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Chicago-Latrobe 11027 aircraft extension drill bit 29/64 inch HSS black oxide finish

Chicago-Latrobe

Chicago-Latrobe 11027 135 Degree NAS-Type Aircraft Extension Drill 29/64 in HSS Black Oxide

SKU CH-3V98-RPAZ1

Aircraft extension drill with 29/64 in fractional size, 135 degree split point and black oxide finish for high-performance machining

  • 135-degree split point starts holes cleanly
  • High-speed steel withstands high cutting temperatures
  • Black oxide finish reduces friction and chip welding
  • 29/64-inch fractional size fits standard tooling
  • 4-3/16-inch depth capacity reaches deep workpieces

Aircraft Extension Drill 29/64 in

The Chicago-Latrobe 11027 is a NAS-type aircraft extension drill built for deep-hole drilling in aerospace and maintenance applications. Its 135-degree split point reduces walk and starts cleanly in tough alloys. Machinists and technicians working on airframe structures will value the extended reach for restricted access points.

Thermals noise and power draw

High-speed steel construction with black oxide finish manages heat during prolonged drilling cycles in high-performance machining grades. The 135-degree point geometry lowers cutting forces, which reduces motor load and vibration on the power tool. Operators experience steadier cutting action with less chatter across the 4 3/16 in maximum drilling depth.

Build quality and connectors

The fractional-inch shank fits standard drill chucks without adapters, while the 4xD proportion balances rigidity and reach for 29/64 in holes. Black oxide coating adds corrosion resistance and helps retain lubricant during operation. Builders needing larger diameters or shorter stub-length drills will need a different tool.

How it compares

Measured against everything we stock in Power Drills, Drivers & Cutting Bits, at today’s prices. Recalculated every night.

Price $20.99
Cheaper than about 81% of the 2,412 comparable items (median $81.99).

Specifications

Product
Brand nameCHICAGO-LATROBE

Questions about this item

How do I install the 11027 drill bit in my drill chuck and what step is often missed?

Open the chuck fully, insert the shank completely, and tighten securely. The step often missed is ensuring the split point seats straight so the 135-degree angle cuts true.

What maintenance or replacement will the 11027 bit need after repeated use?

The high-speed steel cutting edges will dull over time. Resharpen the 135-degree split point to original geometry or replace the bit when drilling performance drops.

What limit appears first when using the 11027 bit continuously in deep holes?

Chip evacuation becomes the limiting factor at the 4 3/16 inch maximum drilling depth. The 28-degree helix angle moves chips, but deep cuts require frequent pecking to clear them.

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