How to Drill Smaller Holes with BTA Head

How to Drill Smaller Holes with BTA Head

Generally, BTA drilling uses a tool head threaded or mounted on a long drill tube. The head has multiple cutting surfaces, which remove chips from the workpiece using high-pressure coolant. The chips are flushed through the center of the head and exhausted out the drill tube and machine spindle.

In order to achieve this, the drilling head includes a side cutting edge and a rake surface on the cutting blade corner. The rake surface is arranged around a first guide rail angle, which can be adjusted over an angular range of +- 10 deg to a nominal guide rail angle, measured in the circumferential direction from the cutting edge to the cutting corner.

This guide rail angle can be adjusted over an angular range that is at least equal to the length of the cutting edge (usually a minimum of 3.5mm), but typically between 1 and 5 mm. The adjustable guide rail angle increases the flexibility of using the drill head for different materials with different drilling parameters.

Another advantage is that the guide rail angle can be set at least over an angular range that is at most equal to the length of the minor cutting edge, e.g. a minimum of 2 mm.

This feature combination is particularly useful when machining some materials, especially those that have a relatively low wear resistance. It helps prevent oscillation during machining, which is known to have a negative impact on bore quality when machining some materials compared to others.