The Ultimate Guide to Finding the Best Cordless Angle Grinder: Unveiling the Winner

Are you tired of lugging around heavy, cumbersome tools for your DIY projects? Well, we have the solution for you - the best cordless angle grinder lineup! Say goodbye to tangled cords and hello to effortless portability. In this article, we will delve into the Ryobi 18V ONE Cordless Angle Grinder Starter Kit and explore its specifications, features, and performance. We'll also reveal the results of our rigorous testing, evaluate its ergonomics, and compare it to other angle grinders on the market. So, if you're in search of the ultimate cordless angle grinder, keep reading to find out which one takes the top spot!

Cordless Angle Grinder Lineup

To ensure that the tools in this Head-to-Head are comparable, each manufacturer was given specific parameters: a voltage range of 18-22 volts, a diameter range of 4-1/2" to 6", and battery packs ranging from 5.0 to 6.2 Ah. The following cordless angle grinders were included in the test:

1. Bosch GWS18V-45 – Bosch 18V EC Brushless Connected 4-1/2 Inch Angle Grinder with No Lock-On Paddle Switch
2. DEWALT DCG413 – DEWALT 4-1/2 Inch 20V MAX XR Paddle Switch Small Angle Grinder with Kickback Brake
3. Hilti AG 4S-A22 – Hilti AG 4S-A22 4-1/2 Inch 22V Cordless Brushless Angle Grinder with Kwik Lock
4. Makita XAG21ZU – Makita 18V Brushless Cordless 4-1/2" / 5" Paddle Switch Cut-Off/Angle Grinder with Electric Brake and AWS
5. Metabo WPB 18 LTX BL 115 – Metabo 18V 4-1/2 Inch Brushless Cordless Angle Grinder
6. Ridgid R860412 – Ridgid 18V 4-1/2 Inch Cordless Angle Grinder
7. Ryobi P423 – Ryobi 18V ONE+ Cordless Angle Grinder

Ryobi 18V ONE+ Cordless Angle Grinder Starter Kit

Best for: Starting at the very beginning

What better way to get started with angle grinding than with a complete starter kit? The Ryobi 18V ONE+ Cordless Angle Grinder Starter Kit includes an 18V grinder with a 115mm disc, no-load speed of 7500rpm, and a three-point handle for flexibility and control.

The Ryobi grinder is lightweight and designed for comfortable use. It features a tool-less blade guard to protect against dust and sparks, and a two-stage non-lockable switch for safety. The kit comes with a 4.0Ah rechargeable battery and charger, making it easy to operate and handle any task.

For beginners, the Ryobi 18V ONE+ Cordless Angle Grinder Starter Kit provides everything you need to get started in angle grinding.

Cordless Angle Grinder Specifications and Features

Bosch GWS18V-45

• Disc Diameter: 4-1/2 inches
• Weight: 6 lbs 2 oz
• Voltage: 18V
• Battery Size: 6.3 Ah
• No-load speed: 9000, 6000, 4500 RPM (push button selector)
• Unique illuminated user interface
• LED work light
• Watt-Hours (Voltage x Amp-Hours) = 113.4

DEWALT DCG413

• Disc Diameter: 4-1/2 inches
• Weight: 5 lbs 14 oz
• Voltage: 18V (20V MAX No load)
• Battery Size: 6.0 Ah
• No-load speed: 9000 RPM
• Tool-less lock nut
• Kickback Brake
• E-Switch Protection™
• Watt-Hours (Voltage x Amp-Hours) = 108.0

Hilti AG 4S-A22

• Disc Diameter: 5 inches
• Weight: 6 lbs 4 oz
• Voltage: 22V
• Battery Size: 5.2 Ah
• No-load speed: 3500-8000 RPM (six-step dial)
• Active Torque Control (ATC) stops the tool body from spinning uncontrollably if the disc jams
• Watt-Hours (Voltage x Amp-Hours) = 114.4

Makita XAG21ZU

• Disc Diameter: 4-1/2 or 5 inch
• Weight: 6 lbs 3 oz
• Voltage: 18V
• Battery Size: 6.0 Ah0
• No-load speed: 3500-8500 RPM (variable dial)
• Electric Brake
• Active Feedback-sensing Technology (AFT®)
• Automatic-start Wireless System (AWS™)
• Watt-Hours (Voltage x Amp-Hours) = 108.0

Metabo WPB 18 LTX BL 115

• Disc Diameter: 4-1/2 inches
• Weight: 6 lbs 2 oz
• Voltage: 18V
• Battery Size: 5.5 Ah
• No-load speed: 9000 RPM
• Unique rotating battery
• Tool-free adjustable guard
• Quick braking system
• Electronic safety shutdown of the motor reduces kickback
• Watt-Hours (Voltage x Amp-Hours) = 99.0

Metabo HPT G18DBAL

• Disc Diameter: 4-1/2 inches
• Weight: 5 lbs 11 oz
• Voltage: 18V
• Battery Size: 6.0 Ah
• No-load speed: 9000 RPM
• Kick-back protection
• Auto-mode option automatically adjusts the RPM down when the tool is not in use
• Watt-Hours (Voltage x Amp-Hours) = 108.0

