Everything you need to know about grinding woodworking tools on a bench grinder

tool sharpening is a huge subject, some of you have your favorite techniques, be it with stones, diamonds, sandpaper, belts or machines, others seldom sharpen and have no idea how easy and more enjoyable it would be to make if learn how to do it correctly therefore we have created a series of free tutorials for all aspects of the problem below this video. I will link to many of those resources. I hope you take advantage of them. You will learn a lot today. the topic talking about

grinding

straight edged

tools

such as chisels and smooth irons on a

bench

grinder

, this is a process that is only done occasionally, usually you have to repair a damaged tool or reshape a bevel that has been altered afterwards of many hours of sharpening his stones. of course you can use a coarse diamond or water stone to re-grind a bevel by hand but it would be a slow and tedious process that's what

bench

grinder

s are for but with speed comes danger a bench grinder it can be an aggressive machine. easily overheat your steel or remove too much and end up with a crooked edge.

There is a lot to learn about bench grinder equipment and techniques, so this is going to be a pretty comprehensive tutorial. the topic I guarantee you'll get some useful tips that you may have never considered before. Divide this topic into several parts, starting with the grinders and accessories themselves, then moving on to the fundamentals of bevel and

grinding

techniques, including edge blunting and facet control. This is going to be a pretty thorough walkthrough that's free to you because Woodturners Wonders has footed the bill, so let's give them their 15 seconds before we get started. Some people are a joy to work with, like Ken Rizzo at Wood Turner's Wonders, chill that's where I get my turning stuff like sanding supplies and cbn wheels for my grinder seriously if you haven't seen what cbn wheels can do Do it for you, you are missing it.

I'll put a link under this video, use it and tell Ken I sent you my first bench grinder, a high speed 6 inch model with a horrible tool rest and terrible wheels like this one. We'll talk about wheels and rest shortly. Let's focus on the grinders themselves for a minute. You can buy one of these small grinders as long as you understand the limitations and come and be safe for them. be careful not to overheat your tool which means submerging it in water every few seconds don't neglect this because you can bluish and ruin an edge before you

know

it later in this video we'll discuss some other techniques that will help you with the slow speed grinder will make this much easier.

These run at about 1,750 rpm, about half the speed of a regular grinder. You can still overheat a tool at 1750 rpm if you use regular wheels instead of the CBN wheels I use. on mine so keep your water handy but with a slow speed grinder you will be submerged in water much less and heat is much less likely to escape from you and ruin your bezel before you

know

it, these grinders are also larger With eight-inch wheels, we'll talk about hollow grinds later, but the size of the wheel affects the angle of its bevel. A six-inch wheel produces a more concave shape with a thinner cutting edge than an eight-inch wheel. a small grinder but bigger is better the power is nice too but i think its a lesser factor than a lot of people think this grinder makes maybe a quarter horsepower but i never felt it lacked power when i was grinding

tools

because i am rarely removing a large amount of steel at once Aggressive grinding is a good way to overheat a tool as you will soon learn that light passes are the way to go so not much is really necessary power for this type of job where i notice the difference in power is so the time it takes is for larger grinders with heavier wheels to get up to speed this one horsepower grinder hits speed much faster than the half horsepower grinder, you may not care about that, but if you're into wood turning and begin to frequently touch up your tools on a grind Adora, those extra few seconds can become an irritation, so while any grinder will work for sharpening

woodworking

tools like chisels and smooth irons, I prefer a slower speed, larger wheel, and at least a half horsepower motor. strength if you think you could do it now or even later. getting into wood turning or cbn wheels go full power now to make it future proof one final note my 8 inch grinders don't have wheel covers because cbn wheels won't blow up and kill me but my grinder more small with traditional wheels has covers installed and sworn by Scioscia, these plastic guards are also good, especially if your grinder does not have spark deflectors on top of the wheel covers, but they are not a substitute f or safety glasses, Trust me, you don't want a piece of steel pulled out of your eye, and while we're on the subject of safety, wear hearing protection when using your grinder and a dust mask, especially if you're coating the wheels.

Grinder wheels can affect the speed and quality of the grind as well as the heat generated so don't just pick the cheapest one and think it will be as good as any you get what you pay for it is usually They are divided into four categories, Silicon Carbide, Aluminum Oxide, Ceramic and Silicon Carbide CBN is the least expensive. They are the gray wheels that come on many bench grinders. They work well for everyday grinding, but they generate heat quickly and are a poor choice for tool steel. Aluminum oxide wheels are sometimes grey, but the higher grade versions are usually white or pink.

