 1000 grit stone dished before a single full-length stroke is finished. A diamond sharpening stone is the answer, because industrial diamond particles do not lose hardness to abrasion the way abrasive grit does.
This roundup covers the best diamond sharpening stones for hard blades currently on the market: electroplated plates, bench stones, multi-grit sets and a compact field sharpener. I compared the grit range, substrate, surface pattern and real-world cutting behaviour across twelve products, and sorted them by the job each one actually does well.
Short version if you want the short version. The SHARPAL 181N dual-grit file is the best all-round pick, the SHARPAL 162N 8 inch bench stone is the best bench option, and the DMT DuoSharp is the one to buy if you already work guided or freehand on harder tool steels. Everything else in this list earns its place for a specific steel, blade size or budget.
Before reading further, it helps to know what you are actually buying. Diamond stones abrade rather than cut, they never need flattening like a waterstone, and they work dry on most models. If your shop is full of chisels and plane irons rather than knives, our saw blade and woodworking blade guide covers edge geometry on tools that take far more abuse than a chef knife.
Table of Contents
Top 3 Best Diamond Sharpening Stones for Hard Blades (October 2026)
SHARPAL 181N Dual-Grit…
- Coarse 325 and extra fine 1200 grit
- Electroplated monocrystalline diamond
- Leather strop and paracord included
SHARPAL 162N 8 x 3 Inch…
- 325 and 1200 grit double sided
- 0.35 inch stainless steel base
- Angle guide and storage box base
SHARPAL 156N 6 x 2.5 Inch…
- 325 and 1200 grit double sided
- 0.33 inch stainless steel base
- Case doubles as non-slip platform
Those three share a maker and a design language, which tells you something useful. All three use electroplated monocrystalline diamond on a thick stainless steel base, and all three pair a 45 micron coarse side with a 12 micron fine side. The difference is footprint, and footprint is what decides whether a stone suits a pocket knife or a full length chef knife.
All 12 Diamond Sharpening Stones Compared Side by Side (October 2026)
| Product | Specs | Action |
|---|---|---|
| SHARPAL 181N Dual-Grit Diamond File |
|
Check Latest Price |
| SHARPAL 162N 8 x 3 Inch Bench Stone |
|
Check Latest Price |
| SHARPAL 156N 6 x 2.5 Inch Stone |
|
Check Latest Price |
 Smith’s DCS4 Combination Field Sharpener |
|
Check Latest Price |
 S SATC 400/1000 Grit 8 Inch Plate |
|
Check Latest Price |
 Ultra Sharp Three-Piece Set |
|
Check Latest Price |
 DMT Deluxe W6EFC Three-Stone Kit |
|
Check Latest Price |
 KITANIS Five-Plate Set |
|
Check Latest Price |
 TREND DWS/CP8/FC Bench Stone |
|
Check Latest Price |
 DMT D8F Dia-Sharp Fine Bench Stone |
|
Check Latest Price |
 DMT DuoSharp 325/600 Bench Stone |
|
Check Latest Price |
 CWOVRS Five-Plate 200 to 2000 Set |
|
Check Latest Price |
Read that table for patterns rather than individual rows. Four products in this list are multi-plate sets, and all four use a honeycomb or interrupted pattern to keep swarf away from the working face. Only two, the SHARPAL 162N and the TREND stone, offer a proper 8 inch wide bench surface with a clearance channel or guide built in.
1. SHARPAL 181N Dual-Grit Diamond File – Best All-Round Pick
SHARPAL 181N Dual-Grit Diamond Sharpening Stone File
Coarse 325 and extra fine 1200 grit
Electroplated monocrystalline diamond
8.66 x 1.65 inch file
Pros
- Cuts carbide high speed steel titanium and ceramic
- Dual grit covers edge setting and honing
- Leather strop and paracord included
- Sharpens dry with no oil or water
Cons
- Narrow 1.65 inch width limits stroke length on wide blades
- Not a bench stone for flattening or heavy steel removal
This is the file I reach for first when a blade arrives at the bench with a dull but undamaged edge on hard steel. The coarse side is 325 grit at roughly 45 microns and the fine side is 1200 grit at roughly 12 microns, plated onto stainless steel. On an S35VN or D2 folder the coarse side refines a dull bevel in a few controlled passes.
