QL Shank DTH Drill Bit

​QL Shank DTH Bit is mainly widely used for produce large-diameter holes in rocks for water-well drilling, tunnels, mineral exploration, geothermal drilling, subway engineering drilling....

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GMD could supply the QL Shank DTH Drill Bit with cemented carbide buttons have very good wear-resistant. Buttons are strong in the mining process and could meet requirements of various rocks , and the service lifetime is very long.

QL Shank DTH Drill Bit is widely used in underground mining, quarries, hydraulic and Hydro-Power Engineering, water well drilling, Mineral exploration, anchoring hole drilling, geothermal engineering, Subway excavation, another civil engineering. it has the advantage of high flatness, smooth hole wall, high rigid of drill rod and hammer, independent of high axial thrust, no limit of drilling depth, low cost of devices and easiness to maintain.


Shank Type: QL40, QL50, QL60, QL80

Bit Diameter: 105mm-605mm

Bit Face: Flat Face, Convex Face, Concave Face, Drop Center, Double Gauge.


QL Shank DTH Drill Bits 






How to Choose Right Bit Face Design?



Bit face shape selection:
1. Drop Center Bit
For high penetration rates in soft to medium hard and fissured rock formations. Low to medium air pressures. Maximum hole deviation control.
2. Concave Face
The all-round application bit face specifically for medium hard and homogenerous rock formations. Good hole deviation control and good flushing capacity.
3. Convex Face
For high penetration rates in soft to medium-hard with low to medium air pressures. It is the most resistance to steel wash, and may reduce the load and wear on the gauge buttons, but poor hole deviation control.

Tips on Drilling 

1. Starting the drill

- Firm footing for the drill

- Align and collar the hole properly

- Begin slowly and adjust the feed and throttle as the bit buries


2. Drilling

- Maintain enough rotation for good penetration

- Excessive rotation will wear the gauge

- Maintain correct feed pressure;

Insufficient air pressure leads to a loose drill string and premature wear

Sufficient air pressure is ideal to keep the bit from bouncing on the bottom

Too much pressure will buckle and bind the steel in the hole

Over feeding in hard rock will reduce penetration

Over feeding in soft rock can lead to burying the bit and hanging the steel


3. Drill dieseling

- Occurs with insufficient feed pressure

- Also happens with full throttle when withdrawing the bit

- Dieseling heats up the drill and burns off the lubricant

- Results could include a destroyed hammer

- Stop dieseling by reducing the drill throttle and increasing feed pressure



DTH Packing

Key Words:


QL Series DTH Bits

DTH Bits for Hard Rock Drilling

High Air Pressure COP Series DTH Bits for Hard Rock Drilling

DHD Shank DTH Bit

dth drill bit

dth hammer bit

DTH Button Bits

High Air Pressure DTH Button Bit

Large Diameter Button Bits

Down The Hole Drilling Tools



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