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Bench Grinders: The Info You Need To Know

Bench Grinders: The Info You Need To Know

Bench grinders are amazing pieces of equipment. They are some of the least recognizable to the casual tool user. Bench grinders are what keeps tools as useful for as long as they are. The full range of what they are used for is dependent on the type of work required.

The more tools you can use, the handier you will be. Bench grinders are one of the most valuable instruments to learn to use. It saves time and money on replacing easily repairable or sharpenable tools. They are cost efficient, usually costing a fraction of tool sets that would need to be replaced.

Workshop with a Bench Grinder

This guide will walk you through the must know information on what a bench grinder is and its uses. It will give you a solid foundation for what a bench grinder can do and how to safely use one.

What Is A Bench Grinder?

Bench grinders are part of the arsenal of tools used in workshops and metal shops. It can be utilized for a broad range of functions. The most important thing to consider is how it is setup in most workshops. Bench grinders are work bench tools. This means that they are made to be used for both long and short projects.

Bench grinders are a two wheel system that can:

  • Sharpen tools that have become dull.
  • Fix broken blades for steel fans to riding lawn equipment
  • Polish and fix up small pieces of steel.

Bench grinders while effective are delicate pieces of equipment. On two ends of the main body are two wheels. These wheels are carefully made pieces of stone that have grit levels. These porous pieces of stone act like mini blades for “chipping” at metal.

Sharpening Knifes one of the many uses of a Bench Grinder

The reason they are so effective is due to how they rotate. Each wheel has a factory issued rotating speed. When used in conjunction with the proper wheel grit, bench grinders can quickly sharpen/repair tools. Each wheel is fragile and moves at high speeds. This means the danger of fracturing or shattering is great.

Every part of the bench grinder is made to completely control the speed and power of the grinding wheels safely. While the main sections are relatively straight forward, attention to each ensures safe usage without accidents.

The Important Parts

Each piece needs to be thoroughly checked before and after each usage. To put it simply, bench grinders are as dangerous as they are useful. Like most tools in metalworking shops, the grinders can cause bodily injury many ways if misused.

The Spark Deflector

The spark deflector is a small piece that guards the upper and lower parts of the wheel while it rotates. Its name is straightforward. It prevents sparks from flying as the wheel rotates during use. It is not easily cracked or damaged unless the overall machine is grossly misused. Without it, sparks would be flying in all directions.


The eyeshield is one of many pieces that prevents against wheel fragmentation. It is on the upper part of the bench grinder. It's a first mark safety measure for motor control.

Eye shield to protect form harmful sparks

The Coarse Wheel

The round stone that rotates and grinds against the materials. It’s categorized based on the materials that are being shaped, cut, or altered. The coarse wheel is what does the heavy lifting. It continuously and gradually forms the materials it is being used.

Wheel Guard

The wheel guard holds the wheel in place. When improperly mounted, it can prevent the wheel from splintering or cracking. One of the most common reasons for rotating wheels being split is due to improper mounting. The wheel guard saves potential costs for damages.

Fine Wheel

The fine wheel is the side of the grinder typically used for shining or polishing pieces of steel or other parts. When replaced with a polishing brush it quickly gets a better shine out of materials when used for finishing. This can save time and money on handheld sanders but requires more care.

Fine Wheele on a Bench Grinder

Tool Rest

The tool rest is a hard surface just outside of the rotation area. It provides a smooth, consistent surface for placing materials to be adjusted. Without it, cuts and shapes would be uneven or inconsistent. This could lead to wheel fragments or worse.

The entire point of using a bench grinder is the controllability and consistency. Changes in consistency or choppiness can be dangerous to the rotation speed. When coupled with the delicacy of the fine and coarse wheels, the tool rest is an essential part.

Why A Bench Grinder Is Important

A good grinder is an essential part of the metalworking process. The process of adjusting varying sized parts needs to be simplified. Bench grinders with various grit stones make it easy to change a lot of similar metal pieces in one set. They can repair several tools without needing to replace the grinding stone.

Tool Repair with a Bench Grinder

Bench grinders are better to use than other grinders for a few specific reasons:

  • Bench grinders offer more control on a more minute level.
  • Bench grinders can do more than just grind or polish.
  • They are cheap compared to other industry grade tools.
  • They are easy to use and maintain.
  • They don’t cost much to repair or replace.

Bench grinders come in a few sizes. Each can be used for somewhat similar products and metals until the price range reaches past a few hundred dollars. The difference lies in the speed at which they rotate and how quickly they can be adjusted. Bench grinders don’t need to be used for every tool repair, but they can be. They are functional beyond just cosmetic repairs.

