in 2019, what’s the Best Angle Grinder for your current project? for your BUDGET? We review a wide range of portable grinders to help you make a decision that makes sense for you. When you look at the average of reviews for a product, you can quickly see if an angle grinder is worth spending your money on.
Personally, I trust in the power of the crowd and the consensus of what buying customers think about their purchase.
The angle grinders in this article are highly rated and have a strong reputation for quality. Having said that, every product will have a small percentage of defects. Even Apple has defective products. No brand is immune from defects.
Don’t magnify the 2% of reviews that are negative and extrapolate that to be the ‘average.’ Also, a very small percentage of the people who buy products actually leave a review — under 2% (depending on product). Which means, for every 1000 of products sold, only 20 people will leave a review (maybe). So, whether you’re buying an angle grinder, generator or an air conditioner look at the average. Trust the crowd, not the singular loud voice. Good advice for online reviews and life in general.
Sorry about that rant. Had to get it off of my chest. Let’s get back to — angle grinders.
From motor mechanics to building contractors and DIY enthusiasts, an angle grinder is one of those tools that most of us can’t do without. If you’re cleaning up metal work after welding, removing rust or burs from metal, or need to cut through any type of metal, stone or masonry, an angle grinder is often the best tool for the job.
Table of Contents...
Intro | Best Angle Grinder
An angle grinder is going to work harder than most other tools, even in the best of times. This means that buying the right angle grinder now, is going to prevent a lot of headaches in the future. Going for the best brands, like DeWalt, Makita, or Metabo is a safe bet. You can be sure that by paying a bit extra, you’re getting one of the best angle grinders. Of course, not everyone has the budget for a high-end angle grinder and, besides, if you’re only going to be using it occasionally and don’t need to do heavy-duty work, buying the most expensive angle grinder can be a waste of money. This is why we’ve chosen to review a broad selection of angle grinders.
By looking at the best of the best as well as some reasonably priced machines (that are still decent quality), there’s an angle grinder for everyone in this review. So if you’re a professional, looking for an angle grinder that’s going to take some serious punishment or the occasional home user, we’ve got the best angle grinder for your purposes. By giving you a thorough review of each product, you won’t have to spend hours searching for the right angle grinder, you’ll find the best tool for its price range in this review.
Well-balanced and affordable | Bosch GWS10-45P | 4.5″ Angle Grinder
Let’s take a little time to investigate what you should look for in an angle grinder. There are some basic features that every angle grinder should have, no matter what you’re paying for it. The gears that transfer the power from the motor to the cutting disk (or grinding wheels) need to be able to handle tough working conditions. Whether you’re cutting through steel or stone, there will be times when the cutting disc will get jammed and stop. When this happens, the gears need to be able to handle the torque that pushes against them, the best angle grinders have gearing systems that can take the punch.
Soft start is also a great feature, though not essential to the machine’s durability. An angle grinder starts with a lot of torque and this puts a strain on your wrists if the power is transferred in a quick burst. If you’re working with an angle grinder for long periods, you’re going to be starting and stopping it repeatedly as you work. After a few hours, this can take its toll on your wrists and forearms. Vibration is another factor that can make it tough to work with an angle grinder. Even the best angle grinders won’t totally eliminate the vibration at the handle, but soft grip handles are a big plus factor when working comfortably for long periods of time. A locking trigger switch can also make the job a lot more comfortable.
Another thing to look at, particularly if you’re cutting stone, is dust. The dust that is emitted from an angle grinder is incredibly fine and gets in everywhere. This fine dust acts like a grinding paste that will wear down the gears and other components inside the machine. The best angle grinders have great protection to prevent this from happening. A quality angle grinder will have essential working components that are carefully sealed against dust or have a system to prevent dust from entering the machine.
Metabo WEP15-150 Quick | 13.5 Amp 9,600 rpm Angle Grinder
When looking at what size angle grinder is the best for you, take some time to consider how you’re going to be using it and what you’re going to use it for. Grinding and cutting discs range from 4½” up to 9”. A large angle grinder is heavy and cumbersome to use. In most cases, these big machines are best for cutting through rock, especially thick granite pieces or brick walls. Though, I’d say that when it comes angle grinders, bigger isn’t always better. Unless you actually need the increased cutting depth of a big disc, a smaller angle grinder is not only much easier to use but also more versatile.
