Model#: MILN2780-20

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Brand new items;Full manufacturer warranty available
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New items with possible minor cosmetic damage; CPO 120 day money back guarantee
Returned items inspected, repaired and tested by CPO technicians; CPO 60 day money back guarantee

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

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  • Note: Battery & Charger sold separately
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Product Overview


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
  • M18 FUEL Lithium-Ion 4-1/2 in./5 in. Paddle Switch Grinder -2780-20
  • Tool Only - Batteries and Charger Sold Separately


Series: FUEL
Cordless: Yes
Length: 15 in.
Width: 3.27 in.
Height: 8.58 in.
Weight: 5.8 lbs.
Arbor Size: 5/8 in - 11
Batteries Included: 0
Battery System: M18
Battery Type: Li-Ion
Bluetooth Compatibility: No
CSA Safety: Yes
Case Included: No
Charger Included: No
ETL Safety: Yes
Motor Type: Brushless
No-Load Speed (RPM): 8500
Powered Tool Power Source: Electric - Cordless
Spindle Thread: 5/8 in - 11
Switch Settings: Dead Man
Switch Type: Paddle
UL Safety: Yes
Variable Speed: No
Voltage: 18V
Wheel Diameter: 4.5 in / 5 in
Wifi compatibility: No



4.7 / 5.0
181 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Yes, I would recommend this to a friend (37)
Easy To Use (34)
Powerful (32)
Ergonomic Design (30)
Value (7)
Heavy (1)
Short Run Time (if applicable) (1)
Best Uses
Small Projects (9)
Jobsite (9)
Frequent Use (8)
Home Repair (7)
I would buy this product again and again
Every day at work and at home around the shops s on the go at my camp site
August 12, 2019
Originally posted at
I would recommend this tool
This grinder has tons of power and feels very smooth. Only downfall is that it eats thru batteries quick! Plan on having a few charged up and ready to use if you have a decent amount of grinding to do. Overall it is another great product from Milwaukee.
August 12, 2019
Originally posted at
This is a great grinder! I recommend it!
I use this grinder for everything. Seems like I look for things to do with it. From grinding welds on my project car to cutting nails in a floor replacement project. If it's metal and this will fit in there, consider it ground down or cut off.
With the HD 12.0 battery it runs for a very long time. It's run time okay with the XC batteries just make sure you have one ready to go if you are working on a big project. It could be my batteries, they are a few years old.
Love that I am not dragging a cord out for a small project!
I have two other corded grinders that work very well. But most of the time I will grab this one over those. From my use of this tool it seems to have just as much power as a corded unit, without the cord!
If you are looking for a new grinder, and you want to be unplugged, this is the way to go!
August 12, 2019
Originally posted at
I would buy this product again in a heartbeat
We use this product in a welding facility everyday. We have 2 more of them that are 6 years old, and that have stood up very well
August 12, 2019
Originally posted at
Solid product.
Love this for it's ease of use. I am a grinder guy. I have a bunch of them. This is my 1st cordless. While it's down on RPM it is not down on it's ability to do the job. I am very pleased with it and it has done everything I've asked of it. Light weight for having a battery hanging off it, very balanced. Would recommend to anyone.
August 12, 2019
Originally posted at
Awesome tool
Love this grinder. Used it a bunch for cutting rebar already and for some small welding projects. Has a ton of power and works great. Would highly recommend
August 12, 2019
Originally posted at
Great little grinder ! Battery’s last a long time.
I’m a professional welder and use these grinders for pipe tie ins. Great grinders. I recommend Milwaukee products to all my friends.
August 12, 2019
Originally posted at
100% great quality and great power
All the power I need in a cordless tool. Great for jobs around the farm!
August 12, 2019
Originally posted at
I would definitely buy this again
I absolutely love this grinder, I am a glass man by trade and do automotive on the side. It is great for both, weather it’s grinding or cutting it works great. I only have a 5.0 battery for it so run time isn’t great but still good. Once I save up for the 12.0 battery it will be great on runtime.
August 12, 2019
Originally posted at
Great tool
Not having to find and use an extension cord is worth the money for this tool.
August 12, 2019
Originally posted at

Questions & Answers

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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

New Vs. Reconditioned

What's the difference between New and Factory-Reconditioned?

Factory-Reconditioned products have been returned to the manufacturer and are restored to like-new operating condition; they go through a rigorous testing and inspection process. Plus, they offer a significant savings vs. new.
  • Reconditioned products may have minor cosmetic blemishes or scratches that do not affect item performance.
  • Reconditioned products may not come with all of the consumables the new version comes with (bits, sanding pads/papers, cases, etc.).
  • Both come with a manufacturer warranty and are covered by our Money Back Guarantee; New is 30 days, Reconditioned is 120 days.
Condition: New Factory Reconditioned
Features: Same Same
Specs: Same Same
Includes: M18 FUEL Lithium-Ion 4-1/2 in./5 in. Paddle Switch Grinder -2780-20,
Tool Only - Batteries and Charger Sold Separately
M18 FUEL 4-1/2 in. - 5 in. Paddle Switch Grinder (Tool Only) -2780-80,
Flange Nuts,
Wheel Guard,
Spanner Wrench,
Tool Only - Batteries and Charger Sold Separately
Availability: In Stock In Stock
Warranty: 5 Year 1 Year