These break down better and expose new sharp particles as you work to cut quickly and reduce glazing that can overheat your tool. White wheels are good for most tools. Roses are a bit tougher, so they are useful. or turning tools like gouges that can leave grooves in the edges of your white wheels. Ceramic wheels contain aluminum oxide, plus they are often blue in color and more durable than white or pink wheels while providing fast cutting action, but are expensive for consumable wheels up to half the price of an entry level cbn wheel that will outlast many ceramic wheels cbn wheels are the best for grinding and sharpening tools for a myriad of reasons they last almost forever they don't wear down and get smaller or change shape, they never

need

to be dressed and are much less likely to overheat your tools. why i think they are the best choice if you choose not to use a cbn wheel you will

need

a prep tool because non cbn wheels need regular maintenance as you grind until the surface of the stone is filled with metal particles and glaze over the rate at which this happens depends on the type of wheel you are using, but all non-CBN wheels will need regular maintenance.

This involves pressing the steering tool firmly against the edge of the wheels while the grinder is running. the wheel exposes fresh sharp sand its a messy process and i recommend wearing a dusk mask when you do it because you dont want fine aluminum oxide or silicon carbide dust in your lungs some people like to use the bandage tool for bashing sharp edges outside the wheel as well others prefer to form a slight crown or rounded edge profile believe this helps them reshape crooked bevels because they can use the center of the wheel crown to target specific parts of a wheel's rim tool there are videos online specifically on how to dress up your wheels, some people seem to make an art out of them.

I don't use cvn wheels so I'll refer you to youtube for more on that because a bench grinder can be an aggressive tool. you should avoid very coarse grits you can dull a tool quickly with 60 grit I would not use anything coarser than 80 grit to sharpen a tool and even then I would be careful and use a light touch until I was comfortable as with many things in life there is a Trade-off when it comes to wheeled grits, coarser grits build up heat slower and get the job done faster, but like I said, they can eat into your tool quickly so it takes more skill to do so. a consistent bevel with a coarse grit finer grits are easier to control but run slower and build up heat faster if you are new to using grinding tools you can experiment with three or four different grits somewhere between 80 and 220 for regular wheels until you find what you are comfortable with of course if you plan to invest in CBN wheels for life the cost will discourage too much experimentation in that case if you could only get maybe two wheels I recommend an 80 and 350 grit because those are the most versatile and long run for

woodworking

when you start out use your 350 grit wheel to do all the grinding of your tools as you get more comfortable you can start with the 80 grit wheel for stock removal Heavier Perhaps the most important feature of a grinder that you intend to use for sharpening tools is the tool rest.

Few grinders have stands built in there, even close to adequate. You would really benefit from a large adjustable platform, especially if you are not yet an expert tool sharpener. This not only gives your tool a lot of support. making it much easier to form a consistent bevel, but the large steel surface acts as a heat sink to keep the tool cool. Years ago, I made some wooden tool holders. They're just as convenient or sturdy as aftermarket steel brackets and won't help in cooling, but they're inexpensive, so you can invest your money first in a good grinder or better yet a CBN wheel and then in the tool holder.

I want to upgrade to a good tool rest and when I do I recommend getting one that is part of a larger sharpening system like the Wolverine system or the Kodiak system. I have both. I say this because eventually you will want to use your grinder for lathe tools and it really pays off to have a rest that you can quickly remove and replace with other sharpening accessories and rests on both systems can be moved from wheel to wheel quickly too these rests too They are large, easily adjustable, and sturdy. The Wolverine props are the sturdiest this thing is rock solid but I prefer the Kodiak prop because it's almost solid and equipped with a simple but clever slider system that keeps your tool square to the wheel as you move it from side to side. very handy especially when you're just starting out they even have sliders that hold tools at angles for skew bevels the kodiak holder also pivots in a way that it maintains its distance from the wheel at all angles while other rests require repositioning while adjusting the angle and finally the Kodiak holder includes a set of positive angle stops which are mainly used for turning tools whose angles are measured differently than woodworking tools so stops are not as relevant to blueprints and chisels but you are part of the overall Kodiak system which I think is superior to the Wolverine if you are a wood turner or think you might be in the future before grinding you need to be aware of the differences between primary bevels and micro bevels a grinder is used to form a primary bevel usually at about 25 degrees a micro bevel if you use one it will f Hand shape with water or diamond stones at a steeper angle than a primary bevel perhaps at about 30 degrees the purpose of the microbubbles is to restrict your day-to-day sharpening to that small area along the cutting edge because it is much more sharpening just that part of the bevel rather than the entire bevel, however, over time, that steeper microbevel will become wider as you polish more and more of the primary bevel and the hand honing process will gradually become less efficient until Go back to the grinder and restore your original primary bezel.

