Deep Drilling Gun Drill

Deep drilling gun drill is designed for boring and counter-boring deep hole with depth more than 5 times its diameter. As one kind of downstream products of tungsten carbide tips and rods, they are capable of effectively trepanning holes at high depth-to-diameter ratios more effectively, compared to other hole making tools like twist drills and reamers.

The first element distinguishes deep drilling gun drill from other conventional hole drill tools are its special chips evacuating way. Pumped coolant (under pressure of approx. 9.5MPA) through a groove flush all chips away, which better solves the issue of cooling and lubrication when drilling deep holes.

For another thing, there are special three cutting edges and guide blocks.

During gun drilling, the three cutting edges function as a chip breaker. They cut off swarf and facilitate chip evacuation. Thus, no more chips do not rub against the machined surface. As to guide blocks, extra radial force and circumferential force is well received by the guide block, which also enables gun drill is well guided.

Working components of deep drilling gun drill

Cutting tip:

The cutting tip is a key part of the entire gun drill, and its specially designed geometry ensures that the cutting work proceeds by its anti-vibration ability. There is a crescent or dual holes on tip connecting oil passage of the flute shank through which the high-pressure coolant can reach the cutting zone and carry the chips out of the workpiece.

Flute shank:

Flute shank is made of special quenched alloy steel. You will find a 110 to 120 degree of V-shaped groove. The high pressure cutting coolant passes through core hole of drive hilt and flute shank then leaves via the V-shaped groove at last.

Drive hilt:

The cylindrical drive hilt has a brazed bush at the joint where the flute shank is attached to. The bush avoids breakage of flute shank caused by stress concentration as drilling. Generally, there is a recess on its neck for the clamping sleeve to lock the entire drill bit.

Application of deep drilling gun drills

Remain useful in automobile industry, aerospace industry, construction industry, medical equipment industry, oil & air pressure industry and other fields. Typical examples are the processing of the gear shaft and piston pin in the auto industry.

Processing capacity of gun drill

Standard deep drilling gun drills are able to cut out holes in diameter up to 1.5 mm(0.059”) to 76.2(3”) mm and depth of 100 times the diameter. Besides, we’ve gotten some purpose-built gun drill for machining deep holes in diameter of 152.4mm(6”) and depth of 5080mm(200”).

Gun drills readily produce not only deep holes but also shallow holes ( in diameter to length ratio 1:1). Just after a single feed, a shallow hole in surface precision (IT6-IT8 grade), straightness (0.16-0.33/1000), and roughness (Ra3.2-Ra0.1) are easily formed.

In general, we ensure the quality of our solid gun drills and tips by meeting the following requirements:

Straightness: 1/1000 by rotating of drill bit. 0.5/1000 by rotating of workpiece. 
Surface tolerance:  IT6-IT8 
Roughness:  Ra0.4-Ra3.2
drilling parameters for different materials

In addition, we supply TiN and TiCN coated gun drill tips as per different material to be processed. TiN(golden) coated ones are for steel parts that will produce long chips. While TiCN coated ones(dark colored) are for high content alloy machining. We also can manufacturer and design customized carbide gun drill tips for our clients.