DMT D8F Dia-Sharp Bench Stone: problems, parts and running costs
Checked: 2026-10-20
Summary
The D8F is an 8-inch single-grit fine (25 micron / 600 mesh) diamond bench stone; the thing that goes wrong is usually a limitation, not a defect — it cannot repair a chipped edge because it is one grit only, and DMT’s 20-degree sharpening guidance does not suit thin Japanese knives. There is no oil, compound, electricity or subscription, so the running cost is the plate itself, replaced on the multi-year horizon DMT describes. It is a good buy at $82.99 direct from DMT if you already own a coarser plate; at about $105 from Country Knives a two-grit plate is the better single purchase.
Common problems and fixes
- One grit only, so a chipped edge cannot be repaired — the D8F is fine 25 micron / 600 mesh only; a chipped or badly damaged edge needs a coarser plate, which is a separate purchase, and Gyuto Club makes this the main argument against the D8F as a single purchase. Not a defect; the fix is owning a coarse plate alongside it. [3]
- DMT’s 20-degree angle advice does not suit thin Japanese knives — DMT’s FAQ recommends 20 degrees per side and says a constant angle matters more than the exact angle; Shun publishes 16 degrees per side and most VG10 gyuto edges sit near 15, so running Japanese knives on this plate at 20 degrees thickens the edge rather than maintaining it. Set the angle yourself instead of following the FAQ. [3]
- Aggressive break-in removes more metal than expected — DMT’s own answer describes the surface as aggressive until it is broken in, so the first few sharpenings can remove more metal than a buyer expects; the surface smooths after break-in with no impact on long-term performance. [3]
- The diamond surface wears out after several years — DMT says its sharpeners last several years but not forever, and there is no way to re-dress or re-plate the surface, so a worn plate is replaced rather than repaired. [3]
- Weight and body material are unpublished — DMT does not publish the plate’s weight or body material, and the only anti-slip provision is the rubber feet, so how the stone behaves on a wet counter without a holder is unconfirmed. [1][3]
- Warranty terms are unverified — DMT publishes a warranty page, but it returned no readable warranty terms when fetched, and neither DMT’s product page nor the Country Knives listing states a warranty period for this stone; confirm coverage with the seller. [11][1][2]
Parts and consumables
No replaceable parts or consumables reported.
Yearly running cost
No per-year figure can be computed from the sources. The stone needs no oil, no compound, no water treatment and no electricity, and the only consumable is the plate itself, which DMT describes as lasting several years rather than forever [3]. There is no subscription or service charge. The practical cost until the diamond surface wears out is the replacement price of $82.99 at DMT direct or $105.00 at Country Knives [1][2].
When it is a good buy
DMT direct listed the D8F at $82.99 (2026-10) and Country Knives listed the same stone as DMD8F at $105.00 (2026-10) [1][2].
- At $82.99 direct from DMT it is a defensible buy for someone who already has a coarse plate and wants one flat, continuous fine surface for daily kitchen-knife maintenance [1].
- At about $105 from Country Knives the value narrows, because at that money a two-grit plate covers both edge repair and routine sharpening; the Gyuto Club review calls the two-grit DuoSharp the better single purchase and notes the D8F costs about the same as a double-sided SHARPAL for half the grits [3].
- Above roughly $105 the D8F is hard to justify as a single purchase, because the same money buys two grits from the same maker [2][3].
Named alternatives:
- DMT DuoSharp two-grit plates — the W250CXNB at $228.00 and the W250FC DuoSharp system at $260.00 at Country Knives; the better choice when one plate must do both edge repair and routine sharpening [2].
- DMT D8 C/X double-sided fine/coarse plate — a two-grit sibling; the better choice when you want repair and honing on one plate [10].