Last Updated on October 11, 2023 by Pro Handyman Australia – Editorial Team
A Dive into Angle Grinder Basics
Angle grinders, a handy staple in every toolbox, are remarkably versatile tools that come to the rescue of both avid DIY enthusiasts and professional tradespeople. Differing little in appearance, making an informed choice when purchasing one can be somewhat challenging.
With this comprehensive guide to angle grinders, we aim to simplify your decision-making process. It offers a deep dive into the essence of angle grinders, their working mechanism, and their diverse utility. Furthermore, this guide categorizes different types of grinders and discs and provides insights into which ones are most suitable for specific tasks and materials. We will also unravel the key features and power ratings of angle grinders, delve into their safe usage, and present critical factors to consider when purchasing an angle grinder.
Unraveling the Utility of Angle Grinders
Primarily, an angle grinder is a portable power tool predominantly employed for grinding, cutting, polishing, and sanding a variety of materials. Its utility extends to a plethora of metalwork tasks, such as rust removal and adding a matte finish to glossy surfaces with wire brushes. Additionally, it is perfect for honing blades with a specialized sharpening disc.
How Does an Angle Grinder Operate?
The operation of an angle grinder is based on the high-speed rotation of a disc. The nature of the disc used determines whether it can grind, cut, polish, or sand.
Angle grinders comprise a rear handle embedded with a trigger switch, a motor and gearbox, a side handle, a disc (also referred to as a wheel or head), and an adjustable disc guard. Cordless models also incorporate a battery pack.
Significantly, the disc on an angle grinder is positioned at a 90° angle when the tool is in use (thus, its name). The disc connects to the grinder via a threaded spindle (or driver shaft) and is secured by a clamping nut that can be detached using a pin spanner.
Choosing Your Perfect Angle Grinder
The selection of an angle grinder involves careful consideration of several key factors.
The pivotal determinant is the nature of the tasks you intend to accomplish. This will dictate the size of the grinder, its power rating, portability, and maneuverability. For instance, a larger grinder accommodates bigger discs for more profound cuts compared to a smaller one. Working on dense materials calls for a high-powered grinder. When operating at a height, a cordless grinder is more convenient than a corded one.
The anticipated duration of use also plays a critical role. For prolonged usage, the grinder’s weight and power rating become important. Opt for a lightweight model with a higher power rating for faster completion of tasks. Corded angle grinders offer uninterrupted operation.
Consider also the frequency of use. If the tool will be employed infrequently for DIY tasks, you may not need as much power as a regular tradesperson would. For professionals, durability takes precedence. Finally, always keep in mind your budget.
Corded or Cordless: The Dilemma
Corded angle grinders function with a connection to the mains electricity supply, which offers limitless operation time and consistent power. They are typically lighter and more affordable than cordless models, but their requirement for proximity to a power source limits maneuverability and portability.
A variant of the corded angle grinder is the air angle grinder. Rather than using electricity, it operates on air pressure from a connected air compressor unit. These models are the lightest available, favored by metalworkers for their safety in moist environments and an instantaneous start and stop feature.
Cordless angle grinders run on rechargeable batteries, ideal for areas with no power supply or when working at heights or on scaffolding. The absence of a cord enhances work efficiency. However, they are restricted by battery capacity, are heavier, and more expensive than their corded counterparts.
Brushed or Brushless: Understanding the Difference
Brushed angle grinders are driven by small metal brushes in their motors. On the other hand, brushless angle grinders operate through an electronic circuit board and sensor in the motor. The lack of brushes in a brushless motor results in diminished friction and heat build-up, leading to less wear and tear and extending their lifespan. Brushless motors also offer improved operational efficiency compared to brushed motors.
Unveiling the Types of Angle Grinders
With a plethora of angle grinders available in the market, determining the most suitable one for your needs can indeed be perplexing. Our buying guide is here to shed light on the various types and their utilities, ensuring you make an informed choice aligning with your specific requirements.
The Compact 115mm Angle Grinder
Angle grinders with a 115mm diameter, often referred to as small angle grinders, are lightweight and easy to maneuver. Their compact size and a maximum cutting depth of 30mm make them the perfect tool for precision and finishing work. Tasks such as tile trimming, blade sharpening, and intricate stone or metalwork cutting or grinding can be executed with ease. Furthermore, these tools are suitable for deburring, sanding, and polishing, particularly in smaller areas.
