Milwaukee 3670-20 M18 FUEL Braking Grinder 4-1/2 to 6 Inch
- Wattage: 156 watts
- Maximum Rotational Speed: 9000 rpm
- Power Source: Rechargeable Battery
- Material Type: Metal, Plastic
Last refreshed Aug 4, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A compact M18 grinder built for detail work and light deburring rather than heavy material removal. Worth it if you already run Milwaukee 18V batteries.
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ASIN: B0DNGQL3TVModel: 3670-20Category: Power Grinders
Overview
The Milwaukee 3670-20 is a cordless grinder running on 18V lithium-ion power, spinning at 9000 RPM from a compact 156-watt motor. At just 16 ounces, it suits close, one-handed grinding and deburring work rather than heavy stock removal.
Milwaukee lists this under its grinder line, and the 156 watt motor and 16 ounce body place it well below the class of a full angle grinder built for cutting discs or heavy material removal. It reads more like a detail or die grinder meant for small bits, burrs, and touch up passes. No battery or charger specs are listed here, so confirm what ships in the box before buying into the M18 platform.
- 18V lithium-ion power source
- 9000 RPM no-load speed
- 156 watt motor
- 16 ounce weight
Who it's for
Suits anyone already on Milwaukee's M18 battery platform who needs a light, one-handed tool for detail grinding, deburring, or touch up work in tight spaces. It is not sized for cutting through thick stock or continuous heavy duty grinding.
Pros and cons
- Runs on Milwaukee's 18V lithium-ion battery platform
- Light 16 ounce body for one-handed control
- 9000 RPM speed suited to detail work
- Motor power is modest for heavy grinding tasks
- Battery and charger inclusion not specified
Performance notes
The 9000 RPM speed comes from an 18V lithium-ion pack rather than a cord, so output depends on the battery's charge and age like any cordless tool. The 156 watt motor and 16 ounce weight point to a tool sized for control and reach into tight spots, not for sustained high load grinding.
Specifications
| Brand | MILWAUKEE |
|---|---|
| Model | 3670-20 |
| Dimensions & fit | |
| Item Weight | 1 poundlower than 82% of 107 power grinders |
| Item Dimensions L X W X H | 16.8 × 7.4 × 4.1 inches |
| Capacity & performance | |
| Maximum Rotational Speed | 9000 rpmlower than 72% of 122 power grinders |
| Power & efficiency | |
| Wattage | 156 wattslower than 98% of 55 power grinders |
| Power Source | Rechargeable Battery |
| Voltage | 18 voltslower than 77% of 103 power grinders |
| Construction & materials | |
| Material Type | Metal, Plastic |
| Color | Black, Red |
| Included components | |
| Included Components | Milwaukee Electric - M18 FUEL 4-1/2-6 BRAKING GRIN |
| Warranty & support | |
| Manufacturer Warranty Description | Manufacturer Warranty |
| Other details | |
| Style Name | Angled |
| Item Type Name | Milwaukee Electric - M18 FUEL 4-1/2-6 BRAKING GRINDER PADDLE SWITCH |
Closest rivals on specs
20V Brushless Cordless Angle Grinder Kit with 35 Accessories- Voltage 18 vs 20 volts (-10%)
Variable Speed Brushless Angle Grinder for DeWalt 20V- Voltage 18 vs 20 volts (-10%)
Frequently asked questions
What is the 3670-20's rated speed?
It spins at 9000 RPM.
Is the 3670-20 a full size angle grinder?
Its 16 ounce weight and 156 watt motor point to a compact, detail-oriented tool rather than a heavy duty angle grinder.