Tools made of today's ultramodern materials such as solid-carbide, Cermet, or diamond demand ever better quality spindles in regard to stability, run-out and RPM. The MSBS line of drill heads satisfies these demands. The spindles are held with a set of 3 pre-loaded precision angular contact bearings. This special bearing-system gives a very rigid support to our spindles and guarantees a low TIR (total indicator run-out). HSK- or Komet-ABS spindle noses are available as well as weldon, whistle-notch or spindles with collet type nose (ER-collets). The gears are heat-treated and surface ground to allow high RPMs with minimal vibration.

Design
Berger MSBS multi spindle drill heads are precision made. The housing is made out of a special aluminum used in the aircraft industry, but housings made out of cast iron or steel are available as well. Our spindles are double case hardened, aged and precision ground. All gears and other rotating parts are case hardened and ground. To optimize the efficiency they are held in ball bearings only. The spindles are held by a special bearing system:

Upper needle bearing
This bearing takes a portion of the load created in the gear trim, giving additional support to the spindle.

Spindle bearing system
This system with two paired angular-contact bearings in the front to take the axial thrust and one angular-contact bearing working as a counter bearing to preload this system gives a very rigid support to the spindle. The outer distance-ring is directly machined into the housing. The inner distance-ring is machined to match the outer distance-ring and the preloading-specifications of the used angular-contact bearings.

Different Housings
The length of the housings for our multiple drill heads depends on the following facts:

1. Housing with shallow upper part
   The gears are located on two different planes in the lower part of the housing. We use this construction for patterns with fewer spindles and bigger center to center distances as well as from the center of the drill head.
2. Housing with high upper part
   The gears are located on three planes, also above the intermediate plate. This construction allows for more spindles. In addition it also allows to vary the ratio of the spindles. This is to compensate for smaller drills or to allow threading of threads with different pitches in the same drill head. This construction is the most common.
3. Housing with high upper part and two intermediate plates
   This construction uses two intermediate plates, to allow for spindles close or in the center of the drill head.