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Tools

Best Angle Grinder

Angle grinders were first developed for use with welding, removing weld slag, excessive weld metal, and burrs from the metal. Since them, creative users have found a myriad of other uses for angle grinders, using them for everything from creating ornamental patterns in metal to finishing concrete work.

Angle grinders are built on a 90 degree angle to provide the best possible torque and the best user control. By running the motor through a 90 degree gearbox, the grinder’s torque is increased. This helps prevent the grinder from binding up when encountering difficult spots in the work. It also makes it possible for the user’s hands to be at a comfortable position, while providing a clear view of the grinding wheel to work piece contact.

DeWalt D28402K 4-1/2" Angle Grinder

DeWalt’s entry has the most powerful motor in this class, at 10 amps. It also runs at 11,000 RPM, complete with overload protection. A trademarked Dual Ejection System ejects dust and particles that enter the tool through the air vents, helping ensure longer tool life by reducing potential damage. Like the Milwaukee, the wheel is easily changed, without tools. The spindle lock button on this one is oversized, making it easier to be sure that it engages the first time. The paddle switch on this one is easy to hold with all the fingers and comes with a padded side handle for user comfort.

Bosch AG40-85P 4-1/2-Inch Angle Grinder

The Bosch model has epoxy coated motor windings to prevent electrical shorts in case dust and chips work their way into the motor housing. This one has an 8.5 amp motor running at 11,000 RPM, and has been designed to operate off of AC or DC; a nice feature for those working remotely with a welding rig allowing them to plug the grinder right into the rig and pull power from it. The paddle switch on this one also has a lock, and is a little harder to work with than the DeWalt but it is sealed to keep dust out of the switch. One nice feature they’ve built into the Bosch AG40-85P is the tool stops working when the brushes need replacement, preventing the possibility of damage. The guard is tool free and a spindle lock is provided. However, you do need to use a wrench to change the wheel.

Makita 9557PB 4-1/2" Angle Grinder

Makita has a huge selection of all sizes of angle grinders. Amongst their small grinders, this model is the best. The 7.5 amp motor operates at 10,000 RPM in an all ball-bearing housing for long life. Like the Bosch, this one will run off of AC or DC current. The vents for the motor use a labyrinth construction, to keep dust and other particles out of the bearings and motor. A nice feature of this grinder is the extra-large, locking paddle switch, for comfortable operation. The gear housing can be rotated every 90 degrees, so you can select the angle which is most comfortable for you.

Hitachi G12SR3 4-1/2-Inch Angle Grinder

Hitachi’s grinder has a slide switch, which almost knocked it out of the list, but I decided that wasn’t fair to those who like slide switches. At 6 amps and 10,000 RPM, the motor is a bit smaller than the others and also the lightest grinder on this list at only 3.1 pounds. Add rubber over-molding on the barrel and you’ve got a high degree of operator comfort. The side handle is slightly canted towards the front, providing better leverage to the user. Hitachi has even made the brushes easily accessible for quick replacement. While replacing the five included wheels does require an included wrench, there is a spindle lock. The price on this grinder is incredible making it an attractive option for handymen everywhere.

Chicago Electric 4-1/2” Angle Grinder

While you can’t expect this budget Chicago Electric angle grinder to last as long as a Makita or Milwaukee, I’ve used one of these for several years. With the little bit of grinding I need to do when I’m welding, it seems to be adequate to the need. I’ve owned cheaper budget angle grinders from Harbor Freight but they never lasted as long as this one has. It has a paddle switch making it much easier to work with which anyone can appreciate. The six amp motor gives a maximum speed of 10,000 RPM, making it comparable with the Hitachi for power but weighs a bit more, coming in at 1.19 pounds. The kit comes with a spare set of brushes which is nice, especially since they are designed to be easy to replace.