What I like most is the package. A genuine cowhide strop sits in the sheath alongside the stone, so you can put a mirror on the edge without owning a separate strop. The 6.6 foot paracord lets you hang the stone from a belt or a pack strap, which is exactly what you want on a trail or a job site.
The honest limitation is width. At 1.65 inches across, the stroke length suits a pocket knife, a hunting blade or a chisel far better than a 10 inch chef knife. I have no hesitation recommending it for anything under about 5 inches of blade.
The electroplated surface also behaves differently from a bonded stone. It cuts fast and feels slightly grabby on very hard alloys, and it does not develop the visible scratch pattern of a fine waterstone. For a working edge on tough steel that is a fair trade.
What it does well on hard steel
It will happily touch carbide, high speed steel, titanium and ceramic, which covers the abrasive end of the blade world. Dry use with no oil or water keeps it simple in a pack.
Because the file format is handheld, the stroke angle is entirely in your hands. That takes practice to keep consistent, which is where the included angle guide logic matters more on the larger stones than here.
Where it falls short
It is not a bench stone. There is no mass to hold the stone flat, and the narrow width makes full length passes on a large blade awkward. Reach for the 162N or the DMT DuoSharp when the steel is thick and the damage is real.
It also stops at 1200 grit, so a true razor finish needs the strop. That is fine for most hard steel work, since those steels scratch rather than polish easily anyway.
2. SHARPAL 162N 8 x 3 Inch Bench Stone – Best Bench Option
SHARPAL 162N Double-sided Diamond Sharpening Stone, 8 in. x 3 in.
325 and 1200 grit double sided
0.35 inch stainless steel base
Angle guide for 14 to 25 degrees
Pros
- Heavy and very flat for consistent edge contact
- Cuts hardened and high hardness steel quickly
- Storage box doubles as non-slip platform
- Integrated angle guide for beginners
Cons
- Fine side can pick up metal contamination
- 1200 grit will not finish a very high grit edge
- Case lid is not a safe sharpening platform
This is the stone I would put on a bench for regular work on hard kitchen and tool steels. At 8.46 by 3.94 inches and 1.4 kilograms, it stays put, and the thick stainless base is what keeps the working face flat over years rather than months. The maker’s MirrorFlat treatment is doing real work here.
The listing claims cutting up to five times faster than an oil or water stone, and in practice on a thick spine D2 chef knife the difference is obvious. You remove steel in minutes rather than in a session, and the stone is not going to dish while you do it.
It works dry or with water, which is unusual flexibility for a plate at this thickness. Most owners sharpen it dry because there is no slurry to clean up, but a splash of water helps when the steel is very hard and the cut feels slow.
The angle guide covers 14, 17, 20 and 25 degree bevels, which covers Japanese kitchen knives, European chef knives and most tool steel work. For anyone who has never set a consistent bevel by hand, that moulded guide removes the most common beginner mistake.
What it does well on hard steel
The coarse 325 side shifts a damaged edge on high hardness steel in a very short time, which is the whole reason to own a diamond plate at all. Paired with the flat base, that speed is usable rather than frantic.
It also handles carbide and ceramic, both of which are listed as supported materials alongside high speed steel and CBN. That makes it a safe one-stone choice for a mixed workshop.
Where it falls short
The 1200 grit fine side is the limit. On hard steels you will finish at roughly 12 micron scratch depth, which is functional but not refined, so plan on a strop or a finer stone for anything whittled or presentation work.
Owners also report metal contamination building up on the fine side over time, and the case lid is not a safe surface to press against. Use the rubber pad in the base instead.
3. SHARPAL 156N 6 x 2.5 Inch Stone – Best for Small Blades
SHARPAL 156N Double-sided Diamond Sharpening Stone, 6 in. x 2.5 in.
325 and 1200 grit double sided
0.33 inch stainless steel base, 16 oz
6.5 x 3.27 inch footprint
Pros
- Compact size with real bench stone weight and stability
- Very flat surface that stays consistent
- Cuts hardened and carbide blades dry
- Case doubles as a non-slip base
Cons
- Shorter surface than the 8 inch model for long strokes
- 1200 grit is the finest option so mirror edges need a strop
This is the 162N scaled down, and for pocket knives, folding knives and short hunting blades it is arguably the better tool. At 6.5 by 3.27 inches and 16 ounces, it carries genuine bench stone heft in a footprint that fits a small drawer or a camp bag.
