Model#: MILN2780-20

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Brand new items;Full manufacturer warranty available
Manufacturer inspected, repaired and tested items; CPO 120 day money back guarantee
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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)

  • Note: Battery & Charger sold separately
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In Stock Delivered by Mon., Nov.18

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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
Power Source: Cordless
Spindle Thread: 5/8 in - 11
Switch Settings: No Lock
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
331 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Yes, I would recommend this to a friend (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)
If I need to ill buy this again
Convenient Portable Quality Grinding Tool
What more can you get from Milwaukee tools
I use it for cutting, grinding, and sanding.
October 27, 2019
Originally posted at
This is an awesome grinder. The weight is great and fits well in the hand. I bought a cheaper corded non-milwaukee grinder and it couldn't keep up. So far this grinder has blown away my expectations.
October 27, 2019
Originally posted at
I would definitely buy this again.
I use this for the national boat building competition and use a 6.0 battery it works great and has the perfect weight I also use it on many projects for work I don’t have any complaints at all
October 26, 2019
Originally posted at
Great tool
We replaced another brand of grinder with this and it is much quieter and more powerful.We cut 1.5" shielded power cable. I thought it was turning less rpm because of how smooth it is but it actually spins 2000 rpms more! Time will tell about the durability but the other Milwaukee tools have held up.
October 26, 2019
Originally posted at
Milwaukee quality.
A great grinder. I used it for buffing out scratches in my granite counter in kitchen. Worked great wet and dry.
October 26, 2019
Originally posted at
Great product would buy again
Much quieter & longer battery life than my non fuel m18 grinder
October 20, 2019
Originally posted at
Perfect for beveling PVC pipe during groundwork
Absolutely love the cordless option and power of this 4 1/2” FUEL grinder. Pure time saver in the ditch for groundwork and on the slab for rough-in to bevel PVC pipe. With a sander flap wheel on this grinder it makes short work of 4” & 6” PVC to get that perfect bevel prepping for glue & primer. And the lack of a cord makes it perfect for ditch work and in between steel studs at top out. Great tool with great power and the paddle switch is easy to manipulate as well, which is great when you want to set it down while the wheel is braking.
October 20, 2019
Originally posted at
I’ll never be without this!
I use my Milwaukee grinders for everything. I do a lot of custom tile work and it’s handy for curved cuts and large holes. Cuts effortlessly through concrete, pavers. I can’t kill it. I’ve also used it to build a frame for a 39 Ford making all the cuts on rectangular tubing. I purchased the cordless grinder to grind the joints on a chimney to get it ready to repoint. My Milwaukee corded grinder is now whining because I never take it out of the bag. I have 12, 18, and 28 volt tools. I’ll never be without any of them.
October 19, 2019
Originally posted at
Great stuff
Milwaukee makes great power tools and this grinder is a key product in my line of must need tools.
October 19, 2019
Originally posted at
A must
keep finding uses for this tool. Makes jobs that much easier.
October 19, 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 Out of Stock
Warranty: 5 Year 1 Year