Pilot & Spot Drills
Pilot & spot drills are often necessary for applications where the succeeding drill is longer than 10xD, or smaller than Ø 1.00 mm. The short, rigid length of most pilot and spot drill geometries can also be used to improve hole location.
When selecting a starter drill it is important for it to have an equal or larger point angle and diameter than the more delicate succeeding drill. This helps guide it towards centerline of the starter hole without damaging the integrity of the drill point, resulting in optimization of hole location and tool life.