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Model #R86042B

Store SKU #1003910929

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18V OCTANE Brushless Cordless 4-1/2 in. Angle Grinder (Tool Only)

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  • High Power Output with 10,000 RPM
  • Includes: Spanner Wrench, Grinding Wheel and Auxiliary Handle
  • Free Parts and Service for Life with Registration
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Product Overview

RIDGID introduces the 18V OCTANE Brushless Cordless 4-1/2 in. Angle Grinder (Tool-Only). The Brushless 4-1/2 in. Angle Grinder delivers unmatched performance in a cordless package. This grinder delivers an industry leading 10,000 RPM. OCTANE tools utilize high performance brushless motors for increased power and runtime. State of the art OCTANE electronics are built to handle maximum power from OCTANE batteries. Backed by the Industry Leading Lifetime Service Agreement, the 18V OCTANE Brushless Cordless 4-1/2 in. Angle Grinder includes a spanner wrench, a grinding wheel, an auxiliary handle and an operator's manual. Battery and charger are sold separately.
  • LED Overload Indicator helps extend motor life
  • Tool Free Guard Design: Easily change the position of the guard for increased productivity
  • 3-position auxiliary handle provides optimal control and versatility on the jobsite
  • Ergonomic slim grip for maximum comfort during extended use
  • Lock-Off Protection: Prevents accidental start. If the battery is installed while the tool lock is on, the tool will not operate.
  • Hex Grip allows for easier control during use
  • 100% Compatible: Works with all RIDGID 18V Batteries and Chargers
  • Lifetime Service Agreement with registration within 90 days of purchase
  • Includes: (1) R86042 18V OCTANE Brushless 4-1/2 in. Angle Grinder, (1) spanner wrench, (1) grinding wheel, (1) auxiliary handle and operator's manual
  • Battery and charger sold separately
  • RIDGID: Build for a Lifetime

  • Click here for more information on Electronic Recycling Programs
  • California residents

Info & Guides

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Name7 Amp 4-1/2 in. Small Angle Grinder with 1-Touch Guard18V OCTANE Brushless Cordless 4-1/2 in. Angle Grinder (Tool Only)20-Volt MAX Cordless 4-1/2 in. to 5 in. Grinder (Tool Only)15 Amp Corded 7 in. Twist Handle Angle Grinder
Cordless/ CordedCordedCordlessCordlessCorded
Wheel Diameter (in.)4.5 in4-1/2 in4.5 in7 in
Power Tool FeaturesLock On Switch,No Tool Wheel Change,Spindle LockAdjustable Handle Position,Lock On Switch,Spindle LockAdjustable Handle PositionAdjustable Handle Position,Lock On Switch,No Tool Wheel Change,Variable Speed
Amperage (amps)7 A0.0 A0 A15 A
Voltage (volts) 18 V20 V
Battery Amp Hours No BatteryNo Battery
Motor Type BrushlessBrushed
Battery/Charger Tool OnlyTool Only
View ProductView ProductView ProductView Product



Product Depth (in.)
13.46 in
Product Height (in.)
6.06 in
Product Width (in.)
5.04 in
Wheel Diameter (in.)
4-1/2 in


Amperage (amps)
0.0 A
Arbor Size
Batteries Included
Battery Amp Hours
No Battery
Battery Power Type
Lithium Ion
Battery Size
Tool Only
Tool Only
Charger Included
Charger Not Included
Color Family
Cordless Tool Type
Angle Grinder
Cordless/ Corded
Electronic Speed Control
Grinder Switch Type
Sliding Switch
Grinding Wheels,Second Handle
Maximum Speed (rpm)
Motor Type
Number of Total Batteries Included
Power Tool Features
Adjustable Handle Position,Lock On Switch,Spindle Lock
Product Weight (lb.)
5 lb
Tools Product Type
Power Tool
Variable Speed
Voltage (volts)
18 V

Warranty / Certifications

Manufacturer Warranty
Lifetime Service Agreement with registration within 90 days of purchase

Questions & Answers

Typical questions asked about products:

