Milwaukee 3670-20 Grinder Review
Our verdict
The Milwaukee 3670-20 earns a near-perfect 4.9-star rating from 107 owners and weighs only 16 ounces, making it an exceptionally well-reviewed lightweight cordless grinder for professionals and serious DIYers willing to pay $189.
Check price on AmazonBest for
Professionals and skilled DIYers who prioritize a lightweight premium cordless grinder on the Milwaukee 18V M18 battery platform
Skip if
You are not invested in the Milwaukee M18 battery ecosystem or your budget caps out well below $189
- Power Source Lithium Ion Battery
- Voltage 18
- Speed 9000 RPM
- Motor 156 watts
- Weight 16 ounces
- Priced 92% above the category median ($98.50 across 92 tracked models)
Our scorecard
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Owner rating4.9/5
4.9 average across 107 owner ratings
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Popularity0.8/5
107 owner reviews, fewer than most models here
The overall score is owner satisfaction weighted by how many reviews back it, so a high rating from few reviews counts for less. The bars below show where this model stands against the other power tools and workshop machinery we track in this category on price, popularity and size. Context, not marks against it, and our read of the data, not a lab test.
Overview
The Milwaukee 3670-20 is an 18-volt lithium-ion powered angle grinder, part of Milwaukee's M18 battery platform. At 16 ounces, the listed weight makes it remarkably light for a cordless grinder, a characteristic that benefits tradespeople working overhead or in confined spaces for extended periods.
The 3670-20 runs at 9000 RPM no-load and draws 156 watts from the battery. That combination is calibrated for control and precision rather than brute-force removal, fitting use cases like pipe fitting, finish grinding, and light metal prep where finesse matters. The 4.9-star average from 107 verified purchasers is among the highest ratings in this entire category.
At $189, this is a premium investment among angle grinders. However, the Milwaukee brand reputation, M18 battery compatibility, and exceptional owner satisfaction rate justify the price for buyers already in the Milwaukee ecosystem. With 200 units sold last month, it maintains healthy demand at its price tier.
Pros
- 4.9-star rating from 107 reviews is the highest in this category segment
- 16-ounce weight is exceptionally light for an 18V cordless grinder
- Part of the Milwaukee M18 platform for battery sharing across tools
- 9000 RPM no-load speed suits precision grinding and finishing work
- 200 units sold last month confirm active demand at the premium price
Cons
- $189 price requires Milwaukee M18 battery investment to make sense
- 156-watt motor output is modest, limiting heavy material removal tasks
- Tool-only listing means additional cost if M18 batteries are not already owned
Specifications
| Power Source | Lithium Ion Battery |
|---|---|
| Voltage | 18 |
| Speed | 9000 RPM |
| Motor | 156 watts |
| Weight | 16 ounces |
Performance notes
Lithium-ion battery powered at 18 volts with a 156-watt motor and 9000 RPM no-load speed. Weighs 16 ounces, exceptionally light for the cordless grinder category. Designed for controlled precision tasks: pipe fitting, finish grinding, light prep work rather than aggressive bulk removal.
What buyers say
The Milwaukee 3670-20 earns a 4.9-star average from 107 reviews, a standout rating in its category. Owners most frequently cite the light weight and build quality as the key differentiators. Buyers note the price requires commitment to the M18 platform, but those already in the ecosystem view it as a worthwhile specialized tool.
Similar power tools and workshop machinery to consider
Frequently asked questions
Does the Milwaukee 3670-20 come with a battery?
The 3670-20 designation typically indicates a tool-only listing without battery or charger. Confirm with the current product listing, and note it requires an M18 battery to operate.
How light is the Milwaukee 3670-20 compared to other cordless grinders?
The listed weight is 16 ounces, which is significantly lighter than most cordless grinders in this category. That weight advantage is notable for overhead work or all-day use.
Have questions about Milwaukee grinders or the M18 platform?
Contact the ToolGalaxy team at hello@toolgalaxy.com.