3/8 Inch or 3/4 Inch Impact Wrenches? Compared by Specs
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Choosing between a 38 inch vs 34 inch impact wrench depends on your specific fastening needs. Both tools are cordless brushless models designed for durability and power. The Milwaukee M18 FUEL and the DEWALT 20V MAX XR share a similar compact design philosophy. However, their drive sizes differ significantly. This change affects the types of sockets and the maximum torque each tool can handle. You need to match the chuck size to your typical hardware.
Key differences
| Aspect | Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench | DEWALT 20V MAX XR 3/4-Inch Brushless Impact Wrench |
|---|---|---|
| Chuck Size | 3/8 inch | 3/4 inch |
| Max Torque | 250 ft-lbs | 1420 ft-lbs fastening, 1900 ft-lbs breakaway |
| Anvil Type | Friction ring | Hog ring |
| Voltage | M18 battery system | 20V MAX |
| Weight | not listed | 9.04 pounds |
Which one should you choose?
Choose Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench if
- You need access to tight spaces with a compact 4.8-inch length.
- You are working on automotive or light-duty tasks requiring precise control.
- You want a tool with four speed modes for better torque management.
Choose DEWALT 20V MAX XR 3/4-Inch Brushless Impact Wrench if
- You need high torque for heavy-duty truck or agricultural equipment.
- You require a hog ring anvil for larger socket retention.
- You work in harsh environments and need oil-resistant housing.
Verdict: The Milwaukee M18 FUEL is ideal for precision work and tight spaces where 250 ft-lbs of torque is sufficient. The DEWALT 20V MAX XR is built for heavy industrial applications requiring massive breakaway power. Select the tool that matches the drive size of your existing sockets and the torque demands of your projects.
3/8 Inch vs 3/4 Inch Impact Wrench Specs
Chuck Size
The Milwaukee M18 FUEL features a 3/8-inch drive size, which is standard for general automotive and light industrial tasks. This size accommodates a wide range of sockets and accessories commonly found in home garages. In contrast, the DEWALT 20V MAX XR uses a robust 3/4-inch drive. This larger interface is designed for heavy-duty applications, such as truck maintenance or large agricultural equipment. The 3/4-inch anvil accepts bigger sockets and handles significantly higher torque loads without risk of failure. You must choose the drive size that matches your existing socket inventory and the scale of your typical projects.
Max Torque
Torque output defines the tool's ability to loosen or tighten fasteners. The Milwaukee M18 FUEL delivers up to 250 ft-lbs of nut-busting torque. This level of power is sufficient for most car lug nuts and general mechanical work. The DEWALT 20V MAX XR offers a massive 1420 ft-lbs of max fastening torque and 1900 ft-lbs of breakaway torque. This represents a substantial increase in power, allowing you to tackle stubborn, rusted bolts on heavy machinery. If you work with large vehicles or industrial equipment, the DEWALT provides the necessary force, while the Milwaukee is optimized for lighter loads.
Motor Type
Both tools utilize brushless motor technology, which is a key specification for modern cordless impact wrenches. Brushless motors eliminate carbon brushes, reducing friction and wear. This design typically results in longer motor life, improved efficiency, and more runtime per battery charge. The Milwaukee M18 FUEL uses a POWERSTATE Brushless motor to achieve its performance metrics. The DEWALT 20V MAX XR also employs a brushless motor to drive its high-torque output. Since both manufacturers have included this advanced motor type, you get similar benefits regarding durability and heat management from either tool.
Speed Settings
Control modes allow you to adjust the tool's behavior for different tasks. The Milwaukee M18 FUEL includes a 4-Mode DRIVE CONTROL system. This offers pre-set RPM and IPM levels, including an auto shut-off mode for hand-tight applications to prevent overtightening. The DEWALT 20V MAX XR provides 3 speed settings plus a precision wrench mode. This mode helps prevent fastener run-off and overtightening during delicate work. Both tools offer multiple settings to adapt to various fastening scenarios. The Milwaukee offers one additional mode, providing slightly more granular control options for different torque requirements.
Build and Design
Physical dimensions and build materials affect handling and durability. The Milwaukee M18 FUEL is noted for its compact design, measuring just 4.8 inches in length. This short body provides unmatched access in tight spaces under hoods or in machinery. It also features tri-LEDs for enhanced visibility. The DEWALT 20V MAX XR is larger, with a length of 10.7 inches and a width of 4.5 inches. Its housing is oil-resistant, designed to combat damage from oil, grease, and solvents in harsh environments. You should prioritize the Milwaukee for confined spaces and the DEWALT for rugged, dirty job sites.
