Buying guide for drilling aeronautical materials: aluminum, stainless steel and titanium

# Buying guide for drilling aeronautical materials: aluminum, stainless steel and titanium

Drilling is a crucial operation in the aviation industries, where the accuracy and quality of the holes are essential to ensure the safety and performance of aircraft. Commonly used materials, such as aluminum, stainless steel and titanium, require specific techniques and tools. This guide will provide you with tips and techniques for drilling these materials effectively.

# Drilling of aluminum

Aluminum is a relatively easy material to drill, but it requires specific techniques to achieve clean, burr-free results. 

To drill aluminum, use high-speed steel (HSS) or cobalt (HSS-Co) drill bits. These drill bits, like the HSS Cobalt 8% Drill Bit, are specially designed to withstand heat and wear, and provide a clean, precise cut.

Drilling techniques:

Choice of drill bit: opt for an HSS-Co cobalt drill bit, which is particularly effective at drilling through aluminum thanks to its ability to withstand the heat generated during drilling. These drill bits are available in different sizes, suitable for the width of the holes you want to drill.

Marking the hole: Mark the location of the hole using a pencil or a non-permanent marker. To ensure accurate drilling, use a needle to create a small indentation where the hole is to be made. This will prevent the drill bit from slipping on the smooth surface of the aluminum.

Workpiece Stabilization: Firmly fix the aluminum workpiece on a stable surface with clamps to prevent movement during drilling. To reduce the risk of burrs when coming out of the drill bit, place a wooden or plastic plate under the aluminum.

Speed Adjustment: Set your drill to a moderate to high speed. Aluminum is fairly easy to drill, but excessive speed could generate burrs or overheat the bit. A well-adjusted speed results in a clean, well-finished hole.

Drilling Execution: Start drilling at a slow speed to position the drill bit tip correctly. Then, gradually increase the speed while maintaining a constant pressure. Do not force the drill bit; Let it do its job of cutting. If burrs appear, it may indicate that the speed is too high or that the pressure is excessive.

To prevent burrs when drilling thin aluminum foils, place a plywood plate or piece of wood underneath. In addition, to ensure a consistent depth of the hole, you can mark the desired depth on the drill bit with tape.

# Drilling in stainless steel

Stainless steel, commonly known as stainless steel, is a hard and resistant material, often used for its anti-corrosion properties. However, drilling stainless steel can be tricky due to its hardness and tendency to accumulate heat. To achieve clean results without damaging your tools, it is essential to adopt the right techniques and use the right tools.

Drilling techniques:

Drill bit selection: Drilling stainless steel requires the use of cobalt drill bits (HSS-Co) or drill bits with a titanium nitride (TiN) coating. These types of drill bits, such as HSS cobalt 8%, are designed to withstand the high heat generated during drilling and offer better durability in the face of wear. Their reinforced tip allows better penetration into the hard material.

Surface preparation: Before drilling, it is crucial to properly prepare the surface of the stainless steel. Make sure that the area to be drilled is clean and dry, which will prevent slippage or inaccuracy when drilling. Use a needle to mark the location of the hole and create a small indentation, which will allow the drill bit to anchor well and not slip.

Speed and pressure control: To avoid overheating the drill bit and material, it is recommended to drill at a slow to moderate speed. Too high a speed can lead to excessive heat build-up, making drilling more difficult and damaging the bit. Apply consistent but moderate pressure, letting the drill bit do the work without straining. If you feel the bit stop or slow down, pause to avoid overheating. Depth management: Use a depth guide if possible, or mark the depth on the drill bit with tape.

Lubrication: Lubrication is essential when drilling stainless steel to reduce friction and heat. Use a specific cutting oil or metal lubricant, regularly applying a small amount directly to the drill bit and the area to be drilled. This will help cool the drill bit, extend its life, and get a cleaner hole.

Workpiece stabilization: Firmly attach the stainless steel workpiece to a stable surface to prevent movement during drilling. Since stainless steel is a hard material, any vibration or movement could compromise the accuracy of the hole. For thinner parts, placing a wooden or metal support under the stainless steel can help stabilize the part and reduce the chance of deformation or burrs. 

Cooling and breaks: Stainless steel tends to build up heat quickly, which can damage the drill bit. To avoid this, take regular breaks when drilling to allow the drill bit to cool down. You can also apply more lubricant to help with cooling. This technique extends the life of your tools and ensures efficient drilling.

# Titanium drilling

Titanium is a material known for its exceptional strength, light weight and ability to withstand high temperatures, making it a preferred choice in the aviation industry. However, these same properties make drilling titanium particularly difficult. To do this without damaging your tools or the workpiece, it's crucial to use the right techniques.

Drilling techniques:

Choice of drill: Titanium requires the use of high-strength drill bits, such as cobalt drill bits (HSS-Co) or with a titanium nitride (TiN) coating. HSS cobalt 8% drill bit is especially recommended for titanium due to its durability and ability to maintain an efficient cut even under high heat conditions. The reinforced tip of these drill bits allows for precise penetration into this hard material.

Drilling speed: Unlike other materials, titanium must be drilled at a slow speed. High speed would cause rapid overheating, leading to hardening of the titanium (work hardening effect), which would further complicate drilling. Start at a low speed and maintain a slow pace throughout the process to prevent over-curing of the material.

Constant pressure: When drilling titanium, it is essential to apply constant but controlled pressure. Too much pressure can break the bit, while insufficient pressure can lead to excessive friction and premature wear of the tool. Allow the drill bit to slowly progress through the material, maintaining steady pressure for a clean, efficient cut.

Intensive lubrication: Titanium dissipates heat poorly, which can cause rapid heat build-up at the drilling point. To minimize this, abundant lubrication is required. Use a specific metal lubricant, such as cutting oil, which is applied regularly to the drill bit and contact surface. This lubrication helps to cool the bit, reduce friction, and extend the life of the tool.

Heat management: Heat management is one of the most critical aspects when drilling titanium. In addition to lubrication, it is advisable to take regular breaks to allow the drill bit to cool. This not only prevents premature wear of the tool, but also damage to the titanium itself, which could warp or harden due to excessive heat.

Stabilizing the workpiece: Make sure the titanium workpiece is securely fastened before you start drilling. Any vibration or movement can not only compromise drilling accuracy, but also increase the risk of drill breakage. Stable support is essential, especially when drilling thicker or more complex parts.

# Using HSS Cobalt 8% Drill Bit

The HSS Cobalt 8% Drill Bit is a high-performance tool designed for manual drilling of Alu/Alu and Titanium/Alu stacks. Made in France, this drill bit offers several specific advantages: 

Cross Point Sharpening : Allows for easy self-centering on smooth surfaces, reducing the axial force required. 

Cylindrical shank : The diameter of the shank is equal to the diameter of the tip, which allows versatile use on power and CNC machines. 

118° tip : Tip angle suitable for general use in long-chip materials, allowing for fast material attack and easy centering.

Drilling different aeronautical materials such as aluminum, stainless steel and titanium requires specific tools and adapted techniques to achieve optimal results without damaging the surface or the tool. By following the tips and methods presented in this guide, you can drill these materials efficiently and safely. Always choosing the right drill bit for the material to be drilled and using the proper techniques will ensure you get quality work and extend the life of your tools. 

For the most demanding jobs, the HSS cobalt 8% drill bit is an excellent choice, offering precision and durability in drilling aeronautical materials.