Microbore Tooling Systems

Fine Boring Systems & Deep Hole Drilling



Twinbore - Tribore Image

introduction to twinbore / tribore

Twinbore and Tribore provide a full range of rough boring tools which, through the rigidity of their design, enable high metal removal to yield increased productivity while maintaining levels of accuracy which, in most cases, will eliminate the need for semi-finishing operations.

design features

Tribore Image

Precision formed angular serrations provide high surface area contact and optimum design to absorb the cutting forces produced during normal rough machining and provide stable, quiet operation.

Each cutting edge has its own adjustment screw for the accurate setting of bore sizes and with the fixing screws operating on the spring plate, a high clamping pressure is provided over a large area to maintain stability during the machining operation.

The high clamping pressure, combined with the high surface area contact of the serration design, ensures optimum rigidity over the extensive adjustment range of the insert holder when used in both standard and step boring applications.

The overall rigidity of the design has been proven in the machining of bores with non-central cores and Tribore is ideally suited to the machining of bores  with interrupted cuts where the rugged construction is essential to cater for the resultant cutting forces.

All Twinbore and Tribore boring heads are supplied with coolant outlets for machines equipped with through the spindle coolant facilities.

Twinbore Image


Twinbore - Standard Boring - Diagram

For standard boring, two standard insert holders are set to identical dimensions both axially and radially.

The insert holders can be set to cut the same diameter, which permits machining twice as fast as conventional boring. Diameter changes are made by the adjustment screws. The insert holders can also be set to different cut diameters resulting in a greater diameter of cut but with a reduced feed rate.

Twinbore - Step Boring - Diagram

For step boring arrangement, one standard insert holder and one step boring insert holder are required. The step boring insert holder will set up approxiamtely 0.7MM behind the syandard (lead) insert holder.

Step boring holder = MTP_ _-107_ _

The leading insert cuts at one diameter and the following insert cuts a larger diameter.


Standard boring: Tribore can be used in a standard boring arrangement where three insert holders are set up to identical dimensions both radially and axially. The insert holders are set to cut the same diameter which permits machinning up to three times faster than conventional boring. Tribore will require more H.P. in extreme conditions.

Step boring: The step boring arrangement requires the use of a standadrd bore insert holder in posiition 1, a steo bore holder in position2 and a lead angle insert holder in position 3.