Milwaukee 0725-21 28-Volt 4-1/2 Inch Grinder Cut-Off Tool

Milwaukee has managed to be the first tool manufacturer to break the 20 volt ceiling on angle grinders. This tool operates off of a 28 volt Lithium-Ion battery so you know it will have plenty of power when you need it. It operates at 8,000 RPM, which isn’t the fastest on this list, but fast enough to make sure it gets the job done.

The motor is electronically controlled, allowing soft starts and consistent speed, even under load. Milwaukee has put an oversized spindle lock button on this tool making wheel changing easy and convenient. It also comes with a “fuel gauge” to indicate the battery run time remaining. The kit ships with only one battery, so if you don’t have other Milwaukee M28 tools, you’ll definitely want to consider buying a spare.

Makita BGA452 18-Volt LXT Lithium-Ion Cordless 4-1/2-Inch Cut-Off/Angle Grinder Kit

I have to admit, I’m a little partial to Makita’s cordless tools. Maybe it’s because my first cordless drill oh so many years ago was manufactured by Makita. They were known for quality back then, and they still produce excellent quality tools now. This cordless angle grinder runs at 10,000 rpm, making it the fastest unit on our list meaning this extra motor speed will help you cut and grind faster. At 5.3 pounds, it’s not the lightest unit on our list but right at the middle road for weight.

As with all units in the LTX line, the high capacity battery will recharge in only 30 minutes, twice as fast as most other models. The included charger is chip controlled and has a cooling fan to extend battery life. Another nice feature about this tool is a built-in circuit which senses over-torque and will shut down the grinder to protect the device and the operator. The slender handle insures people with small hands or those wearing gloves can easily grasp and use this tool.

Porter-Cable PCC61B 20V Max Lithium Cut off/Grinder

Porter-Cable has upped the power on their cordless grinder a bit, going from 18 volts to 20 with the motor producing a very respectable 8,500 RPM for aggressive cutting of all surfaces. This tool only comes as a stand-alone unit, sans kit, battery or charger. If you are already using Porter-Cable tools, this can actually save you some money.

I really like this grinder handle which includes a knuckle protector to go with the comfortable, padded handle. A two finger switch is inside the protected area of the handle for easy tool control. There is a spindle lock on the grinder for easy wheel changes, as well as a three position side handle so you can place it where it is the most comfortable for your work style.

Dewalt 20V MAX XR Cordless Lithium-Ion Cut-Off Tool Kit

The most impressive feature about DeWalt grinder is the tool-free wheel changing system (It being one of the first I’ve ever seen with a tool-free wheel change) allowing change between  cutting and grinding wheels in seconds. The handle is also very comfortable, much like the one on the Porter-Cable, with a knuckle guard and a two-finger switch (I’d have to say it’s even more comfortable than the Porter-Cable.) By adding extra leg to the case design, DeWalt made the handle thinner, easier to grip, stronger, and added protection to the operator’s hand, good news for those of who’ve probably scraped their fingers across many a sharp piece of metal. While he motor on this grinder runs at a slower 7,000 RMP, it’s still fast enough to get the job done.

Hitachi G18DL 18-Volt 4-1/2-Inch Lithium Ion Disc Grinder

Hitachi really knows how to build convenience into their power tools. At only 4.2 pounds, this grinder is the lightest on our list and runs at 9,200 rpm, making it the second fastest model of these five picks. The side handle can be attached in either of two positions, a slide power switch with a lock button for safety and also includes over-torque protection circuitry with a safety reset. Even better, this grinder will not only take Li-Ion batteries, but all Hitachi rechargeable batteries including Li-Ion, NiCad and NiMH. The included charger will also charge all those battery types, not something commonly found with cordless tools. Finally, the carbon brushes on this unit are easily accessible for rapid repair.

Bosch 1974-8 7-Inch Large Angle Grinder

I had a hard time making the decision to switch from Bosch’s 9” angle grinder to this model but what sold me on this model is the high speed performance. The 4 HP motor in this grinder is running at 8500 RPM, a full 2000 RPM faster than the 9” unit meaning it’s taking material off faster and getting your work done quicker; quite a selling point.

