Alfa USAs Cobalt M42 Silver and Deming drills are manufactured from heat resistant cobalt M42 high speed-steel to maintain cutting ability at temperatures exceeding 1000 degrees F. Silver and Deming drills are ideal for portable drilling and drill presses, where the maximum chuck capacity is 1/2 inch. Commonly used in machine shops, maintenance departments, garages and body shops. Also popular in screw machining centers where a short, rigid drill is desirable. **Not for enlarging existing holes.