As part of our paid partnership with Home Depot, they sent along several Dewalt cordless power tools for review consideration – the new brushless random orbit sander, and a recent brushless braking grinder. Both are part of Dewalt’s growing 20V Max cordless power tool platform.
Ah, so you want to do some metal cutting or grinding? That’s where Dewalt’s braking grinder can come in.
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The Dewalt 20V Max brushless braking grinder, DCG413B, was a quiet introduction that we first posted about in 2017.
- Brushless motor
- 4-1/2″ wheel size
- 9,000 RPM
- 2-state trigger
- Brake stops wheel in 2 seconds or less on average
- Kickback brake engages when a pinch, stall, or bind-up is sensed
- Ideal for metal cutting and grinding
- Ideal for cutting bricks/pavers, concrete
The grinder is available as a kit or as a bare tool. As a bare tool, it comes with the auxiliary handle and Type 27 guard. As with many if not most cordless grinders, Type 1 guards, for use with cut-off wheels, are available separately.
I for one prefer paddle switches, which cut power when hand pressure is removed from the trigger. You push a lock out of the way and then squeeze the trigger. Take your hand off the trigger, and the tool comes to a stop. And since this is a breaking grinder, it comes to a stop in about two seconds.
With a slide-switch grinder, you have to slide the switch to the off position (or remove the battery) to turn it off. Generally, paddle switch grinders are safer to use, although some heavier users prefer slide switches, which can be less fatiguing.
I’m not a very frequent grinder, and so the arbor nut stood out to me, more so than I can comment about its runtime or power (which so far was adequate and abundant, respectively).
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I’m used to spanner wrenches which engage in two holes of an arbor nut. Dewalt’s 20V Max brushless grinder instead features an arbor nut that can be tightened by hand or a hex wrench. Frankly, it works really well, and is easier to use. Should you lose that hex wrench, you can source one elsewhere, although the included wrench is much longer than usual.
I really liked how easy and relatively quick it is to change discs and accessories. The spindle lock was easy to depress while during final tightening or initial loosening. The nut turned easily by hand, and tightening it with a hex wrench proved far easier than I thought it would.
You can tighten that by hand? Sorry, I’m a little behind the times here. The manual says:
While depressing the spindle lock button, tighten the locking flange by hand or using the wrench supplied.
So… yes, you can tighten it by hand. Loosening it might still require the hex wrench, though.
When the grinder first came in, I was hesitant. As mentioned, I don’t use grinders all that frequently, and while I knew I could put it through some testing, I wasn’t sure anything about it would standout. But, it surprised me.
(Dewalt’s FlexVolt grinder has a similar arbor and nut design, and also features a brake and kickback brake.)
It’s available as a bare tool, in a kit, and in a 2x 6.0Ah battery with bonus battery kit.
Overall, my initial hands-on impression is very positive. I love the arbor and nut design so far, and in use the grinder feels balances and well-controlled. The brake works, although it’s not as fast as the one on the FlexVolt grinder. Power doesn’t seem to be a concern at all, although I need more varied use before I can say for sure.
The only negative, at least to me, is the absence of a Type 1 guard, for use with straight cut-off wheels. But, if you mainly use grinding wheels and other accessories that require an open bottom, it’s a positive because it means you’re not paying for an accessory you might not need or even ever use.
Price: $169 for the bare tool
Buy Now(via Home Depot)
See Also(Kit with Bonus Battery via Home Depot)
A disc is NOT included with the grinder.
Why buy this grinder compared to a brushed motor model? More power, longer runtime, no brushes to replace, modern ergonomics.
Why buy this grinder compared to the FlexVolt brushless model? Smaller size if you only want to use 4-1/2″ accessories, works with more affordable 20V Max batteries.
I will be holding onto this review sample for a while so that I can continue to test it. If you have any questions, please let me know and I’ll answer them as best as I can.
Evadman
I got the brushed version of this grinder, and the hex key confused me. I thought it was a miss-pack when they packed the box. I registered the grinder on the dewalt website, then created a ticket, and they sent me a regular pinned spanner wrench to tighten the spindle. Later on, I learned the hex was for tightening the spindle nut, but I find it to be difficult to position.
The dewalt spindle’s pins are ever so slightly further apart than all my other grinders, so I couldn’t use the same wrench. In the short term, I just used the spindle nut from a dead grinder since the thread was the same pitch.