The guard system has quick keyless adjustment and for maximum motor protection, the motor windings are epoxy coated so dust can’t get in them. There are also service minder brushes which stop the grinder from working when they’re worn, preventing potential motor damage. Removable brush covers make changing out brushes a snap and the trigger is designed to help prevent accidental startups, a welcome safety feature.

DEWALT DWE4517 7-Inch 8,500 Rpm 4 HP Angle Grinder

It was tough deciding between this grinder and the Bosch for first place since both have a 4 HP motor and run at 8,500 RPM. What made the difference though was the weight with the Bosch being almost a full pound lighter than this angle grinder from DeWalt. Like the Bosch, the motor armature and field windings are epoxy coated to protect against dust and abrasion along with an automatic shutdown feature for when the brushes are worn down to prevent motor damage. A brush window allows quick and easy brush changes, the guard is adjustable without a key and the side handle can be set in two different positions depending upon your needs.

Milwaukee 6088-30 7"/9" 15 Amp Large Angle Grinder

This angle grinder from Milwaukee has a 4.2 HP motor running at 6000 RPM with overload protection so there’s plenty of power for heavy jobs without risking damage to the tool. The air intake for motor cooling is built with baffles to keep dust out of the motor housing. Both handles are rubber over molded providing a soft grip. Milwaukee has also provided external brush doors making maintenance a breeze while both the 7” and 9” guards feature tool-less adjustment.

Makita GA9040S 9-Inch Angle Grinder Soft Start Technology

Makita doesn’t provide a horsepower rating for their big angle grinder but it’s a 15 AMP motor so we can safely assume it offers comparable horsepower. The motor has a “soft start” feature, for smoother start-ups; if you’ve ever used a heavy duty angle grinder they can feel like they’re tearing your arms off when they start so it’s a nice feature to have. The rear handle rotates for better ergonomics and there’s soft over molded handles making this grinder a very comfortable tool to use overall. Like our other heavy-duty grinders, the motor armature is protected from dust for longer life and the guard is easily adjustable without any tools.

Fein WSG20-230 8-Inch Grinder

Fein isn’t as well known here in the United States but this German company produces high performance, and durable tools. This grinder features a 1,250 watt motor running at 6600 RPM, actually a little less power than other grinders on our list. However, Fein has given this grinder the soft start feature we discussed with the Makita grinder, along with a rotating rear handle. The ball bearings come with dust protectors, and all electronic components are sealed.

Buyer's Guide

 

Angle Grinder Buyer's Guide

Angle grinders are one of the few handheld power tools designed primarily for metalworking. However, they’ve since been found to be useful for a variety of other purposes. Replacing the grinding wheel with different mediums allows it to be used tasks ranging from concrete finishing to removing decals from vehicles.

The angle grinder is a fairly simple tool with an electric motor run through a right-angle gearbox. The output of the gearbox then becomes the arbor for attaching the grinding wheel or other medium. By using a right-angle gearbox, the tool becomes much more ergonomic to hold onto, making it both more comfortable to use and much easier to control.

Typically, they’re held two-handed, providing excellent control. The other thing the gearbox does is reduce the chance of the tool binding up from too much of a load being placed on it.
While simple, the angle grinder is a very effective tool. When used for metalworking, it’s used predominantly used for smoothing and grinding welds, removing weld splatter, slag, and excessive weld. The high tool speed and rough grinding medium allows it to work quickly.

A variety of grinding wheels and other attachments can be connected to a grinder, each of which is designed for working with particular materials and performing particular tasks. These include grinding wheels for different materials, metal cutting wheels, wire brushes, polishing bonnets and Scotchbrite pads for cleaning and paint stripping.

