Original DeWalt 577199-00 — replacement nut for Black & Decker / DeWalt Workmate vice assemblies. This injection-moulded white nut has a left‑hand thread and is the threaded fastener that locks the jaw spindle in place on the vice/jaws; it mates with the M8 bolts used in the jaw assembly (bolt shown as M8 × 38 mm in the parts diagram). Fits Workmate models WM550, WM747, WM750, WM800, WM825 and WM835. Sold individually and ready to swap into the vice spindle—simply remove the spindle/bolt and replace the nut to restore proper jaw clamping.

Note: manufacturers’ exploded parts lists identify this as a white, left‑hand threaded nut used on the vice (part 577199-00) and show the associated bolts as M8 × 38 mm, but I could not find a published overall outer diameter or thread‑pitch spec for the nut beyond the left‑hand/M8 association in the parts diagram.