Milwaukee 4-1/2" / 5" Grinder, Paddle Switch No-Lock

The Milwaukee 4-1/2" / 5" Grinder, Paddle Switch No-Lock, specifically the model 2780-20, is a powerhouse in the cordless grinder category. Having spent considerable time with this tool, I can confidently say that it delivers on many fronts, but there are a few areas where it could improve.

Design and Build Quality

The first thing that struck me about this grinder is its solid build. The tool feels hefty in the hand, which is a good indication of its durability. Milwaukee is known for making robust tools, and this one is no exception. The paddle switch is ergonomically designed, offering comfort during extended use. The lack of a lock-on switch might be a downside for some, but it adds a layer of safety that I appreciate, especially when working in precarious positions.

Performance

Performance is where this grinder truly shines. The brushless motor is incredibly efficient, providing power that rivals some corded models. I used it for various applications, including cutting through mild steel and grinding down welds, and it never felt underpowered. The advanced electronics, including the electronic clutch and overload protection, ensure that the grinder operates smoothly even under heavy loads.

One of the standout features is the Rapid Stop braking system. The disc stops spinning in under three seconds, which is a fantastic safety feature and a time-saver. This rapid stop allows me to set the tool down quickly without waiting for the disc to come to a complete halt.

Battery Life

Battery life is a bit of a mixed bag. When paired with Milwaukee’s 8.0AH High Output battery, the grinder performs admirably for extended periods. However, using smaller battery packs like the 5.0AH can lead to quicker battery drain, especially during heavy grinding tasks. I found that the tool performs best with the larger, high-output batteries, which can be a significant investment if you don’t already own them.

Versatility

The grinder is versatile, accommodating discs from 4-1/2" to 6". However, it only comes with a 6" guard, which means you’ll need to purchase a 4-1/2" guard separately if you plan to use smaller discs. This oversight is somewhat frustrating, especially given the tool’s price point. The tool-free accessory changes and guard adjustments are convenient, making it easy to switch between different tasks without needing additional tools.

Vibration and Noise

Milwaukee has done a commendable job in managing vibration. The anti-vibration handle is effective, making the tool more comfortable to use over long periods. Noise levels are relatively low for a grinder, which is a pleasant surprise. However, always remember to wear appropriate hearing protection when using any power tool.

Pros

• Powerful Brushless Motor: Provides performance comparable to corded grinders.
• Rapid Stop Braking System: Enhances safety and efficiency.
• Tool-Free Adjustments: Makes changing accessories and adjusting the guard quick and easy.
• Durable Build: Feels solid and well-made, typical of Milwaukee’s high standards.
• Anti-Vibration Handle: Reduces user fatigue during extended use.

Cons

• Battery Drain: Smaller battery packs drain quickly, making high-output batteries a necessity.
• Guard Limitations: Only includes a 6" guard; a 4-1/2" guard must be purchased separately.
• Weight: The tool is on the heavier side, which could be a drawback for some users.

Final Thoughts

The Milwaukee 2780-20 grinder is a robust, high-performing tool that excels in many areas. Its powerful motor, rapid stop feature, and durable build make it a valuable addition to any toolkit. However, the quick battery drain with smaller packs and the need to purchase an additional guard are points to consider.

Would I recommend this tool? Absolutely, but with some caveats. If you already own Milwaukee’s high-output batteries or are willing to invest in them, this grinder will serve you exceptionally well. Its performance and safety features are top-notch, making it suitable for both professional and serious DIY use. However, if you’re on a budget and can’t invest in the larger battery packs, you might find the runtime limitations frustrating.

Overall, the Milwaukee 2780-20 is a fantastic tool that offers excellent performance and durability, making it a worthwhile investment for those who need a reliable cordless grinder.