Zoro Select 16W780 Cobalt Threaded Shank Drill 3/8 in 135° Point

Zoro Select Cobalt Drill 3/8 in

The Zoro Select 16W780 is a cobalt threaded-shank drill bit with a 3/8 inch diameter and a 135-degree split point. It targets machinists and maintenance technicians who need a durable bit for drilling hard metals such as stainless steel or titanium alloys. The black oxide finish adds lubricity and helps resist chip welding during repeated use.

1/4-28 Thread Limits Compatibility

The bit uses a 1/4-28 threaded shank rather than a straight round shank, so it only fits tools or adapters that accept that specific thread. It cannot be clamped in a standard three-jaw drill chuck or a quick-change hex holder without a matching threaded collet. The 135-degree point angle is optimised for rigid setups; hand-held drilling may cause the bit to walk on hard surfaces.

Install Into Threaded Holder Only

Installation requires threading the shank fully into a compatible 1/4-28 holder or collet until it seats firmly against the shoulder. Cross-threading is the most common issue if the threads are forced or misaligned at the start. Always verify the holder threads are clean and undamaged before fitting the bit to avoid run-out or shank damage.