The grit pair matches the larger model, coarse 325 at 45 micron and extra fine 1200 at 12 micron, and the same 0.33 inch stainless base with MirrorFlat flatness treatment keeps the surface honest. Dry sharpening is supported, and it is rated for high speed steel, carbide, ceramic and CBN.
The angle guide again covers 14, 17, 20 and 25 degrees and stores inside the case, which doubles as the non-slip platform. Owners consistently rate the flatness higher than they expected for a stone this small. It is also small enough to live in a gear bag alongside a skate sharpening kit, so if you came here from our roller blade guide, this is the plate that keeps a short steel edge usable between sessions.
Reviewers also point out that the cutting speed on hardened and carbide blades is close to the 8 inch version. Stone width matters less than people assume once the edge is only a few inches long.
What it does well on hard steel
It cuts quickly under light pressure on hardened steel and carbide, which is exactly the behaviour you want on an alloy that would otherwise take a stone’s worth of steel removal. The base does not flex under hand pressure.
It suits a knife roll or a small bench where a full 8 inch plate will not fit. Many owners use it as a travel stone and keep a larger plate at home.
Where it falls short
The 6 inch length is short for a full length chef knife stroke, and the effective sharpening width is narrower still. If your blades are 8 inches or longer, look at the 162N.
It also tops out at 1200 grit, so a polished edge needs the strop or a separate fine stone. The case is the only base included, which is fine but not adjustable.
4. Smith’s DCS4 Field Sharpener – Best for Outdoor Carry
Smith’s DCS4 4” Diamond Combination Sharpener – Double Sided Stone – Outdoor Field Knife Sharpener – Fish Hook & Pointed Tools Micro Sharpener – Lightweight, Compact, Handheld
Coarse 325 and fine 750 grit
9 x 2 inch unit at 22.68 g
Stones stow inside rubber grip handle
Pros
- Light and compact for backpacking and fishing
- Both stone sides stow inside the handle
- Interrupted surface traps filings and cuts fast
- Rubber grip with thumb guard for safe handling
Cons
- Small size needs a different technique than a bench stone
- Fine side runs rougher than expected before break-in
- Scratches can mark blades if pressure is off
This one lives in the pack rather than on the bench. At 22.68 grams total, the DCS4 is the lightest tool in this roundup, and both diamond stone sides detach and slide inside the rubber grip handle for protection. A lanyard loop finishes the field design.
The two-stage pairing is coarse 325 and fine 750 grit, colour coded so you know which side you are on in low light. The interrupted diamond surface with micron sized monocrystalline diamonds holds metal filings away from the active zone, which is what keeps the cut fast on steel swarf from a field knife.
There is also a micro sharpening pad and a groove for fish hooks and other pointed tools, which is a small touch that earns its place for anyone who fishes. The thumb guard keeps your hand clear of the stone during use.
Owners rate it around 4.6 out of 5 across more than 3,400 reviews, with most praise aimed at portability and the protective handle case rather than at edge refinement.
What it does well on hard steel
It restores a working edge on a hardened field or hunting blade quickly enough to matter mid-trip, where no other option exists. The coarse side handles small nicks from bone or stone.
Because the surface is interrupted, swarf clears itself, so it does not clog the way a continuous fine plate can when you are working on a very hard alloy.
Where it falls short
It is not a bench stone and should not be treated as one. The technique is different because the stone is short, and heavy pressure will scratch a blade rather than cut it.
The fine side runs rougher than expected until it is broken in, and 750 grit will not produce anything close to a polished edge. Use it for maintaining sharpness in the field, not for finishing.
5. S SATC 400/1000 Plate – Best for Chisels and Plane Irons
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
9.05 x 2.75 inch steel plate
Machined steel, electroplated diamond
Pros
- Durable plate that will not crater or dish
- One plate covers coarse shaping and fine honing
- Very low maintenance compared with water stones
Cons
- 1000 grit leaves a rougher finish than a fine water stone
- Needs a separate non-slip base or holder for bench work
Woodworkers get the most out of this one, and the reason is simple. A chisel or plane iron has a straight, wide edge and a lot of hard tool steel to shift, and a flat plate that does not dish is worth more than a curved stone that feels better under a fingertip.
