In the world of tunneling and drifting, accuracy is paramount. A hole that deviates by even 2% can lead to poor fragmentation, dangerous "bootlegs" (unexploded charges), and excessive "over-break" that requires expensive concrete filling. For a tunnel to stay within its designed profile, every hole must be drilled exactly where the engineer intended. YKdrill has addressed this challenge by re-engineering the fluid dynamics and button geometry of the bit face.
The Power of Symmetry and Flushing: Hole deviation is often caused by uneven flushing or asymmetrical wear. If one side of the bit dulls faster than the other, the bit will naturally "walk" along rock veins or fractures, leading to a curved hole. YKdrill’s Guided Bit Series utilizes a perfectly balanced, computer-optimized button layout. By distributing the cutting load evenly across the face, the bit maintains its center of gravity. Additionally, our "Power-Flow" flushing grooves are wider and deeper, ensuring that rock cuttings are evacuated instantly. When cuttings aren't removed, they accumulate on one side of the bit, creating a pivot point that forces the bit off-course.
Conquering "Bad Ground" with Retrac Technology: Tunneling often involves passing through fault zones and fractured rock. This is where standard bits get stuck. A "stuck steel" incident can cost a shift half a day of productivity. YKdrill’s Retrac bits are the industry’s insurance policy. Featuring cutting flutes on the rear of the bit body, they allow the operator to rotate and hammer while pulling back. This "reverse drilling" clears collapsing rock from the hole, allowing for safe retraction. Our 2026 Retrac series features a 12% longer skirt, which provides extra stability in the hole and further reduces deviation in soft, shifting ground.
Case Study: The Alpine Tunnel Project: During a recent infrastructure project in the Alps, a contractor faced a 5% over-break rate due to hole deviation in gneiss rock. After switching to YKdrill T38 Guide bits, the over-break was reduced to 1.5%. This not only saved the contractor $12,000 per month in concrete costs but also allowed for a faster advance rate due to cleaner blast faces.
Conclusion: For contractors who value "meterage over excuses," YKdrill provides the specialized tools needed to conquer the most complex underground environments with surgical precision.