Versatile 125mm Angle Grinder
Medium-sized 125mm angle grinders are your go-to tools for regular small-scale work. Equipped with a maximum cutting depth of 38mm, these grinders excel in tasks including metal and other material cutting, grinding, deburring, sanding, polishing, and sharpening.
The Power-packed 230mm Angle Grinder
The large 230mm angle grinders, although bulkier and heavier than their smaller counterparts, compensate with their powerful capabilities. Despite their slower operation due to increased power, they are often preferred in the construction industry. Their significant cutting depth of 70mm allows for easy cutting of dense metals, bricks, and masonry, and they are also useful for creating chases in walls. Furthermore, these large grinders can effectively deburr, sand, and grind down materials.
The Air-driven Angle Grinder
Air angle grinders, running on air pressure provided by an air compressor, present an alternative to electric or battery-operated models. These grinders are compact and lightweight but can be somewhat difficult to maneuver due to the attached air hose. They can accommodate varying disc sizes from 50mm (2″) to 180mm (7″), depending on the model. They are extensively utilized by welders and metalworkers for precision cutting and grinding tasks.
Exploring Other Variants of Angle Grinders
In addition to the standard angle grinders, there are some specialized variations worth considering. One such variant is the straight die grinder. While it operates similarly to a regular angle grinder, the disc in a straight die grinder is aligned in a straight line with the spindle and motor shaft, as opposed to the typical 90° angle. This unique design allows it to access difficult-to-reach areas where standard grinders might not fit.
Another specialized variant is the die grinder. Instead of employing discs, it utilizes a drill bit-like die for grinding materials. Its compact size enables it to navigate tight spaces, making it perfect for grinding materials or deburring rough metal edges.
Understanding Different Types of Angle Grinder Discs
Choosing the appropriate disc for your angle grinder is essential and, in many cases, even more critical than selecting the grinder itself, much like the importance of different types of drill bits for specific drilling tasks. Different discs are designed for different jobs, and using an inappropriate one might result in the disc shattering and causing potential injuries.
Furthermore, it’s crucial to pick the correct-sized disc for your angle grinder, considering both the diameter of the disc and the size of its bore hole – the center hole that the grinder’s spindle fits through.
To aid you in the selection process, this guide elaborates on various types of angle grinder discs and their respective uses.
Cleaning and Preparation Discs
Cleaning and preparation discs serve primarily for sanding and surface preparation tasks. Multiple types are available, such as wire discs that help remove paint, rust, and scale from metal and also clean metal and stone surfaces. Refining discs are another variant used for eliminating imperfections on metal surfaces.
Cutting Discs
These discs are designed for making quick and straight cuts in various materials, including metal, plastic, wood, concrete, stone, ceramics, and tiles. It’s crucial to select a disc that is appropriate for the material you’re working with.
Flap Discs
Constructed from overlapping pieces of an abrasive material known as zirconia alumina, flap discs are used for grinding and sanding down metal and wood, providing a smooth finish. Their flapped configuration enhances their durability, outlasting standard metal grinding discs. You can choose from various grit types to achieve the desired smoothness.
Grinding Discs
Grinding discs are used for grinding away materials or stripping paint and rust. They come in variants suited for stone or metal.
Polishing Discs
Polishing discs serve to polish and buff metal and paintwork. They come in three densities: soft, medium, or coarse, and lamb’s wool for more delicate work.
Mortar Rakes
Mortar rakes, available as discs or bits akin to a drill bit, can be directly attached to the angle grinder’s spindle. They are used to remove mortar from between bricks or masonry for tasks like repointing or weatherproofing properties.
Diamond Blades
Diamond blades are cutting blades enhanced with a high concentration of diamond for fast, long-lasting cutting. These blades are ideal for cutting tough masonry materials such as natural stone, concrete, reinforced concrete, engineering brick, and granite. Certain diamond blades are also capable of cutting metals like aluminium, stainless steel, steel, and cast iron.
Brush Cups
Brush cups are designed for cleaning and preparation tasks such as rust and paint removal.
Selecting the Right Angle Grinder and Disc for Different Materials
While a variety of blades available for angle grinders can cut through diverse materials, this guide helps you choose the best angle grinder and disc for different materials.
Cutting Wood with an Angle Grinder
Cutting wood using an angle grinder is generally discouraged due to safety concerns.
