Ryobi 18-Volt ONE+ 4-1/2 in. Angle Grinder (Tool-Only)-P421 - The Home Depot


Model # P421

Internet # 100519983

Store SKU # 152332

18-Volt ONE+ 4-1/2 in. Angle Grinder (Tool-Only)

Ryobi 18-Volt ONE+ 4-1/2 in. Angle Grinder (Tool-Only)

This item has been discontinued.
The Home Depot no longer carries this specific product.

$39.97 / each
  • Over 50 great ONE+™ tools work with the same 18V battery platform
  • Any 18V ONE+™ blue or green tool works with any 18V ONE+™ battery
  • Up to 6,500 RPMs enable fast and precise work


Model # P421

Internet # 100519983

Store SKU # 152332

The RYOBI 18-Volt ONE+ 4-1/2 in. Angle Grinder offers cordless convenience and the power of 6500 RPM for fast and precise work. This tool offers a host of user-friendly features, such as onboard wrench storage, a comfortable overmolded grip and a 3-position side handle to help reduce fatigue. It also has an intuitive trigger switch.

California residents: see  Proposition 65 information

Info & Guides

You will need Adobe® Acrobat® Reader to view PDF documents. Download a free copy from the Adobe Web site.


Assembled Depth (in.)  13.7 in  Assembled Height (in.)  5.443 in 
Assembled Width (in.)  5.669 in  Product Depth (in.)  13.701 
Product Height (in.)  5.443  Product Width (in.)  5.669 
Wheel Diameter (in.)  4.5 in 
Amperage (amps)  Arbor Size  5/8 x 11 UNC 
Batteries Included  No  Battery Power Type  Lithium Ion 
Battery Size  Lithium Ion  Charger Included  No 
Color Family  Green  Cordless Tool Type  Angle Grinder 
Cordless/Corded  Cordless  Grinding Wheel Included  Yes 
Maximum Speed (rpm)  6500  Power Tool Product Type  Cordless 
Product Weight (lb.)  6.18 lb  Reconditioned  No 
Returnable  90-Day  Side Handle  Yes 
Spindle Lock  Yes  Tools Product Type  Power Tool 
Variable Speed  No  Voltage (volts)  18 
Warranty / Certifications
Certifications and Listings  1-UL Listed  Manufacturer Warranty  3 Year Limited Warranty 


Rated 4.3 out of 5 by 91 reviewers.
Rated 4.0 out of 5.0 by Handy grinder I have used this grinder to sharpen my lawnmower blade wihout removing it from the lawnmower and it did a good job. I have also installed a steel cut off blade to cut through metal closet door hardware and it worked great. December 26, 2008
Rated 4.0 out of 5.0 by Good tool for smaller jobs I have been using this tool to open up some cracks in my garage floor in order to fill them and resurface the floor. The tool is great and does its job with a decent diamond blade. However you NEED to buy the high capacity battery for it or else you only get about 5-10 minutes of real working time. Good tool, but chews up battery quick. For bigger jobs a corded tool is better, or dish out the cash for a high capacity battery. May 7, 2014
Rated 5.0 out of 5.0 by High quality and unexpensive RYOBI cordless tools get proffesional work done I have been doing commercial HVAC since mid 2010 and I have used this grinder ever since. The grinder is not as fast as my corded Dewalt. But, in reality, no cordless grinder is going to be as fast as a corded one (regardless of brand name). However, this cordless RYOBI grinder gets the job done. It's supposed to be a DO-IT-YOURSELFER tool, but as a professional HVAC installer, I have used this grinder for professional uses. I have built ductwork in new hospitals, schools, apartment buildings, and super stores (a couple WALMARTS). I would recommend this Ryobi grinder (and any other Ryobi cordless tool) to DO-IT-YOURSELFERS and professionals as well. January 28, 2014
Rated 5.0 out of 5.0 by 18 volt angle grinder i really like the features on this angle grinder. The guard rotates without being removed and the grinder has plenty of power. October 29, 2014
Rated 5.0 out of 5.0 by Ryobi 18 Volt 4 1/2" angle grinder This is an outstanding tool. Not having to contend with cords and the ability to use it anywhere is great. I've used it with both the Lithium-Ion and the Ni-Cad batteries and it works best with the lithium because they deliver full power right up to the time they go dead, whereas the Ni-Cad will gradually slow down to the point where you're just wasting your time. I have several of the Ryobi 18 Volt tools and really like the ability to use one battery for all of them. I would like to see Ryobi develop a one or two gallon CANISTER vacuum cleaner that uses the same battery. April 8, 2015
Rated 5.0 out of 5.0 by Great little grinder. I've used grindes a lot. I use to be a TIG welder back in the '70s and used a grinder a few hours every working day back then and still use them regularly these days. I've used this grinder maybe 20 times so far and ad usual with Ryobi its a great value. So far its had plenty of power ( using the 2x Lion batt ) seems well put together, the trigger and safty work welln easy to swap disc's and I love the lt green color of these tools, makes them easy to see on the job or in the box. I buy tools that are a good value for my regular use, Ryobi over the past 10 years has earned my first consideration when I'm shopping for a new tool. October 1, 2013
Rated 5.0 out of 5.0 by works great Great tool. And in my line of work being cordless is pure freedom and a money maker. RYOBI keeps surprising me with the tools and the power of them, they keep coming out with. April 17, 2015
Rated 5.0 out of 5.0 by Best bang for buck I use this for taking off paint and preping heavy metals and it works fantastically. How ever it isnt a corded grinder replacement. I also recommend the 4.0 batteries because it will consume the short packs in minutes. February 5, 2015
  • 2015-04-23T14:00:44.108-05:00
  • bvseo_lps, prod_bvrr, vn_prr_5.6
  • cp-1, bvpage1
  • co-hasreviews, tv_91, tr_91
  • loc_en_US, sid_100519983, prod, sort_default
2 3 4 >>


Standard Shipping includes delivery by small parcel service. Processing time varies by product.

Orders for this item may be expedited for an additional fee.

Other Delivery Options:

Express and Expedited shipping options are also available. Estimated arrival times are available in checkout.

If product is eligible for shipping to AK, HI and US Territories additional transit time and remote surcharges may apply.