A die grinder is a handheld power tool that can be used for grinding, honing, sanding, machining and polishing material such as metal, plastic and wood. These tools are typically pneumatically driven.
Before CNC became widely used, die grinders were greatly relied upon for contouring. Today, CNC handles most of the contouring for the interior surfaces of die and mold.
However, die grinders are still being used for hundreds of applications. These machines are often utilized for cylinder head porting, engraving, and general shaping of a part.
Methods of Cutting Action for Die Grinder
The cutting action may be performed in various ways, such as:
- Machining with a small drill bit, burr or endmill
- Sanding using coated abrasive
- Grinding with bonded mounted stones, grinding points, or abrasive stones
- Honing using mounted points that are fine-grit
- Buffing or polishing with cloth or fiber drums
- Lapping with a mounted lap and lapping compound
Methods of Holding the Cutter
The collet often holds the cutter, which is a suitable means of chucking it in and gives it the concentricity necessary for high-RPM use.
It enables quick cutter changes as well. There are other quick-change chucking systems utilized in some applications, similar to the chucking types often found on pistol-grip drills.
Abrasives are formed for different purposes. Abrasives are often commercially available as dressed stones that are rectangular in shape. Abrasives both natural and synthetic come in many shapes, and may be classified as bonded or coated abrasives.
1. Bonded Abrasives
A bonded abrasive is made up of an abrasive material within a matrix. This matrix (which may be made with either glass, rubber or clay) is known as a binder.
The mixture of abrasive and binder is typically shaped into sticks, blocks or wheels. Aluminum oxide is the most popular abrasive but there are also other common options like silicon carbide, garnet and tungsten carbide.
Artificial sharpening stones readily available as a two sided block of bonded abrasive, each side varying in grit grade as the other. Bonded abrasives should be dressed and trued after usage.
For those who are not familiar with the term, dressing denotes cleaning the waste material from the surface to reveal fresh grit.
Dressing may necessitate that you place the abrasive under running water and brushed using a specialized brush or it may be ground against another abrasive, in order to dress a grinding wheel.
Truing, on the other hand, is the process of restoring the abrasive to its original shape (surface). Stones and wheels tend to wear unevenly, so the surface is no longer nor in the same diameter throughout. Without truing, it leads to uneven abrasion.
Also Read: Things you need to know about stone grinding
2. Coated Abrasives
This type of abrasive is made up of an abrasive fixed to paper, cloth, resin, rubber or any backing material that is flexible. Sandpaper is a widely used coated abrasive.
The minerals used in coated abrasives are often the same as the ones in bonded abrasives. A bonding agent is placed to the backing to give it a flat surface so grit is adhered.
You can shape coated abrasives for use in orbital sanders, as well as for wrapping around hand pads, or closed loops which can be used in belt grinders, and so on. Diamond tools however are usually abrasive in nature.
Safety When Using a Die Grinder
The one thing that every operator from any part of the globe agrees on is the use of safety glasses to protect the eyes when using a die grinder. But of course, various locations also have their own personal protection guidelines when operating this machine.
These include: Having eye and face protection, such as a face shield, which refers to a polycarbonate window, that hang from a headband to cover one’s face when using the die grinder.
Use eye protectors in clear versions with various levels of shading.Use hearing protection, like headphones and ear plugs. Remember that die grinders can be very noisy and using it for hours on end can significantly impact your hearing over time.Have sufficient skin protection.
This means you’ll need work gloves and even fire-retardant clothing in some cases because operating the grinder can cause sparks which may be a fire hazard.
Have sufficient protection against the respiratory and alimentary tracts. Such protective gear include a paper mask or even in some cases, a respirator especially if the operator has breathing issues.
Also Read: Safety rules for die grinding
Do Die Grinders Have Safety Features?
The short and simple answer is YES. They are equipped with features that significantly enhance safety of the user and reduces risks of accidents. But of course, they’re never foolproof. In any case, here are some of its safety features:
Majority of pneumatic die grinders have a spring-loaded “kickstand” mechanism for the throttle. And this is located between the grinder’s body and the throttle lever.
This feature keeps the throttle from opening unless it is intentionally done by the operator. It also prevents accidental activation.
This kickstand mechanism is similar in principle to a gun’s safety catch. Die grinders that have electric motors also have safety features unique to them. These features include grounded cases as well as double insulation.
The grounded cases are connected to a grounding conductor. Some tools have both while others have one or the other.
A die grinder is without a doubt a very versatile handheld tool that can work with metal, plastic or wood. It works by rotating at speeds measured in RPM. Some of the best die grinders can reach as much as 30,000 RPM so it will be able to work on any material without a problem at all.
The key to getting the most out of this tool is to be familiar with its operation and to be aware of the best applications and material to use for your project. It’s also just as important to be aware of all the safety guidelines when using this equipment.