Milwaukee 2980

• Disc Diameter: 4-1/2 to 6 inch discs
• Weight: 7 lbs 12 oz
• Voltage: 18V
• Battery Size: 6.0 Ah
• No-load speed: 9000 RPM
• Rapid Stop braking feature stops all accessories in 3 seconds or less
• Tool-free accessory changes using the FIXTEC nut and tool-free guard
• Watt-Hours (Voltage x Amp-Hours) = 108.0

Ridgid R860412

• Disc Diameter: 4-1/2 inches
• Weight: 6 lbs 3 oz
• Voltage: 18V
• Battery Size: 6.0 Ah
• No-load speed: 10,600 RPM
• Tool-Free Guard Design
• Lock-Off Protection
• Watt-Hours (Voltage x Amp-Hours) = 108.0

Ryobi P423

• Disc Diameter: 4-1/2 inches
• Weight: 6 lbs 1 oz
• Voltage: 18V
• Battery Size: 6.0 Ah
• No-load speed: 10,600 RPM
• Tool-Free Guard Design
• Watt-Hours (Voltage x Amp-Hours) = 108.0

Cordless Angle Grinder Testing Materials

To evaluate performance effectively, a variety of steel and concrete materials were used in the testing. The following materials were included:

• 5/8" rebar
• 3/8" plate steel
• 1" J-Bolts
• 1/4" thick channel stock
• Thin-set mortar applied to concrete block (CMU)

Cordless Angle Grinder Performance (Speed) Testing

Winner – Metabo WPB18LTXBL115

The next test focused on performance or speed. The time it took to cut 5/8" rebar was measured throughout the run-time testing and averaged for each tool. This provided insight into the disc speed and overall efficiency of each grinder.

As shown in the chart, Metabo came in first place, followed by Milwaukee and Ryobi. Metabo was nearly twice as fast as Ridgid.

While measuring run-time and cut speeds, the external temperature of each angle grinder was measured using a thermal imaging tool. Heat can be a concern for high-demand cordless tools like grinders. The chart below shows the maximum measured temperature for each tool during the cutting tests. Although the temperatures were not used in scoring, they provide valuable information. Metabo ran the coolest at 92 deg. F, while Makita reached the highest temperature at 125 deg. F.

Cordless Angle Grinder Run-Time Testing Results

Winner – DEWALT DCG413R2

The run-time testing focused on comparing the total available energy (watt-hours) among the grinders. By normalizing the results, it was possible to compare the tools more accurately. The watt-hours were calculated by multiplying the voltage by the amp-hour rating on the battery pack. For example, Metabo had a watt-hour rating of 99, so the results for Metabo were adjusted by approximately 9%. The results showed DEWALT had the most cuts per charge with 50, followed closely by Metabo with 49, and Hilti with 47.

Cordless Angle Grinder Ergonomics Evaluation

Winners – Hilti and Makita

The ergonomics evaluation took into account various factors such as grip, side handle, blade guard, blade guard mount, disc change, power switch, battery change, vibration, balance, maneuverability, and brake speed. Each category was ranked by the team, with 1 being the best. For brake speed, the time for the disc to come to a full stop was measured. The lowest score in each category was considered the best. Hilti and Makita tied for first place, followed by Bosch in second and Milwaukee in third.

The evaluation relied on team members using the grinders in real-world scenarios, such as grinding thin-set, grinding steel, and cutting steel, to provide a relative comparison of each tool.

Cordless Angle Grinder Testing Stations

To ensure consistent and reliable test results, we have developed testing jigs and rigs that remove human user variability. These testing stations eliminate questions about factors like applied force and cutting angle, which may affect the results. While we couldn't build a jig for every test, below are the testing stations used for this Head-to-Head comparison. The first station used a jig, while the other two stations allowed our testers to use the grinders free-hand for a more hands-on evaluation of ergonomics.

The three testing stations are as follows:

• Performance Rebar Cutting Sled: This station involved using a cutting sled to remove the human element in terms of cutting angle and pressure. The sled was designed to hold each cordless grinder with the cutting disc positioned at a 90-degree angle to the rebar. A 7 lb weight was applied during cutting to ensure consistent applied force. The sled was used for both run-time calculations and performance measurement in terms of cutting speed.

Each grinder used a new Metabo metal abrasive cut-off disc, with each disc being changed after 17 cuts.

• Removal of Thin Set from CMU Block: Testers used the cordless angle grinders to remove thin set mortar from CMU blocks using a grinding wheel. A diamond cup grinding disc with dust shrouds, attached to a Bosch HEPA vacuum, was used for this station. This station provided testers with more hands-on experience to evaluate the ergonomics of the tools.

• Steel Grinding: The crew used the cordless angle grinders to remove surface material from a steel angle. This station allowed the crew to gain more experience in grinding and polishing for further evaluation. Various discs, including cutting/grinding discs, DEWALT flap discs, Diablo diamond cutting discs, and ceramic sanding discs, were used for surface finishing, prep, and beveling steel for welding.