You’ll often be using the angle grinder in an awkward position and a light 4½” angle grinder is going to be a lot easier to maneuver. Probably the best advantage of using a smaller angle grinder is when you need to get into tight spaces. If you’ve ever worked on an old car, you’ll know how important this can be. If you’re cutting and grinding in an area that has limited access, a large disc might not be able to fit into where you’re working. Even it does get in there, you can easily snag other surfaces around where you’re working and this will cause a lot of unnecessary damage.
Your power source is something to look at. Personally, I think that pneumatic is the best but this means that you need an air compressor. Not everyone has an air compressor and it isn’t always that practical to take a compressor everywhere that you work, this makes electric angle grinders much more common. A good electric angle grinder isn’t really a substandard tool, it’s just that pneumatic is always better for high-torque equipment (like angle grinders) and they have the best power to weight ratio because they don’t have the extra weight of the electric motor.
Because pneumatic angle grinders aren’t that common, we’ll keep this review about electric machines. In this category, you have the choice of corded electric or cordless angle grinders. The pros and cons of these options are quite self-explanatory. A corded angle grinder will usually be more powerful, though, with all the improvements in technology, battery tools aren’t that far behind in terms of power. Battery-powered angle grinders are more expensive and you’re limited by the time that you get from a battery in between recharging it. However, working without the limitations of an electric cord is much easier in most cases.
There are a whole lot of other topics that need to be covered when talking about angle grinders like safety and the different types of cutting and grinding discs. We’ll go into these topics later in the article. First, let’s review our selection of the best angle grinders.
4.5 Inch Angle Grinder with Aluminum Case
- Powerful 7.5 AMP motor delivers 11,000 RPM for high output power
- Small diameter barrel grip (only 2-1/2″) for added comfort
- Labyrinth construction seals and protects the motor and bearings from dust and debris for longer tool life
- Lock-on/off feature for continuous operation
- AC/DC switch for use with alternative power source
- Protective zig-zig varnish seals the armature from dust and debris for longer tool life
- Extra large paddle switch for comfortable operation
- Thicker coil wires are wound more closely to reduce heat and energy loss
- All-ball bearing design and metal gear housing for durability
- Rotatable gear housing can be positioned every 90°
Overview | Makita 9557PBX1
The Makita 9557PBX1 is one of the high-end angle grinders that we’ll be reviewing here. This means that the price may not be the best for everyone, but in terms of features and quality, it’s right up there with the best of them. Makita is a brand that I personally consider to be one of the best when it comes to innovative and durable power tools.
A 7.5A electric motor gives you exceptional power for a 4½” angle grinder and at 11000 RPM (with no load), it performs fantastically. The Makita 9557PBX1 includes a switch that allows for both AC and DC operation, giving you the versatility of using an alternative power source.
When it comes to durability, the Makita 9557PBX1 is designed for longevity. The labyrinth design prevents dust from reaching the critical components, an important feature when designing an angle grinder that’s going to give superior performance for many years. The armature is also protected from dust, through the use of zigzag varnish. The durable design and build of the Makita doesn’t end there. The ball bearings and metal gear housing offer the best durability that you can hope for. As does the thick, closely wound coil wires that reduce heat and power loss.
Weighing only 4.5 LBS with a comfortable grip around the base of the machine (only 2½” in diameter) and a second handle that can be mounted to both sides of the machine, make the Makita 9557PBX1 a very comfortable angle grinder to use. It also has soft start, this will take a lot of stress off your hands. It has a large paddle switch with a locking mechanism for continuous power. All these features make the Makita 9557PBX1 one of the best and more comfortable angle grinders to use – even when working hard for long hours. It has safety guards for both cut off and grinding, adjusting the position of the wheel guard requires no tools. A rotating gear housing means that it can be positioned every 90°.
The Makita 9557PBX1 comes with a super tough case for storing and transporting the angle grinder and all your discs. With your purchase, you also get five discs for cutting and grinding, including a diamond blade with a turbo rim – this gives you a perfectly smooth cut and is excellent for cutting granite without chipping the surface. Finding spare parts and accessories for Makita tools is never a problem and they offer a 30-day free replacement guarantee on this product, as well as a 1-year warranty.
