Milwaukee 3670-20 Grinder
- Grinder
- 156 watts
- Rechargeable battery
- 1 pound
- Better rated than 95%
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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How it ranks among the 150 grinders we track
4.9★ across 107 Amazon ratings, Bayesian-smoothed toward the category average.
107 Amazon ratings, weighted on a log scale so huge counts don't drown everything.
200+ bought on Amazon last month.
Brand identity, imagery, description and spec coverage.
The ProductDome score is separate from the Amazon rating shown above: it combines the Bayesian-smoothed Amazon rating with evidence volume, tracked demand, and data quality across the 150 grinders we track - how the scorecard works · full grinders data report. Confidence: medium - useful but incomplete evidence.Last refreshed Aug 4, 2026. Data-computed, not a hands-on test. Compiled by the ProductDome Research Team.
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.
Strengths and trade-offs
Drawn from this product's published specifications.
- 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 |
| Motor Power | 156 watts |
| Power Source | Rechargeable battery |
| Item Weight | 1 pound |
| Voltage | 18 volts |
| Speed | 9000 rpm |
Other MILWAUKEE grinders
How it compares
This product against the closest alternatives we track in grinders.
| Product | Amazon rating | Ratings | ProductDome score |
|---|---|---|---|
| Milwaukee 3670-20 GrinderThis product | 4.9 / 5 | 107 | 4.1 / 5 |
| DEWALT DCG413B GrinderDeWalt | 4.8 / 5 | 9,600 | 4.6 / 5 |
| AVID MW590 GrinderAVID | 4.5 / 5 | 6,100 | 4.4 / 5 |
| Makita 9557PBX1 GrinderMAKITA | 4.8 / 5 | 3,960 | 4.4 / 5 |
| CRAFTSMAN CMCG400B GrinderCraftsman | 4.7 / 5 | 2,900 | 4.4 / 5 |
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Questions about the MILWAUKEE 3670-20
Common buyer questions answered straight from the product spec data - no fluff, no "it depends".
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.