Chicago-Latrobe 47708 135° Cobalt Jobber Drill Bit

135° Cobalt Jobber Drill Bit

The Chicago-Latrobe 47708 is a 1/8 inch fractional drill bit designed for general-purpose metal drilling. Its 135-degree split point reduces walking and starts holes cleanly without a centre punch. The cobalt construction resists heat and wear better than standard high-speed steel. It suits maintenance technicians and fabricators who need reliable performance on stainless steel and other tough alloys.

Sustained heat resistance and chip control

Cobalt alloy retains hardness at higher temperatures, so the cutting edges stay sharp during repeated holes or deeper cuts. The split-point geometry produces smaller chips that clear the flutes more easily, lowering the risk of binding. Without coolant-through holes, the bit relies on external lubrication or periodic withdrawal to manage heat in prolonged operations.

Straightforward chuck fit and common pitfalls

The straight shank fits any standard three-jaw chuck sized for 1/8 inch or 3 mm capacity. No special adapters or collets are required. The most frequent issues are excessive feed pressure that chips the brittle cobalt edge and insufficient lubrication that accelerates wear. Using a pecking cycle and cutting fluid prevents both problems.