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Customer Reviews

  • 4.3
    out of 1,083 reviews
  • 79% recommend this product
Filter by:
Showing 1-10 of 1,083 reviews
Battery NOT on the way!
I first thought the design was flawed as the battery was getting in the way. BUT after reading someone else's review, I found out the the entire guard can rotate in 4 different angles up to about 45° to make up for this! Instantly went from a 2* to 5* product! I also hope this helps others because this is a great tool!
    3 people found this helpful
    A tool you didn't know you needed
    I purchased this tool with a single project in mind. We were planning to install Vinyl plank flooring in our “Primary Bedroom” but naturally I wanted to try it out first. After buying a 3’’ cutting disc assortment, I tested this on door trim, #5 Rebar (⅝’’ Diameter), ½’’ PVC pipe, 7/16’’ OSB plywood and ⅛’’ Masonite Hardboard using a Ridgid 6 aH Octane battery with great success! The standard door trim was too thick to cut all the through, but it was still a clean cut. I was able to cut through the rebar with little wear and tear to the cutting disc and no stalling from the Sub-Compact, brushless motor. However, I did need to bend the rebar at the cut in order to finish cutting all the way through. Once I bent it down, I was easily able to cut the remaining ⅛’’. Cutting the rebar still made a good amount of sparks, but they are forced away from your body. The wood and plastic blade I used to cut through the OSB plywood had no issues, slow downs and did so with ease. The dust was kicked forward of the tool which kept the cutting surface free and clean of the debris. Overall, I would recommend this tool for anyone who already owns Ridgid Tools and needs to make minor cuts. Are you going to build an entire house with this tool…. No. But will you be able to complete the punch out task, do a quick remodel, avoid making an excessive trip to the saw cut station… Absolutely! Because this tool is cordless, you aren’t tied down by a cord. You can easily fit it into your tool box without adding to much bulk or weight. This will make quick jobs even faster with just as accurate cuts! Because Ridgid offers 100% compatibility on all their batteries, you do not have to worry about buying a special battery if you already own one. I will have to hand it to Ridgid on this tool, this is a tool that I didn’t know I needed until I used it.
      • Recommended
      9 people found this helpful
      This little saw really surprised me and in a good way. Even though it’s small and I did have doub...
      This little saw really surprised me and in a good way. Even though it’s small and I did have doubts at first it’s had plenty of power and actually came in much more handier than I originally thought. On a flooring job I used it to cut straight lines on some tile to transition floorings and it worked out great. I did a dry cut and it went smooth and did the job. It also works really good for those flimsy plywood’s and other 1/4 inch sheets. I was able to just cut on the ground with no problems. On metal i just cut some thin metal paneling which went good as well. Obviously this saw won’t replace a true circular saw but I definitely found uses for it and more to come. It’s pretty lightweight and made well. It’s very easy to use and the blades it came with are pretty good quality. Definitely suggest use the octane batteries and run time will go far beyond expectations. I like the shoe of it or base plate because it really does help to cut straight lines. I do home remodeling so this compact saw is right up my alley. It has plenty of power but I definitely don’t say it’s like a circular saw. Definitely would recommend it. One giant thing I really liked about this is I used it to cut acrylic sheets with ease.
      • Recommended
      5 people found this helpful
      good small radio but need improvement.
      First of the all, the whole package did not come as retail package. it is fine by me because i did not have to rip anything open. lol. the radio is light weight and easy to carry around. sound was mediocre. i think my cheap milwaukee radio (2590-20) sounds better. but for a single speaker, it does pretty good job. sound is still clear even at loudest volume. it comes with a short 3.5mm male/male cable to connect aux port. honestly, the cable is too short. for a radio that does not have compartment to store a phone, that cable is useless. the bluetooth connection is good. i played my music from youtube no problem. i did try the ridgid radio app briefly. it functions well. it gives me control of the radio while on bluetooth. it did crash once when i tried the announcement function in the app. but that function is useless. tried a few times and it doesnt work. i agreed with other review about the app. why does it need my location while connecting it? it doesnt make sense to me. charging port is slow. it can keep up with the music playing and bluetooth function but it is not fast enough. overall it is a good jobsite radio but there are some cons i want to see ridgid will implement for the next radio. - wish it comes with a power cable. - faster charging port. - an adapter or pocket that can attach to the battery for phone storage. - a handle to hang the radio.
