Why diamond, not a water stone
Diamond is harder than every carbide in every knife steel, so a diamond plate cuts modern wear-resistant alloys at the same rate it cuts plain stainless. A water stone’s abrasive is softer than some of those carbides, which is why a stone that flies through a kitchen knife feels like polishing glass on a high-carbide folder blade.
The second reason is flatness. Water stones dish — they hollow out in the middle where you work — and a dished stone puts a convex bevel on a short blade fast. Diamond plates never dish and never need flattening, which removes the maintenance step most people skip. DMT’s interrupted “polka-dot” surface also clears steel swarf instead of loading up with it, so it keeps cutting through a long session. The full comparison is on diamond stone vs whetstone.
Which grits you actually need
Two, and then stop. A coarse platearound 325 mesh (45 µm) resets a damaged or badly rounded bevel. A fine plateat 600 mesh (25 µm) is where a working pocket knife actually lives — it leaves a toothy edge that bites rope, cardboard and plastic strapping better than a polished one does. The DMT DuoSharp gives you both faces in one plate; the SHARPAL 162N goes further to Extra Fine 1200 (12 µm) if you want a cleaner finish.
Resist the urge to chase 6000 grit on a folder. A mirror polish looks impressive and slices paper beautifully, and on fibrous material it under-performs the slight tooth a 600-grit edge keeps. If you want the polish anyway, finish on a strop rather than buying another stone — best strops and how to strop a knife cover that. The grit map in general is the whetstone grit guide.
Two related questions come up constantly here, and both have a page of their own: is a 1000 grit whetstone enough(for an undamaged edge, largely yes) and how to identify an unmarked stone’s grit, which is the one to read if the plate in your drawer came without a label. Our bench-plate pick also has a review of its own — the DMT DuoSharp review.
Freehand or guided
Be honest about this one, because it decides which half of the page you should read. On a 200 mm chef’s knife you can feel the blade’s plane against the stone and hold it. On a 75 mm folder there is far less blade to feel, the handle is in the way, and most people’s first attempts round the bevel over.
- Guided (the Lansky)if you want repeatable results from the first session. You clamp the blade, pick an angle hole, and the rod holds it for you. The compromise: fixed holes cannot match a bevel that sits between angles, and small hones make long blades slow — irrelevant on a folder.
- Freehand on a plate (DMT or SHARPAL) if you want a skill that works on every knife you will ever own. Use the angle guide that comes with the SHARPAL 162N, or a marker on the bevel to check you are hitting it, and keep the strokes slow.
The angles to aim for are in the sharpening angle guide. For a folder, 20° per side is the safe default and 25° is right for a hard-use blade you pry and scrape with; 15° is a kitchen number and it will chip on a work knife.
Serrated folders, and the one tool that handles them
A large share of pocket knives are partly serrated, and no flat stone sharpens that section — a serrated edge has to be done one scallop at a time with a tapered rod that fits itself to each gullet, working only the bevelled side. The Lansky folding diamond rod is the cheap, pocketable answer and the DMT Diafold is the specialist one; Lansky publishes no mesh or micron grade for its rod, which is the one thing we hold against it.
The whole method, including why you never touch the flat back of a serrated edge, is in how to sharpen a serrated knife, and the ranked field is best serrated knife sharpeners.
What not to use on a pocket knife
Three things, briefly. A carbide pull-throughscrapes metal away in a tearing action and leaves a rough edge that fails quickly — it will make a blunt folder cut again and it costs you blade life every time. A bench grinder or belt sander run dry will overheat a thin edge and destroy the heat treatment in the top fraction of a millimetre, which is not recoverable. And a grooved steel honing rod does nothing useful here: it is designed to straighten soft kitchen steel, and a hard folder edge does not roll in the way that tool exists to fix.
One stone and one angle, held consistently, beats every gadget. If you are starting from nothing and want the cheapest honest kit, read best whetstones for beginners — and if your folder is already dull enough that you are impatient, the coarse side is the answer, not more pressure.
