Curved thread CT55 and CT67

The unique and innovative curved thread systems CT55 and CT67, for surface mining and quarrying, are designed to handle higher drilling power compared to standard systems. The curved profile of the thread reduces stress levels in all the right places and every corner of the product is optimized for fatigue strength.


Shoulder driven system
− Efficient energy transfer
− Stiff and strong connection

Curved thread
− Bigger X-section where it’s needed
− Significantly reduced stress levels
− Robust coupling

Easy coupling / uncoupling
− Double thread entrances
− Minimal rattling

Unique thread, protected by several patents



Reaching higher productivity
- Faster rate of penetration per meter
- More meters per engine hour
- Problem-free drilling and easy coupling/uncoupling
- Good hole quality/hole straightness

Consuming less when drilling
- Lower fuel cost per drilled meter
- Less environmental impact, less CO2 emissions

Getting lower tool cost per meter and lower total drilling cost
- Good service life
- Less sudden breakages

CT55 (new T51)

Ø 89 - 115 mm (3½'' - 4½'')
70 mm flushing house
Rock Drills RD921, RD925, RD927

CT67 (new GT60)

Ø 102 - 140 mm (4'' - 5½'')
70 mm flushing house
Rock Drills RD927, RD930