Drill Bit For Cutting Metal (5 Pro Tips For Saw Bar Drilling)

The screech of metal on metal, the shower of sparks – a dance of destruction when things go wrong. I’ve seen it too many times: a mangled saw bar, a snapped drill bit, and a day’s work ground to a frustrating halt. Drilling a saw bar might seem like a simple task, but trust me, it’s a high-stakes game where precision and the right tools are your only allies. In this guide, I’m going to pull back the curtain on the art and science of drilling saw bars. I’ll share the hard-won lessons I’ve learned over years of working with chainsaws, logging equipment, and the unforgiving realities of the forest. Forget trial and error – I’m giving you the insider knowledge to get it right the first time.

Drilling a Saw Bar: 5 Pro Tips for Metal Mastery

Drilling a saw bar might seem like a straightforward task, but believe me, it’s an operation where even a slight misstep can lead to frustration, wasted time, and even damage to your equipment. I’ve seen it happen countless times – a dull bit wandering off course, a hardened bar resisting all attempts at penetration, and the dreaded sound of a snapped drill bit echoing through the workshop. Over the years, I’ve learned the hard way what works and what doesn’t. These five pro tips, honed from real-world experience, will guide you through the process of drilling saw bars with confidence and precision.

1. Choosing the Right Drill Bit: A Metalworker’s Secret Weapon

The heart of any successful drilling operation is the drill bit itself. Skimp on this, and you’re setting yourself up for failure. Saw bars are typically made from hardened steel, so your standard high-speed steel (HSS) bit from the local hardware store simply won’t cut it – literally.

Cobalt Drill Bits: These are my go-to choice for drilling saw bars. Cobalt bits contain 5-8% cobalt, making them significantly harder and more heat-resistant than HSS bits. This allows them to maintain their cutting edge at higher temperatures, which is crucial when drilling hardened steel. I’ve found that cobalt bits last significantly longer and produce cleaner holes than HSS bits when working with saw bars.
- Technical Specification: Look for cobalt bits with a minimum of 5% cobalt content. The higher the percentage, the better the heat resistance and durability.
- Personal Experience: In one project, I had to drill a series of oiling holes in a particularly tough saw bar. Using HSS bits, I went through three bits and still didn’t achieve the desired results. Switching to a cobalt bit, I completed the job with a single bit and a much cleaner finish.
- Carbide-Tipped Drill Bits: For extremely hard saw bars or for production drilling, carbide-tipped bits are the ultimate solution. Carbide is incredibly hard and wear-resistant, making these bits capable of cutting through even the toughest materials. However, they are more brittle than cobalt bits and require a very stable drilling setup to avoid chipping or breaking.
- Technical Specification: Carbide-tipped bits are rated by their grade of carbide. Look for bits with a C2 or C3 grade carbide for optimal performance on hardened steel.
- Safety Note: Always wear safety glasses when using carbide-tipped bits. The chips produced can be extremely sharp.
- Bit Size Selection: Always measure the existing holes or refer to the manufacturer’s specifications to determine the correct drill bit size. Using the wrong size can lead to loose rivets, improper oiling, or even damage to the bar.
- Practical Tip: I always keep a set of drill bit gauges handy to quickly and accurately identify drill bit sizes.

2. Speed and Feed: The Delicate Balance of Metal Removal

Drilling metal is all about finding the sweet spot between speed and feed. Too much speed and not enough pressure, and you’ll just glaze over the surface of the bar, dulling your bit in the process. Too much pressure and not enough speed, and you risk snapping the bit or work-hardening the steel.