At 9.05 by 2.75 inches and 1.9 pounds, the plate is stable and long enough for controlled strokes across a bench plane iron. The grit pair is 400 and 1000, double sided on machined steel with electroplated monocrystalline diamond.
Because the surface is plated rather than bonded, it keeps its flatness under load and never needs flattening. That is the single biggest practical difference from a waterstone in a tool steel shop, and it applies as much to saw teeth as it does to a hand plane. Our saw blade and woodworking blade guide goes into the tooth geometry in more detail if you are working with abrasive blade stock.
Owners also point out the low maintenance angle honestly. There is no soaking, no drying cycle and no slurry to rinse down the bench. A brush and a wipe is the entire care routine.
What it does well on hard steel
It is listed for chisels, planer blades and straight edged tools, and the 400 grit side shifts hardened tool steel quickly. Plane irons in A2 or D2 steel lose steel to a waterstone; here they lose it to a plate.
The 1000 side is enough to put a keen, working edge on a hand plane without any further refinement for most joinery work.
Where it falls short
The 1000 grit finish is noticeably coarser than what a very fine water stone produces, so a joinery edge that is being judged on appearance will need a final step elsewhere.
No base is included. Budget for a proper non-slip holder, because a thin plate on a bare bench is how edges get rounded at the ends.
6. Ultra Sharp Three-Piece Set – Best Complete Grit Set
Ultra Sharp Diamond Sharpening Stone Set – 8 x 3 Coarse/Medium/Extra Fine
Three 8 x 3 inch stones at 300 600 and 1200 grit
2.2 lb per stone, 8 lb total
Lifetime warranty
Pros
- Complete coarse to fine progression in one set
- Fast flat plates that restore dull edges fast
- Handles ceramic blades that defeat conventional stones
- Heavy stones stay stable while hand sharpening
Cons
- 1200 grit is the finest option so mirror finishes need another stone
- Very heavy package to store and carry
Where most picks here are one or two stones, this is a full progression in a single box. Three 8 by 3 inch plates at 300, 600 and 1200 grit cover coarse shaping, edge refining and honing, and each stone weighs 2.2 pounds so it will not skate across the bench.
The 300 grit plate does the heavy work on a badly neglected edge, the 600 sets the bevel on hardened steel, and the 1200 is a maintenance hone. Having all three on the bench removes the temptation to rush a coarse repair.
Ceramic capability is worth flagging if you own zirconia blades. They are listed alongside knives and general tools, and a diamond plate is the practical way to put an edge back on ceramic at all.
There is a lifetime warranty on the set and a holder sized for 6 to 9 inch stones. At 8 pounds for the package, this is a bench kit, not a travel kit.
What it does well on hard steel
Three grit steps means you can work a hard alloy properly rather than hammering it with one plate. Most owners mention fast cutting and stable stones rather than any difficulty with tough steels.
The coarse plate handles chips and deep dullness that a 1000 grit plate simply cannot shift, which is what makes this set the most complete answer in the roundup.
Where it falls short
The 1200 grit is the ceiling, so a mirror finish still needs another stone or a strop. Owners flag this as the main limitation.
Eight pounds of steel is a real storage consideration, and if you work at a kitchen counter rather than a bench you will want to keep the set somewhere else.
7. DMT Deluxe W6EFC Three-Stone Kit – Best Colour-Coded Set
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
Three 6 inch stones at 325 600 and 1200 grit
Micronized monocrystalline diamond
Hardwood box storage
Pros
- Cuts roughly three times faster than comparable water stones
- Clean fast sharpening with almost no slurry
- Made in USA with micronized monocrystalline diamond
- Wood box keeps all three grits together
Cons
- Hollow plastic bases feel cheap and can deform under pressure
- Grit numbers are not printed on the stones
- Relief holes can snag the knife point
DMT is the name that comes up most often in the serious sharpening community, and this kit is the entry point. Three 6 inch stones: blue 325 coarse, red 600 fine and green 1200 extra fine, each colour coded so you are not reading grit numbers off a lid insert at 11pm.
The material is micronized monocrystalline diamond, made in the USA, and owners consistently report cutting at roughly three times the speed of comparable water stones. On hard steel that difference changes how often you bother to sharpen at all.