4-1/2-Inch 11-Amp Paddle Switch Angle Grinder
- Next Generation 11 Amp AC/DC 11,000 rpm motor provides the best power to weight/size ratio available
- Dust Ejection System ™ provides durability by ejecting damaging dust and debris particles that enter the tool
- Oversized brushes provide 2X brush life over previous model (D28402)
- Large spiral bevel gear provides long transmission life
- One-Touch ™ Guard allows for 360 degree rotation of the guard with a single action
- Quick-Change ™ Wheel Release allows tool free wheel removal without need for a wrench
- Top mounted and protected spindle lock button maximizes depth of cut without compromising durability
- Uniquely small gripping surface in this power class allows for the best comfort available in this class
- Newly designed side handle provides excellent ergonomics while oversized threading provides durability
- Auto-off brushes shut the tool down when the brushes need replacing to avoid tool damage
- Paddle switch with safety lock-off prevents accidental start up
- Matching wheel flanges allow the use of common accessories
- Weight : 6.1 lbs.
Overview | DEWALT DWE402
Choosing between DeWalt and Makita tools really comes down to personal preference or possibly the price. They are both among the best that you’ll find. When comparing the DeWalt DWE402 to the Makita 9557PBX1, I can’t say which is better. They are evenly matched when it comes to price – they cost within a few dollars of each other (depending on where you buy them). They have very similar features and both are designed for hard working conditions where durability is important.
The DeWalt DWE402 is a 4½” angle grinder with a motor that is quite a bit more powerful than most, here it beats the Makita 955PBX1 by quite a few amps. This angle grinder has an 11A electric motor that runs at 11000 RPM. The motor also features extra-large brushes and these won’t need replacing as often as most others. It also has an auto-off function that will prevent damage by switching the machine off when the brushes wear too low. Durability is enhanced by their Dust Ejection System. I wasn’t too sure how this works, so I did a little digging to find out more. The DeWalt Dust Ejection system is another one of those works of simple genius that I so love about DeWalt engineering. It uses the airflow of the cooling fan to create a vortex and this channels the dust and debris out of the bottom of the angle grinder, thereby preventing it from being sucked into the working parts.
The DeWalt DWE402 is slightly heavier than some others, but still very easy to use, it weighs 6.2 LBS. It has a comfortable grip around the body of the machine and has a second handle with left and right positions – oversized thread on the handle makes it easy to secure. The blade guard can rotate 360° and both the blade guard and wheel have a one-touch (tool-free) action. By mounting the spindle lock at the top of the angle grinder in a flush position, it won’t become damaged. The large paddle switch with a lock for continuous power is every bit as easy and comfortable to use as the Makita 955PBX1.
Although the design approach of the DeWalt DWE402 and that of the Makita rival is different, they seem to both be just as durable. A lot of care has been taken to design an angle grinder that is the best for professional, heavy-duty work. As with any DeWalt product, the DWE402 comes with one of the best warranty agreements, a 30-day money back guarantee, 1-year free service plan and a 3-year warranty. DeWalt offers the excellent dealership support that one would expect from any of the best power tool manufacturers.
Metabo WEP15-150 Quick
6-inch angle grinder
- Highest service life for extreme applications: robust, powerful angle grinder with greatest power density in its class for quick work progress
- New, patent-pending Metabo Long-life motor with up to 50% more torque and up to 20% higher overload capacity for quicker material removal and longer service life
- Tacho-Constamatic (TC)-Full Wave Electronics: fast work progress by means of constant speed under load
- Now even faster: M-Quick System for tool-free disc change at the touch of a button by means of M-Quick flange nut
- Tool-free adjustable guard; twist-proof
- Side handle Metabo VibraTech (MVT) handle vibration damping for convenient continuous operation
- Paddle switch with dead-man function: safe to operate due to an ergonomically integrated switch
- Metabo S-automatic Torque Limiting Clutch: minimises kick-back to the lowest level when the disc jams unexpectedly – for maximum user protection and swift progress
- Electronic overload protection, soft start and restart protection
- Gear housing can be mounted turned in 90° steps for left-handed operation or cutting
- Auto-stop carbon brushes to protect the motor
Overview | Metabo WEP15-150
The price tag of the Metabo WEP15-150 places it in a very different league to the others. Not many people will want to spend so much more on an angle grinder. You should take note that the Metabo WEP15-150 is a 6” angle grinder, whereas the others are 4½” machines. This alone, can’t account for the massive price difference. So why is the Metabo so much more expensive? Metabo tools are always expensive, but they usually tend to be the most durable and they use technology in a very different way to most others. As we review this model, some features are going to stand out as unique and very valuable. So if you’re prepared to pay for the best of the best, there are a few critical areas where the Metabo cannot be beaten.
