Milwaukee Cobalt Drill Bit

As a DIY enthusiast and occasional metalworker, I've always been on the lookout for reliable drill bits that can handle a variety of materials without giving up midway through a project. Recently, I had the opportunity to put the Milwaukee Cobalt Drill Bit, specifically the 48-89-2302 model, to the test. This drill bit is marketed as a robust solution for hard metals, PVC, and wood, boasting features like a 135° split point for precision starting and a variable helix design for efficient material extraction. Here's my detailed take on its performance.

First Impressions

The Milwaukee Cobalt Drill Bit immediately feels like a high-quality tool. The cobalt alloy coating gives it a sturdy appearance, and the 3-Flat Secure-Grip™ design ensures it stays firmly in the chuck, which is a godsend when you're working on intricate projects. The 135° split point tip promises to prevent walking, a feature that caught my attention right away because precision is crucial in my line of work.

Performance in Hard Metals

My first project with this drill bit involved drilling through a 3/16" thick hardened steel plate for a shed door hinge. I started with the smallest bit to create pilot holes and gradually moved to larger sizes. The bit cut through the steel effortlessly, producing clean, precise holes without any wandering. I used cutting fluid and maintained a slow drill speed, which I believe contributed to the bit's performance. Over 30 holes later, the bit still felt sharp and effective. This was particularly impressive given my past experiences with other bits that dulled quickly or broke under similar conditions.

Challenges with Stainless Steel and Cast Iron

However, the bit's performance wasn't flawless across all materials. When I tried to enlarge holes in stainless steel brackets, the bit struggled. Despite using cutting oil and maintaining a slow speed, the bit produced only tiny chips and dulled after just a couple of holes. This was a significant letdown, especially since the bit is marketed as suitable for hard metals. Similarly, drilling into cast iron pipes was a frustrating experience. The bit wore out quickly, and I found myself replacing it far sooner than I'd expected.

Versatility in Other Materials

Switching gears, I tested the bit on PVC and wood. Here, the bit excelled. Drilling through PVC was like slicing through butter, and the bit maintained its sharpness throughout multiple holes. In wood, the bit was equally effective. It produced clean holes without splintering, although I did notice that using a sacrificial backing piece helped maintain the cleanliness of the exit holes. This versatility makes the bit a good candidate for mixed-material projects, although its primary strength lies in softer materials compared to hard metals like stainless steel.

Durability and Edge Retention

One of the standout features of this drill bit is its edge retention. In applications where it performed well, the bit maintained its sharpness impressively. For instance, after drilling multiple holes in mild steel, the bit showed minimal signs of wear. However, the same couldn't be said for harder materials. The bit dulled quickly in stainless steel and cast iron, which raises questions about its long-term durability in more demanding applications.

Ease of Use

The 135° split point tip genuinely helps with precise starting, reducing the need for pilot holes in many cases. This feature, combined with the 3-Flat Secure-Grip™, makes the bit easy to use even for less experienced DIYers. The bit didn't walk or wander, which is a common issue with lower-quality bits. This ease of use is a significant advantage, especially for those who might not have access to a drill press and rely on hand drills for their projects.

Customer Support and Warranty

One aspect that deserves mention is Milwaukee's customer support. In instances where the bit failed prematurely, I reached out to their customer service and was pleasantly surprised by their responsiveness. They replaced faulty bits quickly and without hassle, which is a reassuring factor for anyone investing in these tools. While customer support can't entirely make up for a tool's shortcomings, it does add value to the overall experience.

Conclusion

The Milwaukee Cobalt Drill Bit has its strengths and weaknesses. It excels in softer materials like PVC and wood and performs admirably in mild steel with proper technique and cutting fluid. However, its performance is less reliable in harder metals like stainless steel and cast iron, where it tends to dull quickly and struggle to maintain its edge.

Would I recommend this drill bit? Yes, but with reservations. If your projects primarily involve softer materials or mild steel, this bit will serve you well. Its durability, ease of use, and the backing of Milwaukee's customer support make it a worthwhile addition to your toolkit. However, if you frequently work with harder metals, you might want to consider other options that are specifically designed for those applications.

In summary, the Milwaukee Cobalt Drill Bit is a solid choice for general-purpose drilling, especially for DIY enthusiasts and occasional metalworkers. Just be mindful of its limitations with harder materials, and you'll find it to be a reliable and valuable tool in your collection.