Milwaukee Cobalt Drill Bit

Drilling through hard metals can be a challenging task, requiring precision, durability, and reliability from your tools. Recently, I had the opportunity to put the Milwaukee Cobalt Drill Bit (model 48-89-2327) to the test in various applications, and the experience was enlightening.

Design and Build Quality

The Milwaukee Cobalt Drill Bit is designed with several features aimed at enhancing its performance and longevity. The bit is constructed from a cobalt alloy, which is known for its durability and heat resistance. This makes it a suitable choice for drilling through hard metals, stainless steel, and even PVC and wood.

One of the standout features is the 135° split point tip, which is designed to prevent walking and ensure precise starts. This is particularly useful when working on materials where accuracy is crucial. Additionally, the variable helix design aids in effective material extraction, reducing heat buildup and improving drilling efficiency.

The bit also features a 3-Flat Secure-Grip™ shank, which is intended to prevent slipping in the chuck. This is a thoughtful addition, especially when working with high-torque applications where bit slippage can be a common issue.

Performance

My first test involved drilling through a 1/8” steel plate. I was impressed by how the bit handled the task. The 135° split point tip ensured that the bit did not wander, and I was able to drill precise holes exactly where I needed them. The variable helix design seemed to work as advertised, as I noticed minimal heat buildup even after drilling multiple holes. The bit produced clean, consistent holes with long metal spirals, indicating efficient material removal.

Encouraged by these results, I decided to test the bit on a piece of 3/16” thick hardened steel. This is where the bit truly shined. Despite the hardness of the material, the bit maintained its sharpness and drilled through with relative ease. I used cutting oil to aid the process, which I believe contributed to the bit’s longevity and performance.

However, when I attempted to drill through a piece of stainless steel, the results were mixed. While the bit initially performed well, I noticed a significant drop in efficiency after a few holes. The bit started to produce smaller chips, and the drilling speed slowed down considerably. It seemed that the bit was losing its edge quicker than expected, which was disappointing given the initial performance.

Durability

Durability is where the Milwaukee Cobalt Drill Bit had some inconsistencies. In my experience, the bit held up well during the initial stages of use. The cobalt alloy construction and the variable helix design seemed to contribute to its durability. However, prolonged use on harder materials like stainless steel and cast iron showed that the bit’s edge retention was not as robust as I had hoped.

For example, I used the bit to drill multiple holes in a 1/4” thick steel angle. Initially, the bit performed admirably, but after about ten holes, I noticed a decline in its cutting efficiency. The bit started to produce triangular holes, indicating that the teeth were losing their sharpness. This was somewhat expected, as drilling through hard metals can be taxing on any bit, but it was still a point of concern.

Practicality and Ease of Use

The Milwaukee Cobalt Drill Bit is user-friendly, especially for those who are familiar with proper drilling techniques. The 3-Flat Secure-Grip™ shank ensures that the bit stays securely in the chuck, reducing the risk of slippage. This is particularly beneficial when using hand drills, as it provides more control and stability.

The bit’s design also makes it versatile for different applications. I used it to drill through wood and PVC, and it performed exceptionally well in these materials. The bit produced clean, precise holes with minimal effort, making it a reliable choice for various DIY projects.

Value for Money

The Milwaukee Cobalt Drill Bit is priced higher than some of its competitors, which raises the question of whether it offers good value for money. Based on my experience, the bit’s performance in hard metals and its initial sharpness justify the price to some extent. However, the decline in performance after extended use on harder materials like stainless steel and cast iron is a drawback.

Final Thoughts

In conclusion, the Milwaukee Cobalt Drill Bit has several strengths, including its initial sharpness, precision, and user-friendly design. It performs exceptionally well in softer metals, wood, and PVC, making it a versatile tool for various applications. However, its durability and edge retention in harder materials like stainless steel and cast iron leave room for improvement.

Would I recommend the Milwaukee Cobalt Drill Bit? Yes, but with some reservations. If your primary need is to drill through softer metals, wood, or PVC, this bit will serve you well. Its design features and initial performance make it a reliable choice for these applications. However, if you frequently work with harder materials like stainless steel, you might want to consider other options or be prepared to replace the bit more frequently.

Overall, the Milwaukee Cobalt Drill Bit is a solid tool with some limitations. Its strengths make it a worthwhile addition to your toolkit, but its performance in harder materials should be taken into account when making your purchase decision.