BIG HOLES FROM THE SOLID IN SECONDS.

The author recommends the use of Kub carbide-insert drills for hole drilling because they have spiral flutes as opposed to the straight flute offered by all other drill manufacturers, and because they offer positive-rake tooling, while other drills have only negative or neutral rake. These two features make it possible to use less thrust on the drilling machines and thus to use them on all of conventional chucking machines with less required horsepower. As a result, the drilling rate can be increased by a minimum of 4. 5 times on every job for which the drills are suitable. In many cases it is possible to improve the drilling time by six or seven times, even up to 10. 2 times faster than conventional twist drills.