The very first wow factor of the Metabo WERP15-150 is the safest angle grinder out of them all. Anyone who’s used an angle grinder knows how dangerous kickback can be. It’s the biggest hazard when using these machines. We’ve all just accepted this as being one of those things, you’ve got to be very cautious when using an angle grinder and you have to concentrate hard to ensure that you keep all your limbs intact.
Well, Metabo has found a way to make this angle grinder one of the safest with the development of the Metabo S-Clutch. This is not a new concept, Metabo has been doing it since 1966 and some other angle grinder manufacturers have tried to imitate it. If you’ve used a Metabo angle grinder, you’ll know that system really works. When the disc becomes jammed, the clutch will disengage the motor from the gear that drives the disc in an instant. This means that instead of pushing back against the force of the motor, the grinder will stop and the moment it’s able to move freely again, it will continue working as before.
The Metabo WERP15-150 uses a 900W (13.5A) electric motor. This looks like a bit of a downgrade when you consider that the DeWalt DW402 uses an 11A motor, this is a 4½” angle grinder and therefore uses a disc that’s half the size of the Metabo. Again, one has to look at the clever German engineering that goes into this machine. They claim that this motor delivers up to 50% more torque and has a 20% higher overload – but more than what? I would think that this comparison is made with regard to their previous models, without any context – this is a pretty meaningless statement. Be that as it may, there is something to be said for this motor or, actually, the electronics that control it.
Metabo has a system that they call Tacho Constamatic (TC) Full-Wave Electronics. They don’t divulge what the secret is behind this long name, but my guess is that it controls the frequency and, in doing so, they manage the sine wave. Whatever the engineering is behind this, the result is that you get almost constant power, regardless of the load. This means that the rated 9000 RPM at no load remains the same under load – really impressive stuff. When you use the Metabo WERP15-150, it will feel more powerful than the others, not less powerful.
As you cut deep into thick hard materials, the machine won’t strain and slow down. This also means that it’s not nearly as heavy as one would expect a grinder of this size to be, a smaller motor means less weight. In fact, it’s lighter than the DeWalt DW402 and only a little heavier than the Makita 9557PBX1 – the Metabo WERP15-150 weighs 5.7 LBS.
The large paddle and excellently padded grip make it superbly comfortable to use. The side handle has very little vibration – they call it Metabo Vibra Tech (MVT). The side handle can rotate 360° to allow for any working position, the gear housing can also be rotated 90°. It has soft start and restart. The safety guard has a tool-free rotation and the discs can also be changed without using a wrench. The dust is managed by using a fiber filter (similar to that in a vacuum cleaner), this is 100% effective but does require cleaning, so there’s some routine maintenance required here.
German engineering is renowned for innovative and detailed design. The Metabo WERP15-150 is certainly an example of this. The company is serious about their reputation and therefore offer exceptional service. Metabo Max Repair (MMR) means that they have set a maximum price threshold for service and repairs on their products – this means that you will never pay more than their specified maximum fee, but can pay less – depending on the nature of the repair. Their warranty is among the best – 3 years with a 30-day replacement guarantee. In order to qualify for the 3-year warranty, you’ll need to register your product on the Metabo website.
4.5″ Angle Grinder
- Powerful 6.0-amp motor – 11,000 no-load rpm for professional cutting and grinding applications
Service Minder Brush System – eliminates guesswork, stops tool when preventative maintenance is required
- Epoxy-coated field windings – provides protection against abrasive dust
- Lock-on slide switch – for extended-use applications
- Two-position side handle – angled to a natural position for maximum operator comfort
- Compact, light grinder – weighs in at only 3.75 Lbs.
- Versatile 5/8 In. to 11 inch spindle – works with a wide array of sizes
- Burst-protection guard – for additional user security
Includes: (1) 4-1/2 In. Angle Grinder, (1) Grinding Wheel Guard, (1) Auxiliary Handle, (1) Inner (Clamping) Flange, (1) Outer (Round Nut) Flange, (1) Spanner Wrench, (1) 4-1/2 In. Abrasive Grinding Wheel
Overview | Bosch 1375A
If you’re not going to be using your angle grinder for daily hard work, all the models we’ve looked are probably more expensive than what you’ll need. After all, most DIY guys will need an angle grinder for certain jobs but then it may be packed away in the garage for months before you’ll use it again. The Bosch 1375A is, very likely the best 4½” angle grinder for the occasional user – it’s very affordable and is a well-made piece of machinery for its intended working conditions.