You can tighten the spindle nut by hand, but not with split-leather gloves. Hand-tightening a disk does nto make me feel very safe, even if it self-tightens with torque. A disk can shatter if it is not on the shaft correctly during spin-up to 7k RPM, and I don’t need more disks shattering in my face.
Evadman
I also have the 60v brushless version. The 60v is much more fatigue inducing due to weight. I end up using my 20v versions much more unless I have a lot of metal to remove or cutting anything over 1/8″ thick with a cutoff wheel.
Corey
I used a cutoff wheel to score a flathead interface in the brushed 20v recessed hex arbor. Swing and a miss on that one lol The demo driver flathead was a lot easier after I scored it.
jason gloekler
Anyone familiar with the braking system, ie if things need replaced over time like brushes? I just bought, but have not used, the flexvolt grinder.
Stuart
The brake is electronic. In normal use, the brake slows down discs in a way to minimize spin-off risks. In a kick-back situation, Dewalt says the tool’s “electronic brake engages with maximum force to quickly stop the wheel,” and so braking should be quicker. I haven’t tested this yet. Since it’s an electronic brake, there shouldn’t be anything to wear or replace over time.
Bob
This is a timely post for me. I just built a 12’x2’x 1/2” metal workbench. Putting two of the 72” Harbor Freight tool boxes underneath. The back and sides of the 1/2” plate has a welded on 1/4”x3” stiffener. Lots of welds to grind. Gave me a good excuse to buy this grinder and the flex volt one.
I like the grinder but with 5amp hour battery it feels about the same weight as the flex volt one with the 6amp battery. Not sure a compact battery with its shorter run time would work well here. The flex volt one seems to last longer and have more torque.
The 20v one has better ballance if you are using cut off blades as the paddle switch is closer to the blade. And ergonomics are better for this action. The 60v one seems better as a grinder vs a cutter.
When grinding down the welds we couldn’t keep up charging the batteries. I had 2amp/hr x 2 and 3amp/hr x 1 @ 60v and 5amp/hr x 4 @20v. I had one yellow fast charger and 2 of the 4amps /hr slower chargers. Now this was an extream test. Two guys grinding constantly for a few hrs. With a few more fast chargers I think we may have been able to keep up.
I do not like the lawyer trigger. I found it akward to depress the trigger saftey. I found myself distracted by it, focusing on the trigger not on my work piece. My corded grinders don’t have this. On my corded ones I unplug when changing blades. On these battery ones I unplug my battery when changing blades. Tools are set on workbench with blade up to ensure paddle switch is not activated. Especially now with the blade break this safety is unnecessary. It’s easy enough to defeat with a piece of duct tape on the trigger if one is so inclined or so I’ve been told.
All in all I like the grinders. They work especially great when welding. I had one with a with a wire wheel and one with a grinder blade. No cords to get caught in my welding wire leads.
Looks like the bare tool 20v and 60v are the same price. Lots of cutting and grinding I would go 20v. Just grinding I would go 60v. Or just buy both like I did :-).
Bill
Wow, now that’s a serious bench. A quick search tells me the top alone weighs about 500 lbs. You’ve piqued my curiosity; how did you support the top? I would imagine something along the lines of 4″x 4″x 0.25″ square tubing.
TJ
I can’t say for sure how he may have set this up, but the 72″ Series 2 can easily handle several hundred pounds on top of it. It’s designed to have a 56″ top box on it full of tools. In fact, the manual states the total load capacity being 6600 pounds!
Rick
I have the original 20v grinder. Mine came with a type 1.
Stuart
Random Trivia: Some first generation grinders were specifically described as cut-off tools because they lacked the power (and runtime?) to be used as true angle grinders, at least according to a product manager or engineer I spoke with a few years ago.
PETE
I’ve never used a wrench to tighten the lock nut. I’ve needed the wrench a handful of times to loosen it but that is usually only when the cutting disc gets bound up in a cut and it gives the grinder a yank. I don’t weld & fabricate as much as i used to but i did it regularly for a while & still get to play when the shop welder is busy with another project.
We have dewalts new corded versions. Their updates are nice.
