3.9mm Shank Size Drill Bits

Gold Oxide—Like black oxide, this finish adds wear resistance and reduces friction for improved chip flow. Because it’s less prone to flaking off, it offers better rust protection when bits aren't in use.

					Shank				Each
	Drill Bit Size, mm	Decimal Size Equiv.	Overall Lg., mm	Max. Drilling Dp., mm	Type	Size	Drill Bit Point Type		1-9	10-Up
Jobbers' Length







				Gold Oxide

				3.9	0.1535"	79	47.6	Round	3.9 mm	Split	000000000	00000	00000

Cobalt Steel Drill Bits

Jobbers' Length

Round Shank

Split

Tough and wear resistant, cobalt steel bits last at least twice as long as high-speed steel. They can also run up to 25% faster at higher temperatures without being damaged on hard materials, such as nickel.

Jobbers' Length—These bits have the balance of rigidity and length needed for most applications.

Uncoated—Polished to eject chips, these are also known as bright finish bits.

					Shank				Each
	Drill Bit Size, mm	Decimal Size Equiv.	Overall Lg., mm	Max. Drilling Dp., mm	Type	Size	Drill Bit Point Type		1-9	10-Up
Jobbers' Length







				Uncoated

				3.9	0.1535"	79	47.6	Round	3.9 mm	Split	00000000	00000	00000

Chip-Clearing Cobalt Steel Drill Bits

Jobbers' Length

Parabolic Flute

Round Shank

Split

Avoid clogs and dissipate heat with cobalt bits that last at least twice as long as high-speed steel. The flutes clear chips to improve coolant flow and prevent damage to the bit and the hole. They also speed up drilling since you don't have to stop to clear the bit manually.

Jobbers' Length—These bits have the balance of rigidity and length needed for most applications.

Uncoated—Polished to eject chips, these are also known as bright finish bits.

						Shank
	Drill Bit Size, mm	Decimal Size Equiv.	Overall Lg., mm	Max. Drilling Dp., mm	Flute Type	Type	Size, mm	Drill Bit Point Type		Each
Jobbers' Length







				Uncoated

				3.9	0.1535"	75	43	Parabolic	Round	3.9	Split	00000000	00000