Which Impact Wrench Suits Your Needs
Mechanics needing precision in tight spaces
The Milwaukee M18 FUEL measures just 4.8 inches in length, allowing access to confined areas where larger tools fail. Its 4-mode DRIVE CONTROL lets you select specific RPM and IPM levels for delicate work. The auto shut-off mode limits torque to 20 ft-lbs, preventing overtightening on sensitive fasteners during hand-tight applications. This level of control is essential for detailed automotive repairs.
Professionals handling heavy-duty fasteners
The DEWALT 20V MAX XR delivers 1420 ft-lbs of fastening torque and 1900 ft-lbs of breakaway torque, making it ideal for tough jobs. Its 3/4-inch hog ring anvil accepts larger sockets for heavy industrial tasks. The tool resists damage from oil, grease, and solvents, ensuring durability in harsh environments. This power output handles applications that smaller wrenches cannot manage.
Users preferring compact and lightweight design
Weighing significantly less than the DEWALT option, the Milwaukee M18 FUEL offers a compact profile with a 6-inch width and 4-inch height. Its tri-LEDs provide enhanced visibility around the anvil, reducing shadows during operation. The brushless motor ensures efficient power delivery without the bulk of larger tools. This makes it easier to maneuver in crowded engine bays or tight structural spaces.
Quick picks
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench | fastening in tight or confined work spaces | Check price of Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench on Amazon |
| 2 | DEWALT 20V MAX XR 3/4-Inch Brushless Impact Wrench | High-torque industrial fastening tasks | Check price of DEWALT 20V MAX XR 3/4-Inch Brushless Impact Wrench on Amazon |
The products compared
Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench
Best for: fastening in tight or confined work spaces
- Chuck Size
- 3/8 Inch (what this guide is about)
- Max Torque
- 250 ft-lbs
- Drive Size
- 3/8"
- Motor Type
- Brushless
- Battery Included
- Bare Tool Only
- Speed Settings
- 4-Mode
View on Amazon: Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench Affiliate link
This cordless impact wrench gives you a 3/8-inch drive anvil with a friction ring and a brushless motor. It measures 4.8 inches in length, making it suitable for tight workspaces. You get up to 250 foot-pounds of nut-busting torque and four drive modes, including an auto shut-off mode. It suits you if you need compact access rather than high-torque fastening.
Pros
- Compact 4.8-inch tool length fits narrow clearances
- Delivers up to 250 ft-lbs of nut-busting torque
- Four-mode drive control includes a 20 ft-lb auto shut-off setting
- Tri-LED lighting surrounds the anvil
Cons
- Bare tool only; battery and charger are not included
- Torque ceiling of 250 ft-lbs is lower than 3/4-inch high-torque options
Good fit if
- You work in tight quarters that require a 4.8-inch tool body.
- You want pre-set speed modes and an auto shut-off function to prevent overtightening.
- You already own compatible batteries and need only a bare tool.
Skip if
- You require more than 250 ft-lbs of torque for large-diameter fasteners.
- You need a bundled battery and charger to get started.
Verdict: Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench suits mechanics and assemblers who prioritize tight-space clearance and controlled fastening over heavy-duty breaking power.
DEWALT 20V MAX XR 3/4-Inch Brushless Impact Wrench
Best for: High-torque industrial fastening tasks
- Chuck Size
- 3/4 Inch (what this guide is about)
- Drive Size
- 3/4 in.
- Power Source
- Cordless
- Motor Type
- Brushless
- Voltage
- 20V MAX
- Battery Included
- Tool only
View on Amazon: DEWALT 20V MAX XR 3/4-Inch Brushless Impact Wrench Affiliate link
This DEWALT 3/4 inch impact wrench delivers 1420 ft-lbs of fastening torque and 1900 ft-lbs of breakaway torque. It features a brushless motor and three speed settings with a precision mode to prevent overtightening. The tool is designed for tough applications and includes an oil-resistant housing. You get the wrench body only, so you will need a compatible battery and charger for operation.