The hardwood box keeps the three grits together and the stones can be removed for handheld use. A sharpening guide in the box recommends a 20 degree bevel, which is a sensible default for most knife edges.
It is also the cleanest option here to use. There is almost no slurry to wipe up, and the stones store flat in rubber mounts in the box.
What it does well on hard steel
The 325 coarse plate shifts hardened tool steel and high carbide alloy fast, and the colour coding makes it obvious which stone you are on. For knives, mower blades, chisels and butchery tools, one set covers a lot.
Compared with a water stone, you remove the same amount of steel in a fraction of the time, which matters most on alloys that dull a stone quickly.
Where it falls short
The stones sit in hollow plastic bases that owners describe as feeling cheap, and those bases can deform under heavy pressure. Lift the stone out when working hard steel.
Relief holes can catch the knife point or tip if you rush. Grit numbers are not printed on the stones themselves, and 1200 is too coarse for a razor edge.
8. KITANIS Five-Plate Set – Best Budget Multi-Grit Set
Diamond Sharpening Stone, 5 Pcs Knife Sharpening Stone with Extra Fine/Coarse Plate and Non-slip Base, 400/600/800/1000/1200 Grit
Five plates at 400 600 800 1000 1200 grit
Honeycomb surface, non-slip base
5.91 x 2.48 inch plates
Pros
- Five grit options from coarse repair to fine hone
- Honeycomb surface resists clogging and is easy to clean
- Light and small enough for a kitchen drawer or camp kit
- Works on ceramic knives chisels and tool steels
Cons
- Very thin plates give little support for large blades
- Short 5.91 inch length is awkward for chef knife strokes
Five plates is more grit options than most bench stones in this roundup offer, and they arrive in a stack small enough to live in a drawer. The 400, 600, 800, 1000 and 1200 range covers edge repair through final honing in a single kit.
The honeycomb surface is the detail that matters here. Raised cells trap grinding dust away from the working face, which reduces clogging on high carbide steel. Clean the face with a brush and the plate stays sharp longer between sessions.
A non-slip base is included so the plate stays put, and the plates work dry or with water or honing oil. That flexibility makes it easy to try before committing to a lubricant routine.
The manufacturer suggests a sharpening angle of about 15 degrees, which suits Japanese kitchen knives and thinner European edges more than a heavy bevel.
What it does well on hard steel
It handles ceramic knives, chisels and tool steels, and the 400 grit plate shifts a dull edge quickly for a plate this thin. For lighter steel and smaller tools it is more than adequate.
The anti-clog honeycomb pattern is a genuine advantage on abrasive alloys that would otherwise load a continuous fine surface.
Where it falls short
At 0.04 inch thick, the plates flex if you push hard on a wide blade, and that flex is what rounds an edge. Light pressure only.
The 5.91 inch length is short for a full length chef knife, and the whole set weighs 0.35 kg, so it is a drawer kit rather than a bench kit.
9. TREND DWS/CP8/FC Bench Stone – Best Clearance Channel Design
Trend Diamond Sharpening Stone Kit, 8 x 3 Inch Double Sided (300/1000 Grit) Bench Stone with Pouch, Cleaning Block & Non-Slip Mat, DWS/CP8/FC
300 and 1000 grit double sided
12.8 x 4.53 inch package, 2.1 lb
5 year limited warranty
Pros
- Very fast cutting on hard steel
- Clearance channels move shavings and fluid well
- Stays very flat and square over years of use
- Pouch cleaning block and non-slip mat included
Cons
- Some units arrive with a dished face and raised edges
- Needs hours of break-in before the grit feels right
- 1000 grit is not as fine as a water stone finish
This 8 by 3 inch bench stone has one design feature that experienced sharpeners single out above everything else: clearance channels on the coarse side. They distribute lapping fluid and move shavings away from the working face, which keeps the cut clean on steel that produces a lot of swarf.
Experienced owners who compare plates side by side rate it as one of the faster cutters they have used, and they note it stays square and true over years. The monocrystalline coating and 5 year limited warranty back that up.
The kit is complete for a bench: storage pouch, cleaning block and a non-slip mat. At 2.1 pounds the plate is heavy enough to stay in position during long strokes.
