Popular 18 X 12″ Aircraft Extension Drill Bit Cobalt GLBCOX1218

Diameter: #18

Overall length: 12″ (304.8 mm)

Material: Cobalt alloy steel (high-hardness, heat-resistant HSS variant)

Type: Aircraft extension twist drill bit

Quantity: 1 piece

Long-reach 12″ extension enables access to deep or recessed holes in tight spaces common in aircraft maintenance, automotive work, and industrial fabrication

Cobalt alloy construction provides greater hardness and heat resistance than standard HSS, improving wear life when drilling through tougher metals (e.g., stainless steel, alloy steels)

Designed for repeated high-temperature drilling, reducing edge dulling during prolonged use

Specifically suited for metalworking tasks that require precise hole placement in constrained layouts

Not intended for wood, masonry, or composites

Length: 12″ extension

Diameter: #18

Material: Cobalt alloy steel

Shape: Twist drill with extension reach