Pick the Right Angle Grinder and Cut Concrete and Metal Like a Pro

Most of the time when people buy a grinder, they’re looking at the power, the price and the size. Extra features like variable speed and restart protection are nice additions, but not a necessity.

Most of the time when people buy a grinder, they’re looking at the power, the price and the size. Extra features like variable speed and restart protection are nice additions, but not a necessity.

Grinder Primer

An angle grinder is a versatile and portable solution to cutting, grinding and polishing that every contractor should have in their tool box. Remove rust. Strip off paint. Cut through concrete and metal. By fitting different attachments or wheels, an angle grinder can be used to cut, sand, polish and sharpen various materials. Which angle grinder is right for you? We asked Mike Iezzi, a product manager of concrete and metal tools in North America for Bosch. He was kind enough to share his answers below.

CE: Mike, thanks for taking the time to help us learn about angle grinders. First off, how are hand-held grinders categorized for today’s buyers? Size? Power? Style (angle, die, etc.)? Give us a brief overview of the common sizes and categories.

Iezzi: Hand-held grinders are generally grouped into two different categories: small angle grinders and large angle grinders. Small angle grinders include 4 ½-, 5- and 6-in. models, while large angle grinders encompass the 7- and 9-in. models. Besides the size of the grinder, these tools are also categorized by power, or the ampere. Grinders can range from 6 amps on the low end to 10 amps — which is more common — to even 15 amps.

CE: What are the most popular applications for handheld grinders? Polishing, smoothing and sanding surfaces? What types of surfaces?

Iezzi: Almost anywhere you see someone welding, you will see a grinder. Jobsite professionals and metal fabricators generally weld two seams together, and then they grind away the excess metal material a day or two later for a finished look. Less common use cases for handheld grinders, however, can include cutting rebar or other pieces of metal, as well as cutting concrete and stone. Some professionals use grinders to cut metal in place of a band saw. In addition to stone and concrete work, professionals also like using grinders for housing restoration in tuckpointing situations. Jobsite pros use grinders to remove old mortar in between bricks before restoring the concrete.

CE: How popular are cordless grinders? What’s the cost difference when going cordless? How long is the battery life in a cordless grinder?

Iezzi: Cordless grinders are becoming more and more relevant in the industry similar to when cordless drills were just emerging. As battery technology continues to improve, cordless grinders will get better and better. Today, however, cordless grinders are difficult to sell on a mass-production scale because the power and runtime needed in almost all grinding situations. These tools are being used for hours on end, so going cordless when professionals need this endless supply of power makes them a hard sell. Cordless grinders are really great for mobile users like plumbers, though, because they don’t generally need such a long runtime. By going cordless, you have the durability and power of a corded grinder, but you just don’t get that long grinding time.

I anticipate that cordless grinders will become much more relevant in the next five years as battery technology continues to progress. The cost difference between corded and cordless grinders is like comparing apples and oranges because there are so many different variables, like size and power. For price, it’s like comparing a $90 corded grinder to a similar $140 cordless model, including the battery. Battery life completely depends on the application at hand. Users can run for a couple hours cutting rebar throughout the day, but for actual grinding, the battery life lasts up to 20 minutes continually, which isn’t significant enough for many professional users today.

CE: What are the major purchase decisions when buying a grinder? Price, brand and size, but what else? Variable speed? Different shrouds? Various cutters and wheels?

Iezzi: Most of the time when people buy a grinder, they’re looking at power, price and size. Those are the three major things you should focus on, but the significance of each is interchangeable depending on the specific use. For example, some say the size is more important because it affects the weight, while others are okay with a less extensive grinder as long as the size and amps suit their needs. Shortly after those three components, brand loyalty comes in. Users are usually so familiar with the tools that they already own that they don’t want to change what they’re comfortable with. This would also include features like ergonomics of their existing grinders.

Extra features like variable speed and restart protection are nice additions, but not a necessity. However, one feature that is really popular right now would be paddle switches. Bosch offers a very unique solution where you can hold our grinders in the front, middle or back with its new paddle switch. A lot of consumers really like this because, depending on the user or application, grinders are held a variety of different ways.

CE: What advice would you give to someone looking to purchase a new hand-held grinder?

Iezzi: Other than looking at the power, price and size, I would focus heavily on ergonomics. Most professionals are using these grinders day in and day out, sometimes for 10 hours a day. The weight and size of the grinder will really impact whether it will become a pain to use over time or whether it will work well for the job at hand. Sometimes the heavy-duty grinders can affect your back and hands during long use cases, so try to find one that will fit your needs. I would also suggest looking into some of the tool’s additional features. Things like anti-vibration handles and non-lockable paddle switches can really help the user.

CE: What operational advice can you share about using a grinder? What techniques are the most productive? What safety practices are imperative?

Iezzi: The No. 1 thing to focus on when using a grinder is to make sure you have the proper personal protective equipment on, like gloves and glasses. We know some of the safety recommendations can hinder the user, but it’s incredibly important to make sure the guard is intact and that you’re grinding in a safe environment considering the sparks produced from using the tool. Besides safety equipment, be aware of potential kickback. If you’re working in a tight corner or close to the ground, you want to make sure the grinder doesn’t kick-back and hit something nearby.

CE: Briefly summarize your hand-held grinder line today. How many models do you currently have, what is your series called and what are some of the cool technologies and features that set you apart from the competition?

Iezzi: Bosch Power Tools of North America has close to 20 different grinder variations, from tuckpointing grinders to small and large angle grinders. We are updating our portfolio of grinders in February 2016, titled the GWS range. Bosch decided to revamp its entire line of grinders with an increased focus on the 10 amp [GWS10] and 13 amp [GWS13], made in multiple varieties like paddle switch and variable speed.

CE: How much do hand-held grinders cost? Give us a price range, if you can. How much more will you pay for cordless and other options?

Iezzi: Grinders usually cost $100, with a bare-minimum grinder starting around $70 and a high-end grinder reaching upward of $180. You’ll pay roughly $50 more for a cordless grinder when comparing it to a similar corded model.

CE: What separates a professional grinder from a consumer grinder?

Iezzi: Professional grinders are much more robust and heavy-duty than consumer grinders like a Dremel, which generally cost around $40. The main differences include the longevity of the tool, total cost and runtime.

Keith Gribbins is associate publisher of Compact Equipment.

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  • I agree, power, price, and size should always be the biggest things that you look for when choosing a compact grinder. After all, if you’re going to purchase one you want it to be able to do the job that you need to get done. A part of that is making sure that it has the necessary power to grind any metal you have.

  • Really nice post. Hey, I have a Mankita angle grinder but not satisfied with it so, I have decided to buy a new one. Would you kindly suggest me which concrete cutter angle grinder best or work?