The Bosch 1375A is powerful enough to handle any task that you’d want to accomplish with a 4½” angle grinder. It uses a 6A motor producing 11000 RPM with no load and features epoxy coated windings, making it quite durable for a light to medium-duty angle grinder.
It’s a very easy tool work with, weighing only 3.75 LBS, though the plastic housing and two position side handle don’t seem to provide much protection from vibration. The lock on slide switch is easy to use and uncomplicated.
I’ve always found Bosch tools to be among the most durable of the lower priced options. This means that, although very basic in its specifications, the Bosch 1375A is a tough little guy and is very affordable. You’ll get a 1-year warranty on this angle grinder.
DEWALT DCG413B 20V XR
Brushless 4.5″ Angle Grinder
- Brushless motor requires no brush changes.
- Brake stops wheel in 2 seconds or less on average
- Kickback Brake engages when a pinch, stall, or bind-up event is sensed and the electronic brake engages with maximum force to quickly stop the wheel, reduce the movement of the grinder and shut the grinder off.
- E-Switch Protection – When the ON/OFF trigger switch has a no-volt release function.
- In the event of a power outage or other unexpected shut down, the trigger switch will need to be cycled (turned off and then on) to restart tool.
- Two stage trigger requires two actions to activate tool.
Overview | DeWalt DCG413B 20V XR
For those of you who want cordless 4½” angle grinder with the power to match almost any corded equivalent, take a look at the DeWalt DCG413B 20V XR. Not only do you have the convenience of a battery-powered tool, but this is also a very compact and lightweight machine. Not to mention the DeWalt promise of uncompromised quality and advanced engineering.
The 850W brushless motor means that you get all the power you need – producing 9000RPM with no load. Its power output is equal to that of a 7A 120V angle grinder. This is very impressive for a 20V DC machine. The 20V MAX 5AH battery will give you excellent working time and all DeWalt tools in the 20V MAX range are compatible with the 20V/60V FlexVolt battery which will give you an even better battery time. One would usually expect a battery-powered tool to be heavier because of the weight of the battery. However, with the DeWalt DCG413B, this is not the case. It weighs only 3.75 LBS, adding to its easy and comfortable user experience.
The soft grip narrow body of the machine makes it very comfortable in terms of vibration and the side handle is just as impressive. The large trigger-style switch has a very natural position, making it easy to use, even for long periods of time. It has a safety brake that stops the wheel in the event of a kickback. This does make it much safer than many other angle grinders but doesn’t offer almost instant stopping, like you get with the Metabo S-Clutch. The safety brake on the DeWalt DCG413B 20V XR can take up to 2-seconds to engage, though this can be less. Even though it may not be the best, this is a good safety feature. It also has an E-Clutch that protects the motor from overload.
While not the biggest or most powerful angle grinder from the DeWalt stable, the DCG413 is relatively cheap – if you consider that it’s a battery-powered tool (which will always be more expensive) and it bears the prestigious DeWalt name. The advantages of buying DeWalt is not only in their reputation for delivering high-quality durable tools but also in their service and fantastic 3-year warranty, 1-year free service plan and 30-day money back guarantee.
PORTER-CABLE PC60TAG (6 Amp) / PORTER-CABLE PC60TPAG (7 Amp)
- Cast metal gear case increases jobsite durability and tool longevity
- Tool-free change guard provides fast and easy guard removal
- Spindle lock feature allows for single wrench bit changes
- 3-position side handle allows greater control in multiple positions
- Slide switch with lock-on
Difference between models :
- PORTER-CABLE PC60TAG = (6 Amp)
- PORTER-CABLE PC60TPAG = (7 Amp)
- Non locking paddle switch provides additional control by automatically shutting off if dropped
When it comes to affordable quality, the Porter-Cable PC60TAG and PC60TPAG offer incredible value for money. Though the model numbers differ slightly for the two variants, they are basically the same – the PC60TAG uses a 6A electric motor, whereas the PC60TPAG has a slightly upgraded 7A motor. They both deliver the same RPM, so the motor makes very little difference. Other than the 1A difference in the motor size, all specifications and features remain the same. I wouldn’t think that it makes too much difference which one you choose. The price difference between the 6A model and the 7A model is very small, so I can see most people preferring the slightly more powerful option for only a few dollars more.
