BTA/STS 
- BTA/STS drills are used for larger diameter drilling, typically 20 - 630mm [0.79 – 24.8 inch].
- High-pressure coolant is introduced around the tool from outside.
- Chips are discharged through the tool center and machine spindle.
- Compared to gun drilling, BTA/STS method provides higher penetration rates and has higher power requirements.
Machines with BTA/STS Capabilities:
- B-series (<6M)
- B-series (>6M)
- USC series
- USK series
- UNI series
- For the middle range diameters between 20-50mm [0.79-2.00 inch] Gundrill/BTA conversion attachments are available
