DMT W250CXNB DuoSharp Double: problems, parts and running costs

Checked: 2026-10-23

Summary

The DMT W250CXNB is a 10 x 4 inch double-sided diamond bench stone with a coarse (45 micron / 325 mesh) face and an extra-coarse (60 micron / 220 mesh) face, sold without a base. It sets bevels and repairs damaged edges fast but does not finish an edge, needs drying after wet use to avoid rust, and has no recurring consumable cost; it is a good buy near $135 and a poor one above $180.

Common problems and fixes

No finished edge — the coarse/extra-coarse pair sets bevels and repairs damaged blades but will not leave a great finished edge; a fine/extra-fine stone is needed to finish. [1]
No base in the box — “NB” means no base; KnifeCenter tells buyers to add the DuoBase accessory (part DMTB8250) at purchase, and one seller’s “non-skid rubber base” wording conflicts with two no-base listings for the same part number. [1][3][4]
Aggressive extra-coarse face — DMT positions the 60 micron / 220 mesh black face for heavy metal removal on damaged tools and outdoor tools such as axes and lawn-mower blades; it is not a finishing surface. [3][7][8]
Break-in feel — the diamond surface can seem aggressive at first and smooths after initial sharpening, with no impact on long-term performance. [8]
Warranty excludes wear and misuse — DMT replaces units with defects in materials or workmanship regardless of age, but normal wear, industrial use, abuse, misuse or neglect is not covered. [8]

Parts and consumables

No replaceable parts or consumables reported.

Yearly running cost

No recurring consumable cost: the diamond surface needs no oil and is cleaned with water, a mild abrasive cleanser and a nylon brush, then stored dry. The only costs are one-time — a finer stone to finish an edge and the optional DuoBase (part DMTB8250). No electricity or subscription applies. Not enough data for a dollar figure. [1][3][7][8]

When it is a good buy

At $135 or less — strong value for the coarse side of a bench setup, given the 10 x 4 in (250 x 100 mm) working surface and roughly 87% more surface than the 8-inch model. [1][3][4]
$136-$180 — fair to good; still below the base-equipped W250CX-WB at $143.85 sale and the $179.99 list. [3][7][11]
Above $180 (up to the $185.99 SMKW listing) — poor value, since two US sellers already undercut it. [1][2][3]
Above $200 — not defensible on the pages read; the $249.00 Canadian listing is a different market. [4]

Named alternatives: the base-equipped W250CX-WB for bench stability at $143.85 sale [3]; the 8-inch W8CXNB at $95.75 sale or WM8CX at $74.25 sale for smaller budgets [3]; and a fine/extra-fine DuoSharp stone to finish edges [1].