There are many types of power tools that help us perform a large number of specific tasks. Whether we are amateurs, independent professionals or operators in large industries, we will always find ourselves with the need to carry out some cutting, grinding or polishing operation. This will require versatile tools and one of them, practical, portable and relatively inexpensive, is the angle grinder.
On the market today there are hundreds of different makes and models of angle grinders. It is natural that our search is directed towards a good quality tool at the best possible price. However, before making a decision, we must make sure that the chosen grinder suits our needs. The way, the environment and the reason why we use it play a fundamental role in choosing the best grinder for us.
Some time ago we provided a short guide to guide the reader in choosing the right angle grinder. Also, since it is an effective tool, but dangerous if precautions are not taken during its handling, we detail a series of tips for the safe use of grinders.
Now, depending on the intended use and the new technologies that manufacturers are adopting to offer increasingly powerful and durable grinders, we are going to expand the spectrum of factors that must be taken into account to effect the right choice of our angle grinder.
In principle, it should be clarified that there are three main categories of grinders that hobbyists or professionals can choose from. Therefore, the first step to purchase is to determine which category suits us.
Corded grinders
This is the most powerful of the three categories and also the most popular. Most users have electrical outlets in their work environment, so a corded grinder is the best option in that case, since being more powerful it can be used for long periods without the risk of running out of batteries.
What to look for in a corded grinder
one. Electrical requirements: These are the most important factors when choosing the tool. Voltage, wattage, and amperage vary widely between grinders. We can choose between 110 and 230 volts AC, a power range of 500 to 2500 watts and an amperage between 4 and 15 amps. If we are looking for a DIY grinder, surely a low-end will be enough. On the contrary, at a professional or industrial level, grinders with higher amperage, at least 7 amperes, are suitable. A lower power would present great difficulty in the most demanding tasks.
two. Speed: Sufficient speed is required for cutting work. So let’s look for a grinder that can supply at least 10,000 rpm.
3. Size: The size of a grinder is determined by the diameter of the abrasive disc and not by the overall length of the machine. Larger grinders use large wheels, making them ideal for heavy duty jobs. That is why if we are professionals or work in the industry, a large grinder will undoubtedly be the one, because they are fast in the most demanding tasks. Instead, hobbyists consider small grinders to be ideal because the smaller blade allows for greater precision on small jobs.
Four. Durability: When we invest in a power tool, we want it to last a long time. Attentive to this, recognized brands offer products with a good guarantee that give us confidence to use the product to its maximum capacity.
Cordless grinders
If we want a little more versatility in a grinder, a cordless model can be our tool that, although it is not as powerful as corded grinders, it has the advantage that the energy is provided by batteries. This allows us to work anywhere, regardless of whether there are electrical outlets or not, or in large spaces (eg gardens, grounds or parks) where the cord may not reach the electrical outlet. In addition, this technology has evolved a lot and there are already brands that offer a single battery for all tools, in that case, a significant economy is generated for the user.
What to look for in a cordless grinder
one. Weight: The main reason we chose a cordless grinder is probably because we want a more versatile and portable tool. If we acquire a heavy grinder we will not be meeting the objective. Therefore, let’s choose a model whose weight does not exceed 4 kg.
two. Power source: lithium ion technology is the latest and best for batteries. It is recommended to select a grinder powered by 18 volt Li-Ion batteries. Below we will detail another important characteristic to take into account when it comes to batteries.
3. Speed: As with corded grinders, speed plays an essential role in the efficiency of a grinder. Let’s decide on a model capable of supplying 10,000 rpm.
Four. Additional functions: Different brands have different characteristics. Let’s compare the features and choose the model that has the most preferred features.
5. Warranty: Never buy a power tool without warranty!
Pneumatic grinders
These tools are powered by compressed air and can be very powerful. Any user who has an air compressor in his workshop and who uses a wide variety of pneumatic tools will find this type of grinder very appealing.
What to look for in a pneumatic grinder
one. This is a category that has hundreds of different shapes and sizes. When we have determined what type of pneumatic grinder we want, let’s select one that is ergonomically designed and lightweight. This will reduce fatigue when working for long periods.
two. Let’s choose a well-known and reliable brand. In this way we will know what quality we can expect from the tool and that the company will offer good support in the event of any inconvenience.
Important technology considerations
If our intention to use the grinder goes beyond occasional tasks, it will be convenient to pay attention to these two characteristics presented by the most professional models and, therefore, higher cost, but which amply guarantee us the investment for the benefits offered and the results obtained.
Shielded windings
During operation, all power tools often inadvertently carry dust-containing particles such as silica, metal shavings, cast iron chips, or small pieces of grinding wheels that enter the motor with the cooling air. To avoid mechanical problems resulting from this behavior, some manufacturers employ measures to protect armature windings and field coils in their tools, especially angle grinders, which can generate large amounts of dust.
This protection of the windings is called armor and grinders that have this feature are known as armored grinders. Usually the field windings are wrapped with cotton strips and impregnated with synthetic resin. Cage-type covers are used in the armature windings, which in turn are impregnated with synthetic resin. This creates an effective shield especially suitable for angle grinders.
Shielded grinders are expensive, but the lifespan of their motors is up to five times that of unshielded motors, which justifies the expense if we work in the professional or industrial environment.
Einhell brand grinders were disassembled in which it is possible to observe the shield, DP (dust proof):
An improved turbine is observed. Incorporation of tissue in the armature, which displaces dust fragments and allows it to contain more protective resin. Comprehensive bearing protection.
Epoxy protection is observed in the winding of the fields.
Interchangeable multifunction batteries
Some manufacturers are already equipping their cordless tools with novel microprocessor-controlled parallel battery management systems. In this video we can see an example of this new technology.
These systems, which provide a pack of two 18 V batteries each (36 V in total) with their corresponding charger, offer many advantages that we can summarize in the following list:
- Modern microprocessor-based technology, providing effective battery protection against overcharging and overheating.
- Smart charging that offers maximum durability by allowing the charging process to start regardless of the battery charge level.
- Individual control that guarantees full power, where an intelligent control system individually controls each battery ensuring its full charge.
- 3-step indicator that provides permanent visualization, not only of the battery charge, but also of extreme temperature conditions.
- Lithium-ion technology against self-discharge.
- Highest quality for the most demanding requirements, because only the best quality batteries are used.
- Protection of the battery against impacts, through a triple rubber shell design to ensure optimal protection against damage.
To understand why these systems are so useful, let’s examine their capabilities:
- Multifunctionality: A single battery pack is suitable for many applications, since it can be used in different tools from the same manufacturer, regardless of the energy they consume.
- Combination capacity: only the power that is needed is used. The battery pack is double, but a single battery can be used if the tool is small and has low energy demand (for example, grinders or drills) or both batteries can be used in parallel in the case of larger tools and high consumption (for example For example, garden tools such as edgers, chainsaws, and lawn mowers).
- Economy and environmental protection: the battery pack is adaptable to all cordless tools from the same manufacturer; This eliminates the need for so many different chargers, saving money, storage space and contributing to a healthier environment.
All these functions can be seen in the following video.