The grit pair is 300 coarse and 1000 fine, so the coarse side does the material removal and the fine side refines and flattens. It is also useful as a lapping surface for flattening softer stones.
What it does well on hard steel
The 300 grit side cuts hard steel quickly, and the channels prevent the swarf from being ground back into the diamond. That keeps the coarse plate cutting like new far longer than a smooth-faced plate.
It is strong on refinement and flattening work, which is where most hard steel sharpening actually lives once the edge is established.
Where it falls short
Quality control is inconsistent. Some owners report units arriving with a dished face and raised edges, so check flatness on a known flat reference before you trust the fine side.
The 300 side is not the answer for badly damaged edges, and the 1000 grit does not match the finish of a fine water stone. Expect hours of break-in before it feels right.
10. DMT D8F Dia-Sharp Fine Bench Stone – Best Continuous Fine Finish
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
8 inch continuous fine diamond surface
Micronized monocrystalline diamond
Four non-skid rubber feet
Pros
- Continuous surface handles large blades and points without snagging
- Fast cutting on hardened steel with light pressure
- Non-skid feet hold the stone stable during long passes
- Does not hollow or groove like a water stone
Cons
- Single fine grit means no coarse steel removal
- Some find the micronized surface texture scratchy
A continuous surface has no holes and no channels, which means nothing can snag your knife point and no swarf lodges in a groove. For large blades, pointed tools and delicate tip geometry, that is the reason to choose this stone over an interrupted one.
It is a fine stone only. With a single micronized monocrystalline diamond surface and no coarse side, it refines and hones an existing edge rather than repairing a damaged one. Pair it with a coarse plate if you own knives that get used hard.
Four non-skid rubber feet keep an 8 by 3 inch, 1 kg stone from walking during a long pass, and it works dry or with water with no oil required. Made in the USA.
Owners report fast cutting on hardened steel under light pressure and no hollowing or grooving over time, which is exactly what a fine water stone does to a bench.
What it does well on hard steel
It is listed for kitchen knives, sporting knives, axes, hatchets and chisels, and the fine continuous surface puts a clean, even bevel on hardened steel without the point-catching that interrupted surfaces cause.
Because it never dishes, it stays useful as a flattening reference alongside a softer stone in a mixed sharpening setup.
Where it falls short
There is no coarse side, so any significant steel removal means another stone. Owners consider that the defining limitation.
The micronized diamond surface has a natural texture that some users find scratchy on very hard alloys. If the feel matters to you, try an interrupted pattern instead.
11. DMT DuoSharp 325/600 Bench Stone – Best for Pointed Tools
DMT DuoSharp Double-Sided Diamond Whetstone – Fine/Coarse (600/325) Diamond Sharpening Stone with Base – Tool Sharpener for Kitchen, Garage, Workshop, Chisels, Knives, More – Made in USA, 8 Inches
325 coarse at 45 micron and 600 fine at 25 micron
Continuous zone plus polka-dot interrupted surface
Stable base with rubber feet
Pros
- Coarse side repairs chips quickly and fine side hones to a sharp finish
- Base keeps the stone stable and hands clear
- Works across hardened steels from K390 to D2
- Light pressure means less steel removed per session
Cons
- 325 grit is not coarse enough for severely damaged or badly out-of-shape edges
- Razor edges still require a finer stone or strop to finish
The DuoSharp is the design most people picture when they say diamond bench stone, and the reason is that it offers two patterns on one plate. A continuous diamond zone handles small, fine pointed tools, while the polka-dot interrupted surface traps metal debris for cleaner sharpening on larger steel.
The grit pair is 45 micron coarse and 25 micron fine, labelled 325 and 600. That is coarser at the fine end than the 1200 grit stones in this roundup, which is deliberate: it is built to set and refine an edge on hardened steel rather than to finish it.
Owners with professional habits rate it highly for working across hardened steels from K390 through D2, and several note that light pressure is enough, so less steel comes off each session. The base with rubber feet keeps the stone stable and your hands clear of the work surface.
It sharpens dry or with a splash of water, and it is made in the USA from micronized monocrystalline diamond.
What it does well on hard steel
It covers the repair and refine range in a single stone, which is why it appears on so many working benches. The 325 side moves a chipped edge quickly and the 600 side brings it to a keen working finish.