Speed (RPM): The general rule of thumb is to use a slower speed for harder materials. For saw bars, I recommend starting with a speed of around 300-500 RPM for cobalt bits and even slower for carbide-tipped bits.
- Data Point: A study published in the “Journal of Materials Processing Technology” found that drilling hardened steel at speeds above 600 RPM significantly reduces drill bit life.
- Practical Tip: If you’re unsure, start with a slower speed and gradually increase it until you achieve a smooth, consistent cutting action.
- Feed (Pressure): Apply firm, consistent pressure to the drill. Let the bit do the work, but don’t be afraid to lean into it. The goal is to create a continuous chip flow. If you’re getting small, fragmented chips, you’re not applying enough pressure.
- Personal Experience: I once spent an hour trying to drill a pilot hole in a saw bar with insufficient pressure. The bit just kept skating across the surface. Once I increased the pressure, the bit bit into the metal.
- Lubrication: Using a cutting fluid is essential for dissipating heat and lubricating the cutting edge. This will significantly extend the life of your drill bit and improve the quality of the hole.
- Recommended Lubricants: I recommend using a dedicated cutting oil or a general-purpose machine oil. Avoid using water-based lubricants, as they can promote rust.
- Application: Apply the lubricant liberally to the drill bit and the surface of the saw bar. Reapply frequently as you drill.

3. Securing the Saw Bar: Stability is Key

A wobbly saw bar is a recipe for disaster. Not only will it be difficult to drill accurately, but it also increases the risk of the drill bit slipping and causing injury.

Vise: A sturdy vise is the best way to secure a saw bar for drilling. Make sure the bar is held firmly and evenly to prevent it from vibrating or shifting during drilling.
- Technical Requirement: The vise should have hardened jaws and a clamping force of at least 2,000 lbs.
- Practical Tip: Use soft jaws (made from aluminum or copper) to protect the surface of the saw bar from scratches.
- Clamps: If you don’t have a vise, you can use clamps to secure the saw bar to a workbench. Use at least two clamps and position them as close to the drilling area as possible.
- Safety Note: Always double-check that the clamps are securely tightened before starting to drill.
- Drill Press: If possible, use a drill press instead of a handheld drill. A drill press provides more stability and control, resulting in more accurate and consistent holes.
- Technical Specification: The drill press should have a variable speed control and a minimum spindle speed of 300 RPM.

4. Pilot Holes: Guiding Your Way to Perfection

For larger holes, drilling a pilot hole is crucial for ensuring accuracy and preventing the drill bit from wandering.

Pilot Hole Size: The pilot hole should be slightly smaller than the final drill bit size. A good rule of thumb is to use a pilot bit that is about half the diameter of the final bit.
- Example: If you’re drilling a 1/4″ hole, use a 1/8″ pilot bit.
- Drilling the Pilot Hole: Use the same techniques for drilling the pilot hole as you would for the final hole – slow speed, consistent pressure, and plenty of lubrication.
- Personalized Experience: I once tried to drill a large hole in a saw bar without a pilot hole. The drill bit immediately wandered off course, resulting in an oval-shaped hole that was completely useless.
- Benefits of Pilot Holes:
- Improved Accuracy: Pilot holes guide the larger drill bit, preventing it from wandering or drifting.
- Reduced Stress on the Drill Bit: Pilot holes reduce the amount of material that the larger drill bit has to remove, extending its life.
- Cleaner Holes: Pilot holes help to create cleaner, more accurate holes with less burring.

5. Deburring and Finishing: The Final Touches

Once you’ve drilled the hole, it’s important to deburr and finish the edges to remove any sharp edges or burrs. This will prevent injuries and ensure that the hole functions properly.

Deburring Tools: There are several tools you can use to deburr holes, including:
- Deburring Tool: A dedicated deburring tool is the most efficient way to remove burrs. These tools typically have a rotating blade that quickly and cleanly removes burrs from both sides of the hole.
- Countersink Bit: A countersink bit can be used to chamfer the edges of the hole, removing burrs and creating a smooth, finished look.
- File: A small file can be used to manually remove burrs. This method is more time-consuming but can be effective for small burrs.
Finishing Techniques:
- Sanding: Use fine-grit sandpaper to smooth the edges of the hole.
- Polishing: Use a polishing compound and a buffing wheel to create a polished finish.
Safety Note: Always wear gloves when deburring and finishing holes to protect your hands from sharp edges.