Of all the handheld power tools on the market, angle grinders provide the least protection for the user. The guards on these tools are minimal and only cover the back side of the attachment, the side facing the user. It’s typical to produce a large amount of sparks when using a grinder so protective goggles and gloves should be used. It’s also important to ensure the tool has come to a complete stop before setting it down.

Selecting a Grinder Size

While there are several sizes that angle grinders are made in, they basically fall into two categories, small and large. The small ones range from 4” to 5” and the large from 7” to 9”. Smaller grinding disks can always be attached to a grinder, but larger ones can’t. It’s also important to take into consideration the maximum speed of any particular attachment.

Grinders rotate at high speed and the attachment must be able to withstand the rotational force without coming apart. These attachments typically have the max RPM stated on them to provide the user the ability to properly selecting their attachments.

While two angle grinders may have the same rotational speed, that doesn't mean they’ll provide the same amount of cutting action. A larger grinder will be moving faster at the edge, as measured in feet per second than a smaller grinder moving at the same RPM. This makes the larger grinders cut faster, giving them preference for commercial use.

This increase in cutting size means that you should pick the largest grinder that you can reasonably fit within your tool budget. That will ultimately save you time and have the tool pay for itself.

What to Look For in an Angle Grinder

Power
When selecting a grinder, power and size are the two major considerations. The higher power allows you to put more pressure on the grinder, making a bolder cut. While speed and wheel size are important factors in grinding capability, the amount of pressure placed on the point of contact with the workpiece is important as well.

Comfort
Operator comfort is also an important factor when selecting a grinder. Tool weight, adjustable handle positions and over-molded rubber handles all play a part in operator fatigue. While not usually the number one factor when selecting tools, these factors shouldn’t be ignored.

Gear Greasing
When buying inexpensive angle grinders, one of the best things you can do is to open up the gearhead and fill it with grease. The gears themselves will probably be greased, but by adding more grease you will help to cool the gears and allow them to last longer.

Brushes
Of all power tools, angle grinders go through motor brushes faster than any other. This probably has to do with the fact that when these tools are used, they’re typically on for extended periods of time. Ease of brush replacement and availability of replacement brushes are both important factors for cases where the grinder will be used a lot.

Cordless Grinders

Besides the two different size ranges of angle grinders that are available on the market, there are also cordless grinders. These are only available in the smaller size range, as the larger grinding wheel requires more power to operate.

Cordless grinders are great if you are working on a remote site, but can be a bit of a hassle in a workshop. Generally speaking, when angle grinders are in use, they are on for an extended period of time. Even though cordless angle grinders use Lithium-Ion batteries, the batteries can only power the grinder for a certain amount of time. If you’re using the grinder continually, you will probably need a total of three batteries and two chargers to keep the unit operating constantly.

Rich the Tool Man

Before embarking on the current stage of my life, I spent 15 years as a Manufacturing Engineer in both the medical equipment field (medical electronics) and automotive engineering (city transit buses). After that, I owned a small construction company, mostly doing residential remodeling and commercial tenant finishes. I am no longer in either of these fields, but still get my hands plenty dirty as a consummate do-it-yourselfer; working on everything from remodeling my own home to rebuilding my car’s engines. My hobby (when I can find the time) is woodworking; making everything from toilet paper holders, to shelves, to music stands for my own home. My wife long ago gave up the idea that a two car garage is for parking two cars; it is my workshop.

While I cannot claim to having worked professionally with all types of tools, I have worked professionally with some. This comes from my previous careers, where I had to specify, buy and at times live with those decisions. Additionally, I would have to say that my engineering background has given me a thorough understanding of the construction of such tools. So, while I may not have used a particular type of tool personally, I have the knowledge to cut through all the advertising hype and statistics; in order to get at the truth of how well a tool will operate and last.

In my current career as a writer, I've written over 90 books. This includes my own titles and those I've written on contract. I've also written a complete website on how to build your own home.

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