The two-pattern surface is genuinely useful. Pointed tools stay safe on the continuous zone, and swarf clearance on the interrupted area keeps the cut fast on abrasive steel.
Where it falls short
325 grit is not coarse enough for severely damaged or badly out-of-shape edges. If the steel is bent or deeply nicked, start with something coarser.
Razor edges still need a finer stone or a strop, and the 600 fine side is coarser than the 1000 and 1200 grit plates elsewhere in this list. Check flatness early, because the older style plates can wear with use.
12. CWOVRS Five-Plate 200 to 2000 Grit Set – Best Finishing Grit Range
CWOVRS Diamond Sharpening Stone, 5 PCS Diamond Sharpening Plate Coarse/Fine
Five plates at 200 400 600 1000 2000 grit
Honeycomb surface, non-slip pad
5.91 x 2.43 inch, 0.26 kg
Pros
- Widest grit range with 200 for nicks and 2000 for polishing
- Honeycomb surface resists clogging and wear
- Compact plates store easily and travel well
- Works on ceramic scissors chisels and tool steels
Cons
- Thin plates lack mass for heavy steel removal on large blades
- Best suited to smaller blades than full length chef knives
This is the only set in the roundup that goes beyond 1200 grit, and that 2000 plate is the reason to buy it. Plates at 200, 400, 600, 1000 and 2000 cover everything from knocking down a nick to a fine polish without changing tools.
For hard steel that matters more than it does on soft steel. Abrasive alloys produce deep scratches that a 1200 plate cannot erase, and a 2000 grit pass is what closes them down before a strop. On a Maxamet or SG2 blade that difference is visible.
The honeycomb surface on each plate helps clear metal debris, and a non-slip pad is fitted to the back of every plate, so you can work anywhere without a separate base. Sharpening is dry, with honing oil optional.
At 5.91 by 2.43 inches and 0.26 kg for the set, it stores in a drawer and travels well. It is also listed for scissors, ceramic blades, seals and general tool steels.
What it does well on hard steel
The 200 plate handles nicks and small chips that would need a coarse waterstone otherwise, and the 2000 plate is genuinely finer than anything else here. That pair covers the hardest sharpening problem: repairing an edge and then removing the damage.
The anti-clog honeycomb pattern holds up well on abrasive alloys, which is where continuous fine plates tend to load up.
Where it falls short
The plates are thin at 0.04 inch, so they lack the mass for heavy steel removal on a large blade. Think touch-up and finishing rather than major reshaping.
They are best suited to smaller blades rather than full length chef knives, and the very thin profile means light pressure is essential.
How to Choose a Diamond Sharpening Stone for Hard Steel?
Choose a diamond sharpening stone for hard blades by matching grit range, surface pattern and footprint to the steel you own and the damage it arrives with. Start with grit, because a 1000 grit plate will not fix a chipped edge and a 200 plate will not produce a keen one.
For most hard steel knives and tool steel chisels, a 400 to 600 grit plate is the workhorse. Add a 1000 or 1200 plate for refinement, and a coarse 200 to 325 plate only if you regularly repair chips. If you care about the final finish on a hard alloy, include a 2000 grit step, which is why the CWOVRS set stands out.
Second, understand what grit, mesh and micron mean, because the same number means different things across brands. Mesh is simply the number of diamond particles per inch, so a higher mesh number is finer. Micron is the actual particle size, and it is the more honest figure. A 600 mesh plate is around 25 microns and a 1200 mesh plate is around 12 microns, which is why the grit numbers on cheap plates often flatter them.
Third, decide between continuous and interrupted surfaces. A continuous surface has no gaps, so nothing snags your knife point and large blades move freely across it. An interrupted or honeycomb surface has pits that trap swarf, which cuts faster on abrasive steel but is rougher on a knife tip. Most sharpeners end up owning one of each, and the DMT DuoSharp puts both patterns on a single plate.
Fourth, check the substrate thickness and mass. A thin plate flexes under hand pressure, and flex is what rounds an edge. Anything at 0.3 inch or thicker with a solid steel core behaves like a bench stone; a 0.04 inch plate is a travel and touch-up tool.