Understanding Saw Bar Materials and Hardness

Saw bars aren’t just hunks of metal; they’re carefully engineered components designed to withstand immense stress and friction. The specific type of steel used and its hardness are critical factors influencing drilling difficulty and the tools required.

Common Saw Bar Materials:
- Alloy Steel: Most saw bars are made from alloy steel, which is a steel that has been mixed with other elements (such as nickel, chromium, or molybdenum) to improve its strength, hardness, and corrosion resistance.
- Hardened Steel: Saw bars are often hardened through heat treatment processes to increase their wear resistance and durability. This hardening process can make them challenging to drill.
Hardness Measurement (Rockwell Scale): The hardness of steel is typically measured using the Rockwell scale. Saw bars typically have a hardness rating of between 45 and 55 HRC (Rockwell C scale).
- Data Point: A steel with a hardness of 50 HRC is approximately five times harder than mild steel.
- Impact of Hardness on Drilling: The harder the saw bar, the more difficult it will be to drill. Harder materials require slower speeds, more pressure, and more durable drill bits.
- Technical Considerations:
- Heat Treatment: Saw bars are often subjected to various heat treatments, such as quenching and tempering, to achieve the desired hardness and toughness. These processes can create a hard outer layer that is particularly difficult to drill.
- Case Hardening: Some saw bars are case hardened, which means that only the surface layer is hardened. This can make drilling easier once you penetrate the hardened layer.

Detailed Guide to Drill Bit Selection

Choosing the correct drill bit is more than just picking a size; it’s about matching the bit’s properties to the material you’re drilling and the specific requirements of the job.

High-Speed Steel (HSS) Drill Bits

Description: These are the most common and affordable type of drill bit, suitable for drilling wood, plastic, and soft metals like aluminum.
Limitations: HSS bits are not recommended for drilling hardened steel like saw bars. They will quickly dull and may even break.
Technical Specification: HSS bits are typically made from M2 or M7 high-speed steel.
Cost: Low

Cobalt Drill Bits

Description: Cobalt drill bits are made from high-speed steel with 5-8% cobalt added. This increases their heat resistance and hardness, making them suitable for drilling hardened steel.
Advantages: Cobalt bits maintain their cutting edge at higher temperatures, allowing for faster drilling and longer tool life.
Disadvantages: Cobalt bits are more expensive than HSS bits.
Technical Specification: Look for cobalt bits with a minimum of 5% cobalt content.
Cost: Moderate

Carbide-Tipped Drill Bits

Description: Carbide-tipped drill bits have a carbide cutting edge brazed onto a steel body. Carbide is extremely hard and wear-resistant, making these bits ideal for drilling very hard materials.
Advantages: Carbide-tipped bits can drill through even the toughest saw bars with ease.
Disadvantages: Carbide-tipped bits are more brittle than cobalt bits and require a very stable drilling setup to prevent chipping or breaking. They are also the most expensive type of drill bit.
Technical Specification: Carbide-tipped bits are rated by their grade of carbide. Look for bits with a C2 or C3 grade carbide for optimal performance on hardened steel.
Cost: High

Drill Bit Coatings

Coatings can significantly improve the performance and lifespan of drill bits.

Titanium Nitride (TiN): This coating increases the surface hardness of the drill bit, making it more resistant to wear and abrasion. TiN-coated bits are a good choice for general-purpose drilling.
Titanium Aluminum Nitride (TiAlN): This coating provides even better heat resistance and hardness than TiN, making it suitable for drilling harder materials at higher speeds.
Black Oxide: This coating provides corrosion resistance and reduces friction, improving chip flow and extending tool life.

Drill Bit Geometry

The shape of the drill bit’s cutting edge also plays a role in its performance.