Angle Grinder Features Comparison

The winners in this category are Bosch and Makita. We evaluated ten different categories, which include:

• Tool-less Locking Nut
• LED Light
• Multiple Disc Sizes
• Variable Speed
• Tool-less Guard
• Battery Gauge - On-tool gauge for better visibility during use
• Bluetooth Connectivity - Remote Dust Control, Tool Customization, Tool Crib Features
• Electronic Clutch
• Drop Control
• Re-start Protection

This comparison focuses solely on the presence or absence of these features, with a score of "1" for having a feature and "0" for not having it. The tool with the highest ranking is considered the best in this category.

Stand Out Features

There are a few standout features that significantly impact performance and safety. Below, we have listed these features along with the grinders that possess them.

• Tool-less Lock Nuts: Only the DEWALT, Hilti, and Milwaukee tools come with tool-less lock nuts as standard equipment. This feature saves time and convenience. Tool-less lock nuts for Hilti and Metabo can be purchased separately but are not included by default.
• Variable Speed: The Bosch grinder features an illuminated push-button control with 3 speed settings. The Hilti has a 6-step dial, while the Makita offers a step-less dial. Variable speed control allows these tools to be used for additional tasks such as grinding stainless steel or polishing stone and ceramic surfaces.

• Battery Gauges (On the Tool for Better Visibility): The Bosch and Makita tools have battery gauges on both the tool and the battery. The Bosch even has a bright green illuminated display to show battery life. These on-board gauges provide visual indication of remaining battery charge while working, eliminating the need to pause and check the battery level.
• Rotating Battery Pack: The Metabo grinder stands out with its unique rotating battery pack, allowing for better grinding angles and access to tighter spots compared to grinders with fixed batteries.

• Safety Clutch: Many grinders are equipped with a safety clutch that shuts down the tool when the wheel binds up during cutting or grinding. The Bosch, DEWALT, Hilti, Makita, Metabo, and Metabo HPT all have a safety clutch.
• Drop Control: The Bosch distinguishes itself with the "Drop Control" feature, which automatically shuts down the tool when it is dropped.
• Re-Start Protection: All grinders, except one, include some form of re-start protection. This ensures that if a battery runs out of charge and a new pack is installed while the switch is on, the grinder won't turn on during the battery change. This provides an important safety measure that all grinders should have.
• Remote Dust Control: Makita offers a remote dust control option, known as Automatic-start Wireless System (AWS™), which utilizes Bluetooth® technology for wireless power-on/off communication between the tool and dust extractor.

The Bosch and Makita grinders tied for first place, with the Bosch earning favor due to its illuminated controls. DEWALT, Hilti, and Milwaukee tied for second place, while Metabo and Metabo HPT tied for third.

Cordless Angle Grinder Pricing Evaluation

The winner in terms of pricing is Ryobi. For this evaluation, we focused solely on the bare tool price rather than considering kit pricing or additional battery pack and charger costs. This approach allows for more consistency in comparing the prices across different manufacturers, as all of them offer bare tool pricing.

The chart below shows the pricing of each bare tool at the time of publication. There are three distinct price groups: around $100, including Ryobi, Bosch, and Ridgid; just under $200, including DEWALT, Hilti, and Metabo HPT; and over $200, including Makita, Metabo, and Milwaukee. The rankings are based solely on cost, taking into account that cost is an important factor for many users when combined with other results. Ryobi takes first place, followed by Bosch and Ridgid in second, and DEWALT in third.

Best Cordless 4-1/2" to 6" Angle Grinder Winner

The winner of Best 4-1/2" to 6" Cordless Angle Grinder is the DEWALT DCG413. In another closely contested competition, the DEWALT DCG413 emerged as the winner among the Tool Box Buzz Crew. It ranked first in run-time, tied for second in features, third in price, and fourth in ergonomics and speed. Our team found it to be a well-balanced grinder with ample power and run-time to handle any job.

Coming in a close second is the Bosch GWS18V-45, which ranked first in features, second in ergonomics and price, fifth in speed, and sixth in run-time. The new Hilti AG 4S-A22, recently introduced to the market, takes third place. It ranked first in ergonomics, tied for second in features, third in run-time, fourth in price, and seventh in speed.

Below is a summary table of the final rankings:

Overall, the cordless angle grinder lineup has proven to be a game-changer in the world of power tools. With its impressive performance, long run-time, and ergonomic design, it has undoubtedly surpassed expectations. Among the various contenders, the Ryobi 18V ONE Cordless Angle Grinder Starter Kit stood out as a clear winner. Its powerful speed, efficient run-time, and attractive pricing make it the top choice for both professionals and DIY enthusiasts alike. Whether you're a contractor working on a job site or a hobbyist tackling a home project, the best cordless 4-1/2" to 6" angle grinder is undoubtedly the Ryobi 18V ONE Cordless Angle Grinder Starter Kit.