When used in conjunction with other sharpening or graining tools, its long-term use is extended. The more they are used in the proper way (the stone’s track), the less chance of quick stone replacement. Which means when compared to typical gradual sanding products, they can be more cost efficient.

Regular sanding tools cost a lot to maintain. They grind and polish more slowly which can prevent mistakes, but rack up project time costs. The difference in time saved alone makes bench grinders far superior due to the speed and flexibility.

Bench grinders are also not very expensive. For most small projects and home based, the max spent would be a couple of hundred dollars. Compared to the assortment of equipment if assembled individually, it’s a steal.

Small Bench Grinder in a Workshop

Bench grinders are also far safer than comparable equipment for polishing, buffing, and shaping metal. While it has one of the most fragile grinders, it’s still far safer due to the number of safeguards included. It also only takes a few hours to get familiar with how they work.

Who Needs/Uses A Bench Grinder?

Anyone that needs a bench polisher, a metal shaper or grinder could use a bench grinder. It consolidates the best of multiple tools. Who uses or needs a bench grinder?

Woodworkers that want a simple tool for keeping their other ones sharp. Woodworking kits range from tools that need precision. The easiest way to keep entire kits sharp is with a bench grinder.

The same applies for a range of skilled tool based work. Construction specialists need a bench grinder for polishing or shaping roof pieces, metal piping sections and more.

Homeowner with a Bench Grinder

While some homeowners don’t decide to buy a bench grinder, they should. The cost of making simple metal adjustments for repairing plumbing or home tools when they break is minimal. It can save homeowners not only hundreds but thousands of dollars in repairs that could be done themselves.

It’s up to how handy you are or are willing to be. For those that don’t like a challenge, a bench grinder can be a bit tedious. To get the most out of a grinder requires careful attention to detail.

How Do You Use A Bench Grinder?

Using a bench grinder is easy. The questions to ask when setting up are as follows:

  • What is your primary intention?
  • Are you using it to buff, polish, sharpen, or grind away at a piece of metal?
  • What kind of metal are you going to be working?
  • What is the purpose of this piece of metal? Is it a part of a project or is it a tool?
  • What grit are you using?
  • How long do you anticipate it will take?

These initial questions will give you an idea of what you need to have in place. The variations in grit are basically how finely the stone will connect with your piece of metal. When using a bench grinder, avoid using one stone for different types of pieces of metal. Using the same stone for various types of metal can lead to the stone becoming damaged.

The stone grit needs to match the speed of the grinder rotation. If it's too slow, it may result in the metal or the stone itself fragmenting. This means that it could lead to pieces spreading apart or falling. At an advanced stage, it can cause explosions, the destruction of the bench grinder or harm to the user.

Taking into account how long your activity will take is important. The point of a work bench is to be able to be used when sitting or standing . If you will be standing or sitting for extended periods of time, it needs to be set up in a way that is fluid for your posture. Sudden movements of the metal or pieces due to fatigue or jitteriness can also damage the stone or piece of metal.

When compared to a power grinder, its control on polishing or buffing is better. Power grinders require constant force or weight applied to the intended surface. Power grinders can slide pretty and become dislodged if not careful. It’s harder to lose control of a bench grinder because of its sedentary setup.

Keeping The Balance

The only dislodging danger that a bench grinder offers is in the wheel setup. When not mounted, coarse wheels can become dislodged. This can lead to the rotator underneath being destroyed if not paid attention to. Checking the washers when the wheel is being set up can prevent dislodging.

The balance of a grinder wheel is similar to that of a car tire. If the tire isn’t rotated and balanced, it can fall off or cause internal damage to the rotating mechanism. Grinder wheels work off that simple principle. The other way that the balance can be disturbed is if the grinder wheel is broken or fractured.

Keeping the grinding wheele in balance

It’s important to check the quality of your grinding wheels before and after each use. This is done by making sure they are both on track. After making sure proper spacing, tapping the wheel itself can provide the sound that lets you know the status.

If you hear an audible ringing sound similar to that of a hotel bell, it means that it is in good shape. If you don’t hear anything, it means that the wheel is damaged or cracked and is not safe or advisable to use.

RPM & Maximum Usage Speed

The speed at which the wheel rotates dictates both the time, it takes to sharpen or buff a tool. It can also dictate how fast the device will heat up when it direct contact with metal. 3500 RPMs are usually the standard for a grinder that is professional grade.

The speed at which the wheel rotates is dictated by safety and size. Bigger wheels don’t spin as fast because they are more dangerous at higher speeds and have a greater chance of shattering. While the dangers using a power grinder are less, it’s slower.

It’s important to keep the grinder wheels as fresh as possible. As the pores that are used to make the wheels do their job become clogged, they become ineffective. Some users try to compensate by pressing harder on the wheel. This is not only dangerous, but it is also pointless.