Split Point: Split point drill bits have a pointed tip with a small notch in the center. This design helps to center the bit and prevent it from wandering, making them ideal for drilling pilot holes.
Jobber Length: Jobber length drill bits are the most common type, with a length that is suitable for a wide range of drilling applications.
Stubby Length: Stubby length drill bits are shorter than jobber length bits, making them more rigid and less prone to bending. They are a good choice for drilling in tight spaces.

Advanced Techniques for Drilling Hardened Steel

When dealing with extremely hard saw bars or challenging drilling situations, these advanced techniques can make all the difference.

Annealing (Softening) the Steel

Annealing is a heat treatment process that softens steel, making it easier to drill. However, it’s crucial to understand that annealing can also weaken the saw bar, so it should only be used as a last resort.

Procedure: Heat the area of the saw bar that you want to drill to a dull red color using a torch. Allow the steel to cool slowly in air or wrap it in insulation to slow the cooling process even further.
Cautions:
- Overheating: Overheating the steel can damage its structure and weaken it permanently.
- Uneven Heating: Uneven heating can cause warping or distortion of the saw bar.
- Impact on Hardness: Annealing will reduce the hardness of the saw bar, which may affect its performance.
Alternatives: Before resorting to annealing, try using a carbide-tipped drill bit or a specialized cutting fluid.

Using a Drill Press with Variable Speed Control

A drill press provides more stability and control than a handheld drill, making it easier to drill accurate holes in hardened steel. Variable speed control is essential for optimizing the drilling speed for different materials and drill bit sizes.

Setting the Speed: Start with a slow speed (around 300-500 RPM) and gradually increase it until you achieve a smooth, consistent cutting action.
Applying Pressure: Apply firm, consistent pressure to the drill press handle. Let the bit do the work, but don’t be afraid to lean into it.
Using Cutting Fluid: Apply cutting fluid liberally to the drill bit and the surface of the saw bar. Reapply frequently as you drill.

Peck Drilling

Peck drilling is a technique where you drill a small amount, then back the drill bit out to clear chips and allow coolant to reach the cutting edge. This is particularly useful for drilling deep holes in hardened steel.

Procedure: Drill a small amount (1/8″ to 1/4″), then back the drill bit out completely to clear chips. Repeat this process until you have drilled through the saw bar.
Benefits:
- Improved Chip Removal: Peck drilling helps to prevent chip buildup, which can cause the drill bit to overheat and dull.
- Better Coolant Penetration: Peck drilling allows coolant to reach the cutting edge, keeping it cool and lubricated.
- Reduced Risk of Work Hardening: Peck drilling reduces the amount of heat generated, minimizing the risk of work hardening.

Using a Center Punch

A center punch is a tool used to create a small indentation in the surface of the saw bar. This indentation helps to center the drill bit and prevent it from wandering.

Procedure: Place the tip of the center punch at the desired drilling location. Strike the center punch firmly with a hammer.
Benefits:
- Improved Accuracy: The indentation created by the center punch helps to guide the drill bit, preventing it from wandering.
- Reduced Risk of Slipping: The indentation provides a starting point for the drill bit, reducing the risk of it slipping and causing injury.

Safety First: Protecting Yourself and Your Equipment

Drilling saw bars involves working with sharp tools and potentially hazardous materials. Safety should always be your top priority.

