Drilling with Forstner bits to achieve a flat-bottomed hole or to start a deep turning project such as a large vase or vessel can be nearly impossible with a standard-length bit. To solve this, weve developed a heavy-duty steel extension that securely holds any 3/8-inch shank Forstner bit in its precision-machined collet.

This Forstner bit extension adds an extra 5-5/8 inches of reach, allowing you to bore deeper into your projects. Its ideal for creating large-diameter starter holes or drilling just a bit farther than your standard bit length allows. The extension can be used with Forstner bits on drill presses, lathes equipped with a drill chuck (chuck not included), or with a power drill.

Woodturners often use this extension for boring starter holes in larger vessels, while its equally useful for projects like salt shakers, pepper mills, and turned mugs. Contractors also rely on it for drilling deep holes when running cables or wires, as well as for joining larger timbers.

The extension is crafted from solid, heavy-duty machined steel and designed specifically for Forstner bits. The collet inside diameter is 3/8 inch, with tight tolerances to fit bits of 3/8 inch or slightly smaller shank sizes. Please note that some manufacturers label their bits as 3/8 inch when the actual size may vary slightlyverify your shank size for a proper fit before use.

The collet outside diameter measures 25/32 inch (excluding the set screws). Because some bit shanks vary, the set screws may protrude slightly. The minimum hole diameter this extension can drill is 13/16 inch.