The 6A/7A motor runs at 11000 RPM with no load, so it can handle pretty much the same type of work as the more expensive 4½” angle grinders. Even though this is a very cheap angle grinder and is more suitable for home use, it is a durable machine with a cast metal gear case. The body and 3-position side handle give you a reasonably comfortable grip and it’s easy to use with a standard trigger switch – there’s no lock on the switch for continuous running, though. It’s also a bit heavier than many other 4½” angle grinders, weighing 7.7 LBS. This isn’t a big deal because it isn’t really a heavy tool and you probably won’t feel the difference between this one and those that are a few pounds lighter.
The blade guard rotates by loosening a screw and the side handle has three threaded points for mounting – one at the top and one on either side. The disc locks with a wrench. So all the operations are done the old-fashioned way. However, changing the guard from the cut off guard to the grinding guard is made simple with a quick release (tool-free) spring-loaded clip.
The Porter cable PC60TAG/PC60TPAG are both durable angle grinders, though not the best for heavy-duty work on a daily basis. At this price, you can’t expect an industrial-grade machine. It is, however, excellent value for money and has a 1-year warranty.
4.5″ angle grinder with a case and and 5 abrasive wheels
Highly Versatile : removes casting fin, finishes various types of steel, bronze and aluminum materials and castings, grinds welded sections, sections cut by means of an acetylene torch, synthetic resins, slate, brick and marble.
- 6.2 Amp motor with 980W of max output power for though grinding jobs
- Spindle lock for quick and easy disc and accessory changes
- Left-mounted slide switch with quick-off feature for added safety
- Removable, forward-canted side handle for improved control and comfort for right and left-handed users
- Compact and lightweight at 4.0lbs for greater control and maneuverability, especially in overhead applications
- Low-profile gear case to get into the tightest areas
- Small diameter grip for a comfortable hold and reduced fatigue
The Hitachi G12SR4 is in the same price range as the Porta-Cable PC60TAG and is a very similar angle grinder. You get a small bonus with this one, this being a storage case and a range of cutting and grinding discs that come with your purchase.
This is a 730W (6A) 4½” angle grinder that runs at 10000 RPM (no load). Amazon has it down as a 980W (6.2A) machine – I’m going with the specs from the official Hitachi site. They have a more powerful 7.4A model available but it costs more. The Hitachi G12SR4 is probably the best value for money if you’re looking for an angle grinder to use around your home and in the garage.
VIDEO | Learn all about the Hitachi G12SR4
Like the other cheap angle grinders, it’s a basic machine. It has two positions for the side handle and the gripping positions are good, though probably not the best in terms of vibration. It’s a very light angle grinder, weighing only 4 LBS. This model also has a trigger lock for continuous use at the same speed.
Among the cheaper 4½” angle grinders in this review, the Hitachi could easily be the favorite amongst home users. I say this mostly because of the storage case that makes it convenient to pack away in the garage with your angle grinder, wrench and discs all in one contained unit. We all know how easily the blade locking wrench can grow legs and disappear. Hitachi angle grinders come with a 1-year warranty and all their products have a 30-day refund or replacement guarantee.
Using an Angle Grinder
Safety when using an angle grinder is of the highest importance. There aren’t many tools that present the same level of risk as an angle grinder, so take the necessary precautions.
Always use the correct disc
Your angle grinder is has a specified disc type/size that is to be used with that model, so always use the correct size disc. Using the wrong disc for the wrong purpose can result in serious injury. Discs are rated for masonry/stone or steel and you get discs that are made for cut-off or grinding applications. Always use the correct disc for the application. Many people use the side of the cutting disc as a grinding disc to clean up burs and rough edges after cutting. This is more dangerous than most people realize. When you do this, you wear down the disc and this can cause it to shatter without warning. A grinding disc is made for grinding and a cut-off disc is made for cutting.
All your cut-off discs have a mark that indicates how far into its diameter you can safely use the disc. As you use the disc it wears down toward the center and once it reaches the recommended safety mark, the disc must be discarded.