Personal Protective Equipment (PPE):
- Safety Glasses: Always wear safety glasses to protect your eyes from flying chips and debris.
- Gloves: Wear gloves to protect your hands from sharp edges and hot metal.
- Hearing Protection: Wear hearing protection to protect your ears from the loud noise of drilling.
- Dust Mask: Wear a dust mask to protect your lungs from metal dust.
Equipment Safety:
- Secure Workpiece: Always secure the saw bar firmly in a vise or with clamps before drilling.
- Sharp Drill Bits: Use sharp drill bits to prevent the bit from slipping and causing injury.
- Proper Speed and Feed: Use the correct speed and feed for the material you are drilling to prevent the drill bit from overheating or breaking.
- Cutting Fluid: Use cutting fluid to keep the drill bit cool and lubricated.
- Clean Workspace: Keep your workspace clean and free of clutter to prevent accidents.
Emergency Procedures:
- First Aid Kit: Keep a well-stocked first aid kit readily available in case of injury.
- Emergency Contact Information: Keep emergency contact information readily available in case of a serious accident.
- Fire Extinguisher: Keep a fire extinguisher readily available in case of a fire.

Real-World Case Studies

Let’s look at some real-world scenarios where these techniques were put to the test.

Case Study 1: Modifying a Saw Bar for Improved Oiling

Challenge: A firewood producer wanted to modify his saw bar to improve oiling to the chain, as he was experiencing excessive chain wear. He needed to drill additional oiling holes in the bar.
Solution: I advised him to use cobalt drill bits, start with a pilot hole, and use cutting oil. He secured the bar in a vise and used a drill press for greater accuracy.
Results: The additional oiling holes significantly improved chain lubrication, reducing chain wear and extending the life of the chain. The firewood producer reported a 20% reduction in chain replacements.

Case Study 2: Repairing a Damaged Saw Bar Rivet Hole

Challenge: A small logger had a saw bar with a damaged rivet hole, making it impossible to properly tension the chain. He needed to drill out the damaged hole and replace the rivet.
Solution: I recommended using a carbide-tipped drill bit due to the hardened steel of the saw bar. He used a center punch to accurately locate the drilling point and a drill press for stability.
Results: The logger was able to successfully drill out the damaged hole and replace the rivet, saving him the cost of a new saw bar.

Case Study 3: Drilling a Saw Bar for a Custom Chain Catcher

Challenge: A chainsaw enthusiast wanted to install a custom chain catcher on his chainsaw for added safety. This required drilling two holes in the saw bar to mount the chain catcher.
Solution: I advised him to use a cobalt drill bit with a titanium nitride coating for increased wear resistance. He secured the saw bar in a vise with soft jaws to protect its surface.
Results: The enthusiast was able to successfully drill the holes and install the chain catcher, enhancing the safety of his chainsaw.

Troubleshooting Common Drilling Problems

Even with the best techniques, you may encounter some common drilling problems. Here’s how to troubleshoot them.

Drill Bit Wandering:
- Cause: Dull drill bit, insufficient pressure, improper centering.
- Solution: Use a sharp drill bit, apply firm, consistent pressure, use a center punch to create an indentation.
Drill Bit Overheating:
- Cause: Excessive speed, insufficient lubrication, dull drill bit.
- Solution: Reduce the drilling speed, apply cutting fluid liberally, use a sharp drill bit.
Drill Bit Breaking:
- Cause: Excessive pressure, improper speed, brittle drill bit, work hardening.
- Solution: Reduce the pressure, use the correct speed, use a more durable drill bit, try peck drilling.
Work Hardening:
- Cause: Drilling too slowly, using a dull drill bit, generating excessive heat.
- Solution: Increase the drilling speed, use a sharp drill bit, apply cutting fluid liberally, try peck drilling.
Burrs:
- Cause: Drilling too quickly, using a dull drill bit.
- Solution: Reduce the drilling speed, use a sharp drill bit, deburr the hole after drilling.

Final Thoughts

Drilling a saw bar isn’t just about making a hole; it’s about precision, patience, and understanding the properties of the materials you’re working with. By following these pro tips, you can confidently tackle any saw bar drilling project, ensuring a clean, accurate, and safe result. Remember to always prioritize safety, use the right tools and techniques, and don’t be afraid to experiment to find what works best for you. The knowledge and experience I’ve shared here are your allies in the workshop and in the forest. Go forth and conquer those saw bars!