The harder you press non-porous materials together, the more heat is generated. That is all that is generated, not an improvement. This leads to the grinder eventually overheating or the tool melting or being destroyed. That’s without including the possibility of the user becoming substantially injured.

Matching the wheel speed to the material is the only way to assure the grinder will work suitably and safely. The maximum wheel rotation speed is factory mandated for a reason.

Using It At Angles

While angles are important for maintaining an edge, some users try to use the side of the wheel. Whether it’s to get a bit of extra usage out of the wheel or just because they don’t know, this rule applies: don’t do it. The reason is when the rotating wheel is used on the wrong side it can lead to overheating.

It can also lead to the wheel fracturing due to the pressure on the rotator. The wheel is designed for forwarding pressure to be placed on it. Essentially it’s the difference between cutting a tree with the blade of a sword versus slapping it against a rock sideways.

Using an angel  to shapren a chizel

What do you think would happen? It would shatter into pieces. That same principle happens with grinding wheels. The tool guard’s essential function beyond providing a good surface is to prevent explosions.

Rolling Pan Vs. Dip Pan

Depending on the type of 8 inch bench grinder or 6-inch bench grinder you decide to invest in, cooling is a factor. The way you choose to deal with your metal heating up is dependent on the size of the tool and type of bench grinder.

Some have rolling pans that as they sharpen help to cool the metal to prevent overheating. Others have dipping pans that are within arms reach that they dip metal in to prevent excess temperature changes. As metals quickly heat up and decrease in heat, it can warp the composition of the metal.

Having a dipping tray makes the entire process of sharpening or molding metals less time-consuming. The alternative is to wait for the metals to cool down or risk overheating the metals. If the metals heat up too much, they can be weaker or fall apart easier.

A Few Types Of Bench Grinders

Not all bench grinders are created equal. The differences come down to more than just variations in size. Each serves a unique function yet with an interchangeable way of getting the job done.

  • Variable Speed Bench Grinder: A variable speed bench grinder is not exactly as it sounds. The main function is to offer speed variations to increase control and flexibility. The reason its important is that most speed benches don’t give control over the speed and require your touch to compensate. With multiple settings, variable speed grinders help compensate for touch problems.
  • Electric Grinders: There are portable electronic grinders that function as mini bench grinders. They are more easily transportable and used during great tool usage projects. It’s for the possibility of needing tools repairs as well as metal adjustments on the fly while at a project site.
  • Woodworking Bench Grinders: Woodworking is a precision based skillset. The tools need to be capable of cutting within a half centimeter of accuracy. For woodworking, slow speed grinder sharpening makes it easier to keep tools perfect.
  • Automotive Grinders: Metal bench grinders opposed to wood workbench grinders which mean their stability is more important. The focus on being reusable for extended periods without stone adjustments is important due to the volume of metal work that goes through a machine shop. The types of modifications done can include door handles, engine parts, body pieces and more.

How To Mount A Bench Grinder

The most important thing to consider when using a bench grinder is how it is mounted. The proper process for mounting isn’t complicated. It’s as simple as:

  • Taking the measurements for the distance between bolts and the table.
  • Drilling holes large enough in the base of a piece of wood that would slide over the workbenches available holes.
  • Ensuring your measurements are correct.
  • Putting the holes on the base of your grinder flush with the drilled holes.
  • Sliding washers through on one side and then the bolts.
  • Tightening them for security, but not tight enough to crack or damage the board.

Tips To Keep In Mind

When using a bench grinder, there are a few safety tips to remember:

Take care when grinding
  • Be aware of the heat of your metal. If you don’t pay attention, it can overheat and destroy the grinder or the person using it.
  • Check your grinding wheel and brushes. They can fall apart faster than you would imagine. The amount of time they last vary from brand to brand from days to months. It’s dependent on the amount of usage and intensity.
  • Pay attention to how your bench grinder is mounted; any mistakes can lead to a lot of damage.
  • Don’t spend skimp on your first grinder. If the project is important, it’s worth getting the tool that gives you most control.

In Review

The grinder ratings you can find give little sign to how well they suit your needs. Bench electric grinders can do a lot more than grind.

Spending the money means looking at the tool as a way to get more use out of both new and used tools alike. The amount of money you will save goes beyond tool and time costs.

The biggest thing to keep in mind is safety. It's worth mentioning how any lapse can lead to shards propelling around your workspace. How well you acclimate yourself to the tool can be the difference between a world of success and a massive disappointment.

Like any tool, it isn’t the tool itself that dictates how well it works for you. It comes down to learning how to make the most of it beyond its go to function. Bench grinders are no different.

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