In this article, we’ll teach you about six kinds of grinders and six kinds of sanders. After reviewing the similarities, differences, and major distinguishing factor between these two power tools, we’ll advise you when to use each one. Finally, learn our thoughts about which tool is better overall.
What Is a Grinder?
There are six tools that fall under the category of ‘grinder’. They all use abrasion and friction to remove material. Grinders are primarily used to machine metal, although there are wood, concrete, plastic, and tile applications for grinders as well.
The six tools in this category are:
Angle grinders are handheld power tools that can be used with a wide variety of attachments. The best angle grinders can cut metals, rebar and tile, grinding concrete, sharpening tools, and removing mortar.
A bench grinder is a heavy stationary machine that must be attached to a floor or table. Two abrasive wheels spin at high speeds. Tools and materials are introduced to the wheels to grind away unwanted material.
Belt grinders stretch an abrasive strip of material between two spinning wheels. They are usually mounted to a bench. Belt grinders are primarily used for precise sharpening of knives.
Polishing, grinding, and cutting tiles are tasks best done with a wet grinder. These handheld tools release a stream of water over the cutting or grinding surface to keep it cool while friction and abrasion are applied.
Detailed etching, engraving, polishing and honing can be done with these handheld, high-speed rotary tools. Die grinders are also sometimes called ‘dremels’.
High quality dremels can actually can a variety of material in their own right, provided you have the right attachments.
Horizontally rotating abrasive discs spin at high-speeds on the bottom of a floor grinder, which is pushed from behind like a lawnmower. Floor grinders are used to scour tile and grout and to grind down wood and concrete floors.
What Is a Sander?
Sanders are a category of power tools that are primarily used to shape, smooth, and finish wood. This category includes both stationary and handheld tools.
The six tools in this category are:
Rather than sheets of sandpaper, this handheld machine uses continuous loops of sanding paper to aggressively remove material from wood. The belt sander’s motor feeds the sanding belt across the sanding pad and back through the machine, effectively scraping away any material it comes into contact with. Belt sanders are best for quickly removing a lot of material and blasting away exterior finishes.
Random Orbital Sander
This common handheld tool is used for fine finishes on furniture, trim, and baseboards to achieve a super-smooth surface condition. The head of the sander moves in eccentric motions, while the attached sanding pad moves in circles. This prevents scarring and scuffing of wood should you accidentally sand against the grain.
Random orbital sanders are fairly gentle, as their removal action comes primarily from vibration.
Rotary sanders can be handheld or floor mounted. They feature a sanding head that turns in a circle. They can be used on nearly any material. The most frequent use for handheld rotary sanders is sanding floorboards near where they meet the wall.
This specialty tool is used by flooring professionals to remove material or debris from solid wood floors. Custom sanding belts fit around the drum, which is powered by a strong motor. Drum and motor sit in a frame that is used to push the sander over the floor while the operator walks behind.
They are used to level out major imperfections.
A disk sander features a table to hold the workpiece and a large wheel, usually steel. Sandpaper discs are attached to the spinning wheel. The angle of the table that supports the workpiece can usually be tilted, to change how the wood is introduced to the sander.
These stationary tools require skill to use effectively. By tipping and tilting the wood and moderating the amount of pressure applied, the operator can exercise greater control over the rate of material removal.
This small stationary sander features a rotating cylinder covered in abrasive material. The tubes of sanding paper used to cover the rotating cylinder are called sanding sleeves. Spindle sanders often have the option to swap in larger or smaller cylinders.
Some larger models may even have the option to be converted into belt sanders. Most spindle sanders have a dust port for vacuum collection of sawdust.
Oscillating spindle sanders not only turn, they also move the spindle up and down. Like a disc sander, the material is presented to the sanding paper, rather than the other way around. Spindle sanders are used for sanding curves.
Grinder vs Sander
Now that you understand the basics of grinders and sanders, let’s compare and contrast these two power tools.
Grinders and sanders have several important similarities. They both achieve the same purpose using the same method. Specialized tools are available in both categories.
