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Silver cobalt steel aircraft extension drill bit 21/64in diameter 12in long split point tip

Drill America

Drill America 21/64in x 12in Cobalt Aircraft Extension Drill Bit pneumatic accessory

SKU CH-7VZQ-6ZV8G

Cobalt aircraft extension drill bit with a 21/64 inch diameter, 12 inch overall length and heavy-duty split point for deep drilling

  • Product typeDrill Accessories
  • 21/64 inch size matches precise drilling needs
  • Cobalt steel construction resists heat during extended use
  • 12 inch overall length reaches confined work areas
  • Split point design starts holes without wandering

21/64-inch Cobalt Aircraft Extension Drill Bit

The Drill America cobalt aircraft extension drill bit measures 12 inches overall with a flute length of 3-5/16 inches. Its heavy-duty split point design reduces walking on hard surfaces. The cobalt steel construction resists heat and wear during demanding drilling tasks.

Suited for deep-hole drilling in tough alloys

This bit serves machinists and maintenance crews boring deep holes in stainless steel, titanium and other hard metals. The 12-inch reach fits aircraft-structure work and similar confined spaces. Builders needing a shorter flute length, a different diameter or a lower-cost general-purpose bit should consider other options.

How it compares

Measured against everything we stock in Bits, Hole Saws & Accessory Kits, at today’s prices. Recalculated every night.

Price $15.99
Cheaper than about 73% of the 5,493 comparable items (median $27.99).

Specifications

Product
Brand nameDrill America
Product typeDrill Accessories

Questions about this item

What chuck size do I need to hold the 21/64 inch shank?

Use a drill chuck that opens to at least 21/64 inch (0.3281 inch) so the cobalt shank seats securely without slipping.

Will the 12 inch overall length reach through the same deep holes my shorter bits handle?

The 12 inch overall length and 3-5/16 inch flute extend reach significantly, letting you drill deeper in a single pass while the split point reduces wandering.

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