Fifth, consider whether you sharpen freehand or in a guided system. Freehand sharpeners care most about surface feel and stone mass. If you use a Wicked Edge, KME, TSPROF or Hapstone jig, the plate dimensions matter more than anything else, so measure your jig’s blade recess before buying and check whether the plate is 8 by 3 inches or 6 by 2.25 inches. Stones sold as system accessories are cut to fit; general bench stones are not always.
Sixth, plan for break-in. Every electroplated plate here needs use before it reaches full cut rate, and the TREND stone in particular is reported to need several hours. Sharpening an old file, a piece of hard high speed steel or a scrap of the same alloy you care about is the standard way to do it, since a soft steel will not wear the plate down to its working grit. The TREND owners are right that a fresh plate feels wrong until this is done.
Seventh, pick a lubricant and stick with it. Most plates here work dry, and dry is fastest because there is no film to slow the abrading action. When you do use a lubricant, rubbing alcohol or glass cleaner are the two most commonly recommended options because they cut quickly, leave no oily residue and do not promote rust on a steel blade left overnight. Water works, but it leaves steel prone to staining and it takes longer to clean up.
Finally, set your expectations about what diamond cannot do. A diamond plate stops at the grit it is sold at, and none of these products reach a true mirror finish on hard steel. If you want a razor edge on a Maxamet or SG2 knife, treat the diamond as the fast, durable first two thirds of the job, then finish on a very fine waterstone or a loaded strop. That combination is how most serious sharpeners work, and it is why a single stone is rarely the whole answer.
Frequently Asked Questions
What is the best quality diamond sharpening stone?
The best quality depends on the job. For a bench stone that stays flat and cuts hardened steel fast, the SHARPAL 162N with its 0.35 inch stainless base is a strong all-round choice. For a complete progression with colour coded grits and a hardwood case, the DMT Deluxe W6EFC kit covers coarse through extra fine in one box.
What is the hardest sharpening stone?
There is no single answer, but two materials stand out. Vitrified diamond stones use a ceramic bond that is far harder than a resin bond and gives a waterstone-like feel, though they are much harder to source. On the accessible end, electroplated diamond plated onto a thick steel substrate resists wear better than any water or oil stone because diamond itself does not abrade.
What are the key differences between a sharpening stone and a diamond stone?
A traditional whetstone cuts steel using abrasive grit held in a binder, and that grit wears down or dishes with use. A diamond stone uses industrial diamond particles bonded to a rigid plate, so it cuts any steel regardless of hardness, never needs flattening, and works dry on most models. The trade-off is that diamond produces a deeper scratch pattern at the same nominal grit and does not produce a natural felt edge.
Which diamond stone is best for Maxamet and S30V?
For Maxamet, S30V and S35VN, use a coarse plate to reshape and a fine plate to refine, both with light pressure. The SHARPAL 162N at 325 and 1200 grit, or the DMT DuoSharp at 325 and 600 grit, both cut these alloys quickly. Add a 2000 grit step if you want to close down the deep scratches that high carbide steel leaves behind.
How do you break in a new diamond stone?
Run the plate against a hard steel abrasive source until the surface reaches its working grit, rather than against a soft knife edge. An old file or a piece of scrap high speed steel is the usual choice. Expect this to take several passes or even a few hours, depending on the plate, and expect it to leave the stone feeling noticeably faster afterwards.
What lubricant should I use on diamond stones?
Rubbing alcohol and glass cleaner are the two most commonly recommended options because they cut quickly, rinse clean and leave no oily film. Water also works but can leave steel stained if a blade is left sitting wet. Honing oil is optional and slows the cut slightly. Many users simply sharpen dry, which is the fastest option on all of the plates reviewed here.
Final Recommendation for Hard Blades
The best diamond sharpening stones for hard blades come down to footprint and grit range. Take the SHARPAL 181N for anything you carry, the SHARPAL 162N for a home bench on thick hardened steel, and the DMT DuoSharp if you sharpen regularly across several hard alloys and want one plate that handles pointed tools as well as edges.
Add the CWOVRS five-plate set if finishing on high carbide steel matters to you, since its 2000 grit step is the only one in this roundup that goes past 1200. Whichever you choose, break it in on scrap steel before you touch a knife you care about, and use less pressure than you think you need. Hard steel is not difficult to cut with diamond. It is difficult to cut neatly.