Grinders and sanders both share a similar purpose — to remove unwanted material.
Both grinders and sanders remove material through friction and abrasion. Abrasive material is embedded in resin or adhesive attached to metal or paper. The resulting sheets, discs, or blades are attached to the sander or grinder, and the abrasive action is provided by a motor.
Grinder and sander are general terms used to refer to a broad category of machine. Within each of these categories are a variety of specialized tools, each with its own strengths and weaknesses.
While several surface similarities between grinders and sanders exist, the two categories of tools have deeper differences. Grinders are more versatile than sanders, but not as safe. They are designed to be used on different kinds of material.
Angle grinders and die grinders are particularly versatile tools. Different discs, burrs, blades, and other attachments can be used to customize the purpose of these machines.
Angle grinders are commonly used to cut wood, brick, and metal. You can use an angle grinder for cutting pavers, grinding concrete, and even to sand wood (although a sander would be the preferred tool).
Sanders can only be used to sand. Grinders in general are more versatile than sanders, as they can be used with many different types of material.
Grinders are primarily made to be used with hard materials such as metal, concrete, and tile. Sanders are geared towards softer materials such as wood. While sanders use flexible sanding paper, sanding belts, or sanding sleeves, grinders use rigid discs or blades.
Both sanders and grinders operate at high-speeds. Getting hair, jewelry, or clothes caught in the mechanisms can cause injury. However, grinders are generally more powerful than sanders, and their abrasion is much more aggressive.
Some grinders, such as angle grinders and die grinders, can be used to cut through metal. This makes grinders more dangerous than sanders, overall.
Major Distinguishing Factor
The major distinguishing factor between grinders and sanders is how powerful each tool is. Grinders are a heavy-duty, high-powered tool that aggressively removes material such as metal, mortar, and concrete. Sanders are lighter-duty, lower-powered tools that remove material only from wood.
When to Use a Grinder
Use a Grinder for Heavy Duty Material Removal and when Metal is Involved
Belt grinders are commonly used to sharpen knives.
Angle grinders can be used to remove rust, sharpen tools, or even grind hardened concrete off your shovel. With tuckpointing wheels, they can remove mortar from between bricks.
Angle grinders and die grinders with cut-off wheels attached can be used to slice through a wide variety of materials including rebar, cast iron, stainless steel, aluminum, tile, and concrete.
Die grinders are the tool of choice when detailed work is involved. From honing the inside of molds to etching and engraving all kinds of metal, the die grinder is one of the most flexible machining tools available.
Walk-behind floor grinders and wet grinders are the two types of tools in this category that are not used primarily for metal applications. Choose a floor grinder to smooth concrete and wood flooring, or to remove adhesive from tile. Use a wet grinder to cut tile.
When to Use a Sander
Use a Sander When You are Removing Material from Wood
Belt sanders make quick work of removing film finishes like polyurethane, varnish, or lacquer. They can also be used to remove wood that has been affected by penetrating finishes such as stain. Before tackling your wood floor, practice on scrap wood to avoid gouging.
For fine finishes and smooth surface areas, a random orbital sander is best.
To deal with heavily damaged or unlevel solid wood flooring, a drum sander might be the only option. These heavy tools can easily gouge your wooden flooring, so we recommend leaving drum sanders to the professionals. It is possible to rent one for the weekend.
Disk sanders are used for smoothing end grain. They can also be adjusted to smooth straight cuts or mitre cuts.
A spindle sander can be used to remove sanding grooves on the edge of a board, or to sand concave surfaces created by a band saw. They can achieve smooth, fine finishes on chair legs, banisters, and other small woodworking items.
The one sander that you might use on metal is a rotary sander. With the right kind of sanding paper, they can be used to remove rust and paint from metal, polishing the surface to a high shine.
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Which is Better, a Grinder or a Sander?
A grinder is better when you need to cut, grind, polish, or sharpen metal.
A sander is better when you need to remove material from wood.