Cutting Concrete with an Angle Grinder
Concrete can be cut using an angle grinder – to a depth of 30mm with a 115mm grinder, 38mm with a 125mm grinder, and 70mm with a 230mm grinder. The most suitable disc for this job is a diamond blade, though a cutting disc could also be used.
Cutting Granite with an Angle Grinder
Granite can be cut up to a depth of 30mm using a 115mm angle grinder and up to 70mm with a 230mm angle grinder. A diamond blade is the most recommended for this task.
Cutting Tiles with an Angle Grinder
Tiles can be cut effectively with a 115mm angle grinder using either a cutting disc or a diamond blade.
Cutting Stainless Steel with an Angle Grinder
Stainless steel can be cut to a depth of 30mm with a 115mm angle grinder, 38mm with a 125mm angle grinder, and 70mm with a 230mm angle grinder using a cutting disc. A diamond blade can also be used, but only with a 115mm angle grinder.
Cutting Aluminium with an Angle Grinder
Aluminium can be cut up to a depth of 30mm with a 115mm angle grinder, 38mm with a 125mm angle grinder, and 70mm with a 230mm angle grinder using a cutting disc. A diamond blade is also an option, but only with a 115mm angle grinder.
Cutting Cast Iron with an Angle Grinder
Cast iron can be cut to a depth of 30mm using a 115mm angle grinder and a diamond blade.
Understanding Essential Angle Grinder Features
When purchasing an angle grinder, it’s crucial to be aware of the various features and functions they offer.
Spindle Lock
A spindle lock prevents the spindle from rotating while the disc is being changed, facilitating quick and easy disc removal and replacement.
Auxiliary Handle
An auxiliary handle provides additional control over the grinder. This removable handle can be attached to either side of the grinder, accommodating both right and left-handed users.
LED Light Signal
An LED light signal illuminates to warn if the grinder is overheating or if the circuit breaker is triggered.
Quick-Change Disc
Angle grinders with this feature accommodate quick-change discs, which can be twisted on and off rather than removing a clamping nut with a tool. This is particularly beneficial if you frequently switch discs.
Anti-Vibration Handle
An anti-vibration handle minimizes the amount of vibration felt through the handle, enhancing comfort, particularly for extended periods of usage.
Optimised Coolant System
This feature is crucial for prolonged usage, helping to cool down the engine and prevent overheating.
Built-In Dampening System
A built-in dampening system, located near the rear handle of the grinder, further reduces vibration.
Vacuum Attachment
This attachment allows the connection of the grinder to a vacuum, which can then suck up the debris as you cut or grind. This feature helps maintain a clean workspace and prevents the inhalation of harmful particles.
Protective Swivel Guard
Every angle grinder is equipped with a protective swivel guard. This safety feature surrounds up to half of the unused disc, preventing accidents. There are different types of guards designed for grinding or cutting tasks. For instance, a grinding guard has an open bottom, while a cutting guard is enclosed on the top, side, and bottom.
Ensuring Safety with Angle Grinders
Angle grinders are powerful and versatile tools, but they can also be dangerous without proper care and handling. Built-in safety features in these tools may vary depending on the model.
Essential Safety Features in Angle Grinders
Safety features in angle grinders could include:
- A disc guard, designed to shield the user from touching the idle side of the disc.
- A kickback brake that automatically halts the disc from spinning if it encounters resistance.
- A two-stage trigger, which requires the activation of a safety switch before the tool can be started.
- A kill switch designed to halt the disc’s rotation in under two seconds.
- A circuit breaker trigger that disconnects the power supply in the event of a power failure.
- A slow start function, which begins the rotation gradually before it attains maximum speed.
- Restart protection that inhibits the tool from restarting automatically if it has overheated or has cut out while still switched on.
- A paddle switch, also known as a “dead man’s switch,” which automatically stops the angle grinder from rotating if not held with two hands.
Safe Use of Angle Grinders
To minimize the risk of accidents while using an angle grinder, consider these safety precautions:
- Always wear protective gear such as goggles, ear defenders, gloves, and a dust mask.
- For corded angle grinders, always make sure it’s switched off before plugging it in.
- Use the right disc for the task at hand.
- Always make use of the safety guard.
- Control the angle grinder with both hands at all times.
- Avoid distractions while using the angle grinder and take regular breaks.
Prolonging the Life of Your Angle Grinder through Proper Maintenance
Careful and regular maintenance of your angle grinder can extend its life, prevent it from malfunctioning, and ensure optimal performance. Here are some simple steps to follow:
- Clean both the internal and external surfaces of the grinder before each use to ensure it’s free from dirt and debris.
