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Chicago-Latrobe

Chicago-Latrobe 11145 #21 135° Aircraft Extension Drill

SKU CH-CGZM-S99FC

A #21 aircraft extension drill bit with a 135-degree split point, high-speed steel construction, and black oxide finish for wire and machining applications

  • 135° split point starts cleanly on hard alloys
  • High-speed steel with black oxide resists wear in production runs
  • 28° helix clears chips from deep holes efficiently
  • #21 wire gauge matches NAS-type aircraft specifications
  • 4×D length reaches 2 1/8 in depth in one pass

Chicago-Latrobe 11145 Aircraft Extension Drill

The Chicago-Latrobe 11145 is a NAS-type aircraft extension drill designed for precision drilling in aerospace and industrial maintenance. It suits mechanics and technicians who require accurate hole placement in deep or confined structural assemblies.

Split point geometry with 135 degree angle

The 135-degree split point centres the drill immediately without a centre punch, reducing walk on curved or hardened surfaces. High-speed steel with black oxide finish resists heat buildup during sustained drilling, while the 28-degree helix clears chips efficiently at maximum depth.

Straight shank fits standard chucks and collets

The straight shank allows quick installation in drill motors, angle drills or CNC tool holders without adapters. Users must match the #21 wire gauge size to the fastener specification; the 4xD length-to-diameter ratio limits rigidity in very deep holes.

Highlights

  • 135° split point starts cleanly on hard alloys
  • High-speed steel with black oxide resists wear in production runs
  • 28° helix clears chips from deep holes efficiently
  • #21 wire gauge matches NAS-type aircraft specifications
  • 4×D length reaches 2 1/8 in depth in one pass

Specifications

BrandCHICAGO-LATROBE

Questions about this item

How much heat does the 135-degree split point generate during extended drilling?

The 135-degree split point on the high-speed steel bit is designed to reduce thrust and heat buildup, while the black oxide finish helps dissipate heat during continuous use.

What chuck size is required to hold the #21 wire-gauge shank?

The drill features a #21 wire-gauge shank that fits standard drill chucks capable of gripping small-diameter round shanks.

Will the 4xD flute length reach through my existing 2-inch workpieces?

With a maximum drilling depth of 2 1/8 inches, the 4xD flute length clears 2-inch thick material in a single pass.

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