        • Recommended
        3 people found this helpful
        A compact saw with big ambitions it easily cuts a wide range of materials with the included cutti...
        A compact saw with big ambitions it easily cuts a wide range of materials with the included cutting wheels – see video. It makes a mess too so safety gear is essential. The tool is nose heavy which helps in keeping the cutting wheel in contact with the workpiece. It is compatible with all Ridgid 18 volt batteries and does drain the batteries quite quickly. Clean cuts are easily achieved on flat materials but I need a bit more practice on cylindrical materials for sure. It made short work of neatly cutting 1/8 inch by two inch flat bar steel and glazed tile. A worthy inclusion to any toolbox.
        • Recommended
        5 people found this helpful
        First, I am a huge Ridgid fan, any company who believes in their products so much they put a life...
        First, I am a huge Ridgid fan, any company who believes in their products so much they put a life time warranty on them knows their tools are good! This addition to my collection is a great little tool, cut cleanly through PVC, drywall and just one small chip on the ceramic tile I tried it out on. It is light weight, easy to handle, not very loud, compact in size and plenty of power to cut the above items. It also cut through the metal item I tried it out on, the cut was rough and the saw bogged down pretty bad even though I was taking it very slow. The metal in the picture is aluminum. Just to do a quick rough cut on something like that it will be fine. Just not a pretty edge. It comes with on tool storage of the 4mm Allen wrench needed to do all the adjustments and to change the wheel. Wheel changing is very easy and quick, There is a small LED light to help light up your work area. Maintenance on this tools seems like it will be real easy. The topper on all of this, it will not take up a lot of room in your shop or tool box.
        • Recommended
        5 people found this helpful
        The battery doesn't last long enough to finish the job
        The battery doesn't last long enough to finish the job
        • Verified Purchase
        2 people found this helpful
        This coming from a guy that owns the m12 cut off tool
        I want to first off say I waited too long for this too that I almost stopped caring, but I guess I will write a review coming from a guy that has experience with both tools so far. As a contractor, I am always looking for multi purpose tools to help solve solutions especially in places where it requires a small tool to get the job done with a certain amount of finess and control. Now, for those who use TTi tools will know what i am about to say next, which it’s regarding the features that each brand has. The m12 cut off sounds more complete on paper, but it is mssing a variable speed.....why do you need it? At full speed, you are more likely to chip the tile you are working on. The ridgid has variable, but it’s missing dust collection which I need for cutting cement board. Ridgid decided to remove dust collection to save on cost, but it would have helped a great deal if they simply included the 3/8 arbor adapter at no extra cost. You see where i am getting at? Features are missing for the oddest reasons. When you compare performance, Ridgid does not cut out or stall like the M12, so that is a good thing. That means i can cut at full depth of the material w/o stalling it. Ridgid’s head where it houses the motor is overall smaller than the m12, but overall weight is about the same w/o the battery for each. In conclusion, you want better performance with variable speed and cleaner cut, go ridgid. If you want better dust collection, go M12. You want both features, buy both. If you ask for my honest opinion, I would pick ridgid for the variable speed control, but i wish that guide was better as it proves to be pretty useless. As for its lack of dust collection, maybe someone can create some kind of dust vac attachment like I have seen people do it. Ridgid definitely has the advatage over the M12 simply for being an 18v.
          • Recommended
          17 people found this helpful
          Example, when you buy tools is fine but if you going to have problems with same than you have problems, thay said lifetime service but if you didn't register your tool waranti doesn't work. I bought kit tool for house and didn't use it maybe 15-20 times in 11 years and battery want charge, 2009 i start to register tool but didn't finish for some reason and thay can't do anything about it, I will check how much is 2 new batteries and how much Ridgid company will lose if they send free 2 new ones.
            14 people found this helpful
            This is a decent grinder with the exception of the on and off switch. Its seems flimsy and likely...
            This is a decent grinder with the exception of the on and off switch. Its seems flimsy and likely to break. Switch design needs to change. Contact me for a better design.
              3 people found this helpful
              Showing 1-10 of 1,083 reviews