Chance
I agree with PETE. I use grinders a lot, small cordless all the way up to large corded 9″ and everything in between and I basically never use a wrench to tighten or loosen a wheel or accessory. It’s amazingly rare that a wheel gets too tight to be able to loosen it by hand, especially with all the new electronic kickback clutches. Even the FlexVolt with all the power it has will easily loosen up after a heavy grinding session.
Bob
Yup that bench is a monster lol. Stiffenner/back splash is welded on top of plate in the rear. Back is bolted down to 3” angle iron that is bolted to steel building colums. Sides bolted down to angle that is bolted to pallet racking. Front has 3 legs supporting 1×2 heavy wall tubing. Bench top is bolted down to this.
Due to space constraints the bolts go into tapped holes in the plate. Let me tell you how fun it is to drill and tap a 1/2-13” thread into 1/2” steel plate. Only needed to do it 20 times 🙁
We didn’t want any weight on toolboxes incase they need to be moved out. Fork lift made it possible to move that plate. I sure wasnt gonna man handle it lol.
Ps im going to try finger tightening my wheels on my grinders. Sounds like reefing on it with the spanner/allen key is not needed. Always learning from this site.
james ouzts
i run several different sizes and brands of grinders. use them everyday. You should always use the wrench if it says to in the manual but I never do. If I’m putting a wire brush on one and i don’t have on thick gloves I will grab a wrench but other than that I use ont maybe a couple of times a year when something is really stuck on.
Chris
Since Stuart sent me one towards the end of 2017, I’d like to throw my two cents in if it’s ok.
First of, thanks again Stuart. I really appreciate it and am very grateful for it.
As for the grinder I love it. It’s got a great amount of power, it’s reasonably quiet (relative to my dad’s corded makita) and the brake is reasonable as well, if I recall it doesn’t stop instantly but it certainly doesn’t remain spinning for long.
I was able to clean up my mower deck with a wire cub brush so we could prep it for repainting. And it worked really well. Even bearing down on the tool it handled the wire brush with no problem. It’s comfortable to use even though I find the paddle safety lever a bit finicky. And I do notice the metal gearbox gets pretty warm after a few minutes of use. But talking to Dewalt about it they say it’s normal so I’m not worried. And one thing I wish they would have done is provide us with an anti vibration side handle instead. There’s not much vibration in the grinder but a vibration dampening side handle would defenitly be a plus.
Thanks again buddy 🙂 cheers.
Stuart
You’re welcome, and I’m glad it’s been working out well for you!
Nathan
funny I was going to ask – I had heard at one time there would never be a 20V class grinder – only a cut off tool. As it wouldn’t have the power and runtime to be a “grinder”.
which I always thought was bunk but whatever. I have a corded Dewalt and I’ve always thought I’d want the 20V cordless but once the 60V came out I sort of lust after that one. Interesting.
also I must be in the minority but I love the dewalt hex key idea and I’ve always been told over tightening grinder and especially cut off wheels leads to them coming apart. so don’t put too much on them. The idea being you crush the inside and might put a stress fracture in it.
Whiskey and Wood
On sale for $139 as of today at Acme Tools and Toolnut! Also, the flexvolt can be had bare tool for $179. Toolnut has a $25 off coupon for orders over $100 from dewalt, but for some users there will be a sales tax difference as well!
Whiskey and Wood
Apparently the Toolnut coupon doesn’t work on these because they are on sale
JoeM
Well, that answers that for both tools then. I was considering a grinder, now I know which one. And the sander was a given. I have to prep surfaces anyways.
Thanks Stuart!
Hilton
Makita have a ton of grinder models (close to 50 but I lost track recently) and they’ve had these Dewalt features for a while now. I like the soft start feature on the Makita along with the option of either paddle or switch starts. There’s also variable speed control and automatic torque & speed adjustments. Don’t forget the automatic wireless start that fires up the dust extractor and the electronic braking system.
Dewalt has some catching up to do.
Brian
Im a welder fabricator and this is my goto grinder for cut off disk because of the brake. Binding a cut off disk is easy to do and the resulting kick and potential shattering off the disk is dangerous. The brake on this grinder reduces this risk to the extent I won’t use a cut off disk in any other grinder.
More powerfthan my 7amp sorter grinders but not quite up to 11amp corded ones. I’ve found that when cutting 1/2″ thick steel I can get between 1″ – 1 1/4″ of cut per amp hour of battery.