Chicago-Latrobe 47359 12.2 mm HSS Black/Gold 118° jobber drill bit

12.2 mm HSS Jobber Drill Bit

The Chicago-Latrobe 47359 is a jobber-length twist drill made from high-speed steel with a black-oxide finish. Its 12.2 mm diameter and 118-degree radial point suit general-purpose drilling in steel, cast iron and similar ferrous metals. The bit is designed for use in handheld or stationary drill chucks where coolant feed is not available.

Practical limits of the 118-degree point

The 118-degree point angle provides reliable centring in mild steel but can wander in harder alloys or stainless without a pilot hole. High-speed steel retains hardness up to moderate cutting temperatures; sustained high-speed drilling in abrasive or heat-resistant materials will dull the edge faster than cobalt or carbide alternatives. The lack of coolant-through holes means chips must be cleared by frequent pecking or external flood coolant.

Replaces worn or undersized HSS jobber bits

This bit replaces a dull or damaged 12.2 mm HSS jobber drill when hole tolerance and finish quality have degraded. The upgrade is worthwhile when the previous bit shows excessive flank wear, chipping at the cutting lips or loss of centre accuracy. It does not address needs for coolant-fed drilling, carbide tool life or specialised point geometries for deep-hole or composite work.