HP HSS Thin Knife Set — 18-1/8 x 1-1/8 x 5/32, 3-Knife

The TN640HP is a 18-1/8″ × 1-1/8″ × 5/32″ HP HSS thin knife set for jointers and planers with 18-1/8-inch cutting width. Thin knife sets are precision-ground to the exact machine knife length, matching the cutterhead slot dimension of specific machine models with 18-1/8-inch capacity. The 1-1/8 knife width (height) and 5/32 thickness are the head slot specifications — confirm both dimensions match the installed cutterhead before ordering. Sold as a set of matched knives for the full head complement required by the machine. HP high-speed steel is the standard knife material for jointer and planer applications — reliable edge quality and resharpened on standard surface grinding equipment. After installation, set knives to the correct height above the cutterhead using a setting jig or dial indicator for consistent, flat surface results. Thin knife geometry suits jointer and thicknesser heads designed for this knife section; do not substitute for corrugated-back or smooth-back bar-length stock without confirming head compatibility.