One of the biggest hazards with an angle grinder is when the disc shatters. This usually happens when the disc is pinched or snagged and can happen without warning, at any time. The safety guard is designed to protect you from flying shards when the disc shatters and must always be used. You usually have two safety guards that come with your angle grinder. One safety guard covers about 50% of the cutting disc and this is used for cut-off discs. The other guard has a narrow opening and is designed for grinding discs.
Most injuries relating to the use of an angle grinder are as a result of kickback. This happens when the cutting wheel comes to a sudden stop and the grinder is forced toward or away from the operator, depending on its rotational direction. Some angle grinders offer great protection against kickback and there are precautions that one can take to minimize the risk. Though, even with all the preventative measures in the world, kickback can happen without any warning.
The most common cause of kickback is when the cutting disc becomes pinched. This happens when the material that you’re cutting shifts or buckles and presses the two sides of the cutting width together. In other words, the normal gap that’s left by the width of the cutting disc becomes narrower and presses against the disc.
Kickback can also happen when the disc snags on a bur or a harder piece of material.
Because you can never be 100% sure of when or where kickback can occur, it’s important to maintain a firm grip on the angle grinder at all times. This means always having the side handle in the best position and holding the machine firmly in both hands. Always keep your hands as far away from the cutting wheel as you can. Position your body to keep the maximum distance between yourself and the angle grinder. This will give you the best position to correct a kickback without incurring harm.
Because kickback usually occurs as result of the material shifting while you cut it, supporting this material can help reduce the risk. If you’re cutting something that is secured (a brick wall or a panel or component that’s attached to a vehicle), the material is already in a fixed position. However, cutting loose sheets of metal or a granite slab is a different story. You’ll always be laying these pieces flat, in a horizontal position. If they are not supported correctly, the two pieces either side of your cut will begin to move independently.
One side may lift while the other drops or they can pull apart on one end closing the cutting line on the other. This movement is going to cause the material to press against the cutting disc. To prevent this from happening, or at least minimize it, you need to support the piece in four positions. Place a support block under the outer edges of the piece, this will hold the entire piece in one position. Then place supports under the piece, a few inches either side of your cutting line. This means that as you cut through the piece causing it to become two pieces, both pieces have equal support and it won’t collapse in on itself.
Trying to work too fast also increases your risk of kickback. Allow the angle grinder to move at its own pace. In other words, don’t put too much forward force on the angle grinder.
Work in accordance with the material you’re cutting
Depending on what you’re cutting, you’ll need to take the right precautions and work correctly. Firstly, remember never to cut or grind flammable material with an angle grinder. A cutting or grinding disc creates friction which, in turn, generates heat. If you use an angle grinder on materials like plastic or wood, they can easily catch fire. An angle grinder is meant for rock/masonry or metal. Each of these material types have their own set of working conditions.
Working with Metal
The main thing to remember about cutting metal is the shards of burning metal that are ejected from the cutting disc. This means that you should never work close to flammable materials when doing metal work with an angle grinder. Also, ensure that no other person or your pets can be harmed by the flying debris. Always work so that the sparks from the cutting disc fly away from you and not toward you.
Protective gear is very important when using an angle grinder. This means wearing thick leather gloves, safety boots, and eye protection. Because the noise levels from an angle grinder are in excess of 90dB, it’s recommended that you wear ear protection too.
Working with Rock or Masonry
You don’t have the same heat levels when cutting rock or masonry but you do have large heavy pieces being flung from the angle grinder and you should take the same precautions when working around pets and other people.
The main issue when using an angle grinder to cut concrete, rock or brickwork is the dust. The air becomes filled with very fine dust particles that are extremely hazardous. This means that in addition to the protective gear that you’d use when working with metal, it’s important to use a dust mask as well. If you’re working indoors, a dust mask isn’t enough and you’ll need to use a powerful extraction fan to assist in removing airborne dust from the room.
A final tip about masonry and rock cutting. Since the invention of diamond cutting discs, I never use conventional masonry discs. Diamond cutting discs are a lot more expensive but last much longer. This means that although you’re paying more for the cutting disc, your actual expense isn’t that much higher. Diamond cutting discs work much faster than conventional types and are much safer – a diamond cutting disc cannot shatter. A turbo diamond cutting disc (with a smooth edge) will give you a very smooth cut and I find them to be the best for cutting granite that chips very easily. You just need to remember that turbo discs get hotter than the diamond discs that have cutting teeth (like a circular saw). It’s always best to use water to keep the turbo disc cool, this also helps you attain a smoother cut.