Pros
- 1420 ft-lbs max fastening torque
- 1900 ft-lbs max breakaway torque
- Brushless motor for efficiency
- Three speed settings plus precision mode
- Oil-resistant tool housing
Cons
- Sold as a bare tool without battery
- Heavy at 9.04 pounds
- Long at 10.7 inches
Good fit if
- You need high torque for heavy-duty fastening
- You already own DEWALT 20V MAX batteries
- You work in environments with oil or grease
Skip if
- You want a lightweight tool for overhead use
- You prefer a 3/8 inch drive size
- You do not have compatible batteries
Verdict: DEWALT 20V MAX XR 3/4 Inch Impact Wrench is built for users who require maximum torque and durability in harsh conditions. It suits professionals who already have the battery platform and need reliable performance for large fasteners.
Specifications side by side
| Spec | Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench | DEWALT 20V MAX XR 3/4-Inch Brushless Impact Wrench |
|---|---|---|
| Max Torque | 250 ft-lbs | not stated |
| Drive Size | 3/8" | 3/4 in. |
| Power Source | not stated | Cordless |
| Motor Type | Brushless | Brushless |
| Voltage | not stated | 20V MAX |
| Battery Included | Bare Tool Only | Tool only |
| Speed Settings | 4-Mode | 3 speed settings, precision wrench mode |
| Anvil Type | Friction Ring | Hog ring |
| Included Tools | Impact Wrench | Impact Wrench |
| Chuck Size | 3/8 Inch | 3/4 Inch |
| Dimensions | 10 × 6 × 4 inches | 10.7 × 4.5 × 11.1 inches |
| Weight | 2.71 pounds | 9.04 pounds |
| Color | Black | Black, Yellow |
| Model | B08P3SRT5P | DCF964B |
| Size | not stated | One Size |
Frequently asked questions
Can a 3/8 inch impact wrench handle lug nuts?
Yes, the Milwaukee M18 FUEL 3/8-Inch Compact Impact Wrench is well-suited for automotive tasks, including lug nuts. Its compact design, measuring 10 inches in length, allows you to reach confined spaces easily. This makes it ideal for mechanics who need precision and control rather than brute force for heavy-duty breaking applications.
What is the weight difference between these models?
The DEWALT 20V MAX XR 3/4-Inch model weighs 9.04 pounds. The Milwaukee M18 FUEL is significantly lighter and more compact, measuring 10 inches long by 6 inches wide. The DEWALT unit is built for durability in harsh conditions, while the Milwaukee prioritizes ease of use in tight spots.
Which tool is better for tight spaces?
The Milwaukee M18 FUEL is the better choice for tight spaces. It features a compact design with a length of 10 inches and a width of 6 inches. This form factor allows you to access confined work areas where larger tools cannot fit, making it ideal for assemblers and detailed mechanical work.
Does the 3/4 inch wrench come with a battery?
No, the DEWALT 20V MAX XR 3/4-Inch Brushless Impact Wrench is sold as a bare tool. It does not include a battery. You will need to use it with an existing compatible battery from the DEWALT 20V MAX platform to operate it for your high-torque industrial fastening tasks.
Is the DEWALT model brushless?
Yes, the DEWALT 20V MAX XR 3/4-Inch Impact Wrench features a brushless motor. This motor type contributes to its durability and performance in harsh conditions. It is designed for professionals who require maximum torque and reliable performance for large fasteners without the maintenance associated with brushed motors.
What drive size does the Milwaukee tool use?
The Milwaukee M18 FUEL uses a 3/8-inch chuck size. This standard drive size accommodates a wide range of sockets and accessories. It is suitable for general automotive and light industrial tasks where controlled fastening is more important than heavy-duty breaking power, offering versatility for various home garage projects.
Which wrench is heavier, the Milwaukee or DEWALT?
The DEWALT 20V MAX XR is heavier at 9.04 pounds. The Milwaukee M18 FUEL is designed to be compact, with dimensions of 10 inches in length and 6 inches in width. The DEWALT unit is built for heavy industrial tasks, while the Milwaukee focuses on maneuverability in confined spaces.
Can I use the DEWALT for general automotive work?
The DEWALT 20V MAX XR is built for high-torque industrial tasks and large fasteners. While it can handle automotive work, its 3/4-inch chuck size and 9.04-pound weight make it less suitable for tight spaces compared to the Milwaukee M18 FUEL. It is best for users needing maximum durability and power.