- Regularly grease the gears.
- Regularly inspect the brushes in a brushed motor and replace them when worn out.
- Dispose of worn-out discs promptly to prevent accidental reuse.
- Store the angle grinder safely when not in use. For example, keep it unplugged, or with the battery detached if it’s a cordless model, and out of the reach of children. Consider using a dedicated carry case or a storage rack for safekeeping.
Essential Factors to Consider When Purchasing an Angle Grinder
When planning to buy an angle grinder, several key considerations will help guide your decision-making. These encompass factors such as intended usage, grinder size, power requirements, and speed settings.
Determining Usage Frequency and Duration
The frequency and duration of use are vital factors when considering an angle grinder purchase. If you plan on using the grinder for extended periods, an ergonomically designed model that offers a comfortable handle can be beneficial. The tool’s weight should also be taken into account; using a heavy grinder for prolonged periods can be exhausting. Additionally, choosing a grinder with an anti-vibration handle or a built-in dampening system can reduce the amount of vibration, easing strain on your hands.
Selecting the Right Grinder Size
The appropriate grinder size is largely dependent on the task at hand, frequency of use, and whether its purpose is for occasional, regular, small-scale, or professional use. For precision work, finishing tasks, or occasional household use, a 115mm angle grinder is typically sufficient. Regular small-scale tasks may require a slightly larger 125mm angle grinder, while a 230mm angle grinder is better suited for substantial, regular work or professional use.
Understanding Power Source and Wattage Requirements
The power source and amp or wattage of the angle grinder should align with the tasks at hand, usage frequency, and the scale of intended use. If portability is a significant factor, consider a battery-powered angle grinder, whereas prolonged usage might necessitate a corded model. Angle grinders with a power rating between 500-900W are generally sufficient for occasional household tasks. For regular small-scale tasks, a 700-1200W model may be more appropriate. Meanwhile, large-scale regular jobs and professional use may require a higher power rating of 2000W and 2500W respectively.
Evaluating Speed Settings
Angle grinders are available with either a single-speed setting or a variable speed setting. While single-speed angle grinders are more straightforward to operate, their scope of use is limited compared to variable-speed models, as different speeds cater to different tasks and materials. A variable-speed angle grinder allows for a wider array of applications, offering a more versatile tool for various jobs.
A Safety First Approach with Angle Grinders
Due to their power and high operational speeds of up to 8,000 RPM, angle grinders necessitate stringent safety measures. Whenever you’re operating one, eye protection is essential as the fast rotation of the disc can send debris, sparks, and fragments flying at high speed.
The guards provided with angle grinders are not optional extras, but vital safety components. It’s generally discouraged to operate these power tools without their guards in place. Remember, safety is paramount when using an angle grinder, and investing in adequate hearing and eye protection is non-negotiable.
Understanding the Versatile Applications of Angle Grinders
Originating as devices designed for abrasive discs, angle grinders have evolved into multi-purpose tools, thanks to their popularity and versatility. Manufacturers have expanded their uses well beyond their initial purpose.
Unsurprisingly, grinding remains the primary function of an angle grinder. Equipped with the right grinding wheel, an angle grinder can effectively smooth down metal weld lumps, sharp corners, and similar rough spots into a smooth and safe-to-handle finish.
Beyond grinding, angle grinders are frequently employed for sanding and surface preparation. Fitted with a suitable sanding pad, they are adept at stripping old paint and addressing rough spots and defects. Replacing worn sanding pads is cost-effective, making it common to use an angle grinder to refurbish old lumber before thickness planing.
With the appropriate cutting disc in place, an angle grinder excels in cutting various materials. These include hard substances such as masonry, tile, concrete, and metal, as well as softer materials like plastic, wood, and PVC.
Angle grinders can also be transformed into efficient finishing tools with the help of polishing discs and a bit of polishing compound. Further, they are suitable for use with wire brushes to remove rust or add a matte finish to a shiny surface. Moreover, the right sharpening disc allows an angle grinder to quickly sharpen a blade.
Conclusion
In conclusion, the versatility and power of angle grinders make them an essential tool in various industries and crafts. However, despite their widespread applications, the importance of safety precautions when using these power tools cannot be overstated. Proper protective gear, including eye and hearing protection, is crucial, as is the correct usage of grinder guards. In essence, an angle grinder’s utility is maximized when safety protocols are diligently adhered to.