Milwaukee 2780-20 M18 FUEL Lithium-Ion 4-1/2 in./5 in. Paddle Switch Grinder (Tool Only)

Model: miln2780-20
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Milwaukee 2780-20 M18 FUEL Lithium-Ion 4-1/2 in./5 in. Paddle Switch Grinder (Tool Only) Model: miln2780-20
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Product Features & specs :

Milwaukee 2780-20 M18 FUEL Lithium-Ion 4-1/2 in./5 in. Paddle Switch Grinder (Tool Only)

The world's first cordless grinder delivers the power of a corded grinder with up to 2X more run time and up to 10X longer motor life. The M18 FUEL 4-1/2 in. / 5 in. Grinder supplies maximum sustained power to complete the toughest grinding, surface preparation and cutting applications. The POWERSTATE Brushless Motor provides up to 10X longer motor life and lower cost of ownership. The M18 REDLITHIUM XC5.0 Battery Pack (not included) delivers up to 4X more run time and 20% more power. The grinder features REDLINK PLUS Intelligence, the most advanced system of cordless power tool electronics, for maximum performance. The 18V lithium-ion grinder's thin body design gives it optimized balance to rest easily in your hands. Tool-free accessory changes and guard adjustments mean less downtime during work. The grinder is built with the same tool body, gearing system and anti-vibration side handle as Milwaukee's legendary high-performance corded grinders for maximum durability on the job. Grinding wheel sold separately.
  • POWERSTATE Brushless Motor: Delivers maximum power and up to 10X longer motor life
  • REDLINK PLUS Intelligence provides optimized performance, electronic clutch, and overload protection using total system communication between tool, battery and charger
  • REDLITHIUM XC5.0 Battery Pack (not included) provides superior pack construction, electronics, and performance to deliver 2X more run-time and more work over pack life
  • POWER TO GRIND: World's first cordless grinder with corded performance
  • DURABILITY: Same metal housing & gearing system as legendary high performance corded grinders
  • 100% tool free: Make all accessory changes and guard adjustments without a wrench for increased productivity
  • Paddle-switch design: Provides increased comfort and ease-of-use when operating in various positions
What’s Included:
  • M18 FUEL Lithium-Ion 4-1/2 in./5 in. Paddle Switch Grinder -2780-20
  • Tool Only - Batteries and Charger Sold Separately
15 in.
3.27 in.
8.58 in.
5.8 lbs.
Arbor Size
5/8 in - 11 in
Batteries Included
Battery System
Battery Type
Bluetooth Compatibility
CSA Safety
Case Included
Charger Included
ETL Safety
Motor Type
No-Load Speed (RPM)
Power Source
Spindle Thread
5/8 in - 11 in
Switch Settings
Switch Type
UL Safety
Variable Speed
Wheel Diameter
4-1/2 in / 5 in
Wifi compatibility

Reviews :

4.7 / 5.0
428 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Would you recommend this product?
Yes (40)
Easy To Use (37)
Powerful (35)
Ergonomic Design (31)
Value (9)
Heavy (1)
Short Run Time (if applicable) (1)
Best Uses
Frequent Use (11)
Small Projects (11)
Jobsite (10)
Home Repair (8)
Lots of power!
This grinder has lots of power. It is light and very smooth!
March 22, 2020
Originally posted at
It's always in me
No cords! A really handy tool to have. I would say it's worth every penny.
March 21, 2020
Originally posted at
Milwaukee delivered again, another awesome tool
Rebuild a utility trailer, had to do about of cutting and grinding. Worked great!!!
March 21, 2020
Originally posted at
Excellent tools
I purchased a used zero turn mower and needed to do a complete refurbishment of the deck. My son recommended that I get an impact wrench an an angle grinder to make the job easier. Both worked great and certainly add the job go quicker and easier. The Milwaukee line is awesome and the feel and good looks great. Certainly two great additions to my tool chest! Thanks
March 21, 2020
Originally posted at
Love this tool!
I’m a sheet metal worker and use it to do the duct work in new homes. Love this tool!
March 21, 2020
Originally posted at
Awsome Grinder
Has just as much power as my plug in grinder, but no cords to drag around. Love it!
March 21, 2020
Originally posted at
Powerful Grinder
Runs like a corded Grinder without the cord. Run time is better with 8, 9, or 12 amp batteries.
March 21, 2020
Originally posted at
The convenience of not having a cord
I do a lot of handrails and the convenience of not pulling a cord out for using the grinder is great. The grinder has lots of power and the card on it with the preset locks in different positions makes it so I want to keep the guard on the only thing I wish the paddle switch had was a lock but it’s not a dealbreaker because I like the power switch better than the slide and locking switch.
March 21, 2020
Originally posted at
Good review
It just does what ask of it, nice not having a cord
March 21, 2020
Originally posted at
My favorite grinder
I have 2 dewalt electric grinders and a makita grinder but i would choose my m18 fuel grinder over them everyday. Its amazing how great it works for everything
March 17, 2020
Originally posted at

Q & A :

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Browse 10 questions Browse 10 questions and 12 answers
Is this compatable with the HD9.0 battery?
Jimmy S on May 29, 2019
BEST ANSWER: It is compatible with any M18 Milwaukee battery. The heavier 9.0 battery could make it a "handful," affecting the balance of the grinder.
Will this work with a normal 18v battery or does it have to be the XC 4.0
Ross on Dec 23, 2014
BEST ANSWER: The grinder will work with any M18 series battery
if these are so good how come they have recondition ones already ?
A shopper on Sep 29, 2018
BEST ANSWER: Your question will be best answered by the manufacturer, who can provide you with the accurate information. The number to reach the technician directly is 1-800-729-3878 or online at
Does it come with a case or bag?
A shopper on Aug 17, 2018
BEST ANSWER: The item will not include any case or bag.
You said milwaukee has a 5 year warranty i bought my milwaukee grinder 8 months ago it stopped working can I send it to y'all warehouse and get a replacement or how will that work? thank you
chino on Sep 13, 2017
BEST ANSWER: Milwaukee warranties will need to be handled through the manufacturer directly. They can be reached at 800-729-3878. From there you will be referenced to a service center in your area
What is the warranty on this item?
waylon on Dec 10, 2015
BEST ANSWER: Milwaukee offers a 5 year warranty on this tool.
I bought this tool to use on a log home sanding large pillar logs.

Where can I find/buy the accessories to do the job? Sanding disks, backing pad, spindle, disc nut, etc??
Thanks for the help
Rod on Sep 16, 2014
BEST ANSWER: Please contact the manufacturer direct at 1-800-729-3878 for a service/parts center in your area.
where can I find the flange nut kit for the milwaukee 18volt cordless grinder?
A shopper on Apr 20, 2018