DEWALT Grinding Wheel, Double Row, Diamond Cup, 4-1/2-Inch (DW4774)

I use this cup wheel on a very regular basis and it is awesome for cleaning and correcting masonry openings for new door and window installs. Cuts very aggressively yet leaves a nice finish. I have used my wheel hundreds of times on commercial projects and it still works great. I bought an identical replacement today because I am guessing mine will eventually die or perhaps it has slowly dulled a bit over the years without me noticing, but truth be told I can keep using my old one if I want to. Rebar does not kill it. Heat does not kill it. Hard pressure does not kill it. Caulk and paint do not clog it up. Double row is not a gimmick, it really removes a lot of material and it also helps keep you flat so you do not gouge. If your time is money, then this is the cup wheel for you. Works great on good cordless grinders too (Milwaukee for me)

Worked great

I want to write a review because the reviews other people wrote were so helpful to me when I was searching for this product.There are photos to show you what I'm working with. I have exposed foundation on every side of my house, but the south side is clearly the most exposed. The parging (as I learned it was called) is a thin layer of concrete put on as aesthetic, but also to seal cracks and protect the foundation. Well, the bottom half of the south side's parging has been broken and peeling off since I moved in 4 years ago. The rest of the parging around the house is also broken and separating from the foundation, but not as exposed.My first attempt was with a small sledge and a chisel. Well, that only got me so far. My second attempt was a 4.5 diamond blade, which worked well for giving me some diamond cuts to loosen the parging. Then I was searching for a grinding wheel for concrete, and I discovered this thing. Wow!I spent about 2-3 hours grinding this afternoon--you can see where I ground as opposed to where there was no parging. I wore earplugs, eye protection, a respirator, and a bandana. I still had to wash my hair twice and I'm still, as of tonight, getting dirt out of my ears. This grinding blade took a hit, but it is still kicking! You can see from the pics that the outer most edges wore down; but, again, that's with 2-3 hours of grinding down sometimes 1/4" - 1/2" of a large swath of concrete.Take this thing seriously. It is a very tough blade and deserves respect. Use precaution and wet your surface. It is tempting to grind without wetting the surface and when you are going it's not very fun to stop to hose the concrete. However, the dust produced is absolutely alarming.Good luck grinding. This thing is a champ!

Concrete fades to dust,Grinding wheel spins fast, precise,Stone yields in moments.

We recently had to replace about a thousand square feet of outdoor tile on a concrete slab. We had done a similar project two years ago on an adjacent area, so knowing what we were getting into, we bought several wheels to help remove the old thin set. We used a new DeWalt 13amp grinder with all of them. On the previous project we used the "4 inch Diamond Segment Grinding Cup Wheel Disc Grinder Concrete Granite Stone" (blue disc) at just over eleven dollars and it worked well and lasted for about 350 square feet. We decided that this time we would try several to see if we could get more square footage out of a blade or more importantly, if we could work less hard to remove the material (i.e. we hoped another blade would be more aggressive and reduce the effort needed). Following are all of the blades including the one this review is attached to. We hope this breakdown will help.DeWalt DW4774 4-1/2" Double Row:.This blade seemed to be the best of the bunch, but at thirty-five dollars, we question whether or not it was noticeably superior enough to justify the cost. As to durability, we finished the last 200 square feet of the project with this blade and it was still going strong which might be the justification for the price.OCR 4" Concrete Turbo Diamond Grinding Cup Wheel Three Row....:This wheel did very well and for the lower priced group lasted just shy of the 4" Diamond Segment Grinding Cup Wheel Disc... (Blue version).It ultimately lasted for about 300 square feet.4" Diamond Segment Grinding Cup Wheel Disc... (Blue version):We liked this one the best of the inexpensive group (and have ordered extras). It consistently got about 350 square feet and seemed to wear out evenly. A really good buy for the dollar.Whirlwind USA GPST 4.5" Heavy Duty Grinding Cup Wheel:This was the most expensive of the group and at first we were very disappointed in it. After using it for a while though, we came to realize it is better suited for polishing work rather than fast removal of large amounts of material. It did not seem to wear much at all for the work it did and we will look forward to using it when we need to provide a smooth finished surface. For just grinding, don't pay the high price, it is definitely not worth it.4" Diamond Segment Double Row Grinding Cup Wheel Disc.... (Black Version):This was the least competent of the bunch. It worked reasonably well but only lasted for about 200 square feet. At the end, it literally lost all of its teeth and was just a smooth flat wheel. The others in the twelve dollar range were much better buys.In summary, we feel that if you are only going to grind a smaller area of concrete (or like material) and it is not a massive project like ours, the inexpensive blades are a great buy and do just as good a job, if not better.

So far, this has performed very well. I am grinding down high spots on my concrete slab in order to install bamboo flooring. I bought this instead of the 7" because of the high cost for the cup and a shroud for my larger 7" Wildcat grinder. It will take more time but I have more time than money. So far, I have used it for a couple of hours on hard concrete and there is still yellow paint on some of the teeth! So I think it will last quite a number of hours.If you use one of these, you will want to use a shroud and shop vac because there will be a lot of dust. One thing I liked about this is that the holes for scavenging dust are larger than some of the cheaper versions and if you keep your vacuum filter clean and/or use a dust capturing system, almost no dust escapes.This tool is designed to be used flat against the surface of whatever you are grinding so it is ideal for leveling high spots. If you tilt it, it will gouge into the concrete and be harder to control. It is not for cutting. Dewalt makes another "Turbo" version that is more aggressive but for thinset, paint or light concrete grinding, this tool is more than sufficient if used properly.