Drill America Cobalt Aircraft Extension Drill Bit #3 12in 2130

Drill America #3 Cobalt Extension Bit

The Drill America #3 cobalt aircraft extension drill bit is built for deep-hole drilling in tough alloys and stainless steel. Its 12-inch overall length reaches areas that standard bits cannot, while the heavy-duty split point reduces walking and starts cleanly on hard surfaces. Cobalt steel construction resists heat and wear during extended use.

Upgrading from standard jobber-length bits

This bit replaces shorter high-speed steel drills when extra reach is required in aircraft maintenance or structural fabrication. The jump is worth it when hole depth exceeds the flute length of a conventional bit or when material hardness causes rapid dulling of non-cobalt tools. It is not suited for handheld drilling in thin sheet metal where a shorter, more rigid bit provides better control.