Drivers

Drivers are manufactured from various materials depending on the hardness desired by a particular application. The spindles or tool holders determine the locking mechanisms prescribed for individual applications. The most common and standard is a two degree tapered flat in an under-cut centered in the driver. There are many variations subsequent to machine stroke limitations, small diameter deep hole applications require longer drivers to enable shorter tip and tube lengths. This allows for maximum surface feet per minute without the whip factor. Many machine manufacturers dictate the drivers' OD and lengths depending on the builder's geographic location hence, metric or imperil.

Driver design is important because of the high speeds and pressures used in the gundrilling process. Maximizing the gundrill driver length improves rigidity and concentricity.

 View Driver Ordering Guidelines
Tapered Flats
Two Tapered Flats 90° Apart Shown		 Straight Undercut
Straight undercuts are sometimes specified in addition to tapered locking surfaces. However, for safety, we recommend tapered undercuts and tapered flats for locking mechanisms.



DRIVER-FRONT ADJ
Minimum thread length (THL) should be at least equal to useable tip length + 1 to 2 thread diameters		 DRIVER-REAR ADJ
Bolt length should be ½ to 1 thread diameter longer than useable tip length + jam nut thickness.