What Is a Gun Drill?
A gun drill is a specialized tool designed for deep hole drilling, originally developed for manufacturing gun barrels. It operates by ejecting high-pressure cutting oil through its tip, removing chips during the drilling process, and allowing for the drilling of deep or narrow holes in a single operation. With its excellent linearity, a gun drill is capable of creating precise holes in hard-to-machine materials such as stainless steel and heat-resistant alloys.
Uses of Gun Drills
Gun drills are ideal for drilling holes with depths over five times their diameter, particularly for diameters ranging from 3 to 30 mm. Their ability to eject chips during drilling makes them highly efficient and accurate for deep-hole drilling. Common applications include:
- Food Machinery: Parts for liquid filling machines, coolers, dairy milking machines, and other food processing equipment.
- Transportation Equipment: Components for automobiles, railroad cars, and aircraft.
- Industrial Machinery: Spindles, shafts, cylinders, injectors, hydraulic systems, and gear reducers.
- Electricity: Parts for electrical and electronic devices, semiconductor heat plates, and LCD manufacturing equipment.
Principle of Gun Drills
Gun drills utilize a high-pressure pump to inject cutting oil into the cutting area. The drill’s hollow design facilitates the circulation of cutting fluid, which carries chips out through a V-shaped groove in the drill’s shank. Different drill tip designs, such as kidney or two-hole types, offer variations in oil delivery and head rigidity. The long shanks of gun drills often require a drill bush at the machining point to enhance bending rigidity, ensuring minimal misalignment and high precision in drilling.
Other Information on Gun Drills
1. Gun Drilling Machines
Gun drilling is performed on dedicated machines, which are specialized lathes designed for this process. Unlike traditional lathes, the material is stationary while the gun drill rotates. Continuous injection of cutting oil from the drill’s tip prevents hole blockage and damage to the drill. Gun drills have a driver at their base, allowing them to be held by the machine’s chuck, with cutting fluid supplied through the drill’s shank.
2. Gun Drilling on Machining Centers
While dedicated gun drilling machines are ideal, gun drilling can also be performed on general-purpose machining centers, NC milling machines, and NC lathes for hole depths up to approximately 40 times the hole diameter. These machines must have a center-through coolant function. Due to the gun drill’s cutting-edge design, a pilot hole is typically required to initiate the drilling process to precise specifications.