The bench grinder is not an all in one tool sharpener it is for periodic resharpening aveer primary bevel so you can sharpen the micro bevel by hand the exception to this of course our turning tools which can be used directly from the grinder, but this is a tutorial for woodworking planers and chisels so we'll stick to those as well because of the speed a grinder provides the concave shape a round grinding wheel creates is called hollow grinding and this is advantageous for woodworkers who sharpen their tools freehand. We will talk about this in our tutorial.of freehand sharpening that I will link below this video. most chisels and flat irons are ground to a 25 degree primary bevel which is not the final working angle which is just a shallow angle which removes most of the steel so you can ease in.

I usually use stones to create a microbevel at whatever angle you want to work with, but the hollow or concave surface created by a round grinding wheel complicates things a bit, while the facets in this drawing are exaggerated, it illustrates how a hollow ground bevel is made. many angles from heel to cutting edge, this can make setting up the tool holder a bit difficult. I won't mess around with all the geometry and math, the simple fact is the higher the contact point on the wheel rim. the shallower that part of the bevel is, so you need to take the thickness of the tool into account when setting up the tool holder.

A 25 degree setting for a smooth iron will not be the same as a 25 degree setting for a chisel because the chisel is a thicker tool which is why I don't like fixed angle tool rests some people find the differences to be arbitrary or close enough but this is the angle for a smooth iron and this is the angle for a thick chisel it's more than five degrees though both produce a five degree t bevel on their respective tools if you grind your smooth iron on the same setup as that thick chisel, you'll end up with a bevel closer to 30 degrees on your single iron or more, which means you can't sharpen a 30 degree micro bevel on the cutting edge, so I like to adjust the bracket of my tool for the tool I'm grinding instead of using one setup for all tools the setting process is pretty simple if you're just refinishing or repairing a bevel primary already set with the grinder off so you can turn the wheel by hand adjust the tool holder until it leaves scratches in the center of the existing bevel re-grinding the tool with the rest in that position will double the primary bevel angle original in that easy to use tool you can also use this scratch test technique to make adjustments to the primary bevel angle this is especially useful if your microbevel has become so wide that the original primary bevel is almost gone instead of doubling steepest micro bevel angle tilt the tool the rest of your scratches are closer to the heel than the cutting edge this will grind a shallower bevel on the tool in reverse if you want a s the tilt angle adjusts the rest to that the scratches are a little closer to the cutting edge, of course these are arbitrary angles, but there is no rule that says that the primary bevel of a tool TA should be ground to 25 degrees with this process, you can refine and adjust the angle a little at a time to suit your preference, but if you bought an old chisel that someone ground to 45 degrees or some crazy angle and now you have to redo it completely , how do you configure the tool support for that? you could start grinding the heel checking every now and then with a protractor or angle gauge until you get close to what you need or you could find another tool that is a similar thickness and already ground to the bevel angle you are looking for Use the scratch test on that new tool, then attach your tool holder and you're ready to race.

It's also worth noting that you can make setup jigs by placing a small block of wood on the back of a tool you've already ground. the angle you like cut most of the shape on the bandsaw and then let the wheel itself finish shaping the wood. These setting blocks will help you quickly reset your tool holder to double that angle later, but it will only work with tools of the same thickness and if your grinding wheel gets smaller with wear and coating, the template will become useless. and you will need to make another one so I think they are best suited for CBN wheels that are not made smaller where the basic tool grinding technique seems relatively simple but there is more to what meets the eye, the condition of the tool is an important factor of course if you are just restoring the original primary bevel angle you don't have to remove a lot of steel, in fact you have to be careful to only scratch the surface of the wheel especially if your grille is relatively thick so you don't remove too much steel and get a crooked edge.

I recommend a fine wheel for routine grinding somewhere between 220 and 350, you can use an 80 or 120 grit wheel if you like. re using your standard wheels but use a light touch so you don't remove too much steel at once and end up with a crooked edge of course if you have a lot of material to grind to repair a tool then 80 or 120 will be much more quick don't touch the wheel with the tool and then move it sideways, instead enter the cut with the tool that is already moving sideways, pull it over the wheel and keep it moving as you come out of the cut, back out last of each pass and restart the other way, if you hold the tool on the stone and just move it back and forth, you risk grinding unevenly for that fraction of a second every time you change direction again with light pressure , but even with light pressure you may find that you drag the back corner as you go. exit at the end of each stroke because the resistance decreases as most of the tool comes off the stone avoid dragging that corner try to keep your strokes even remember heat is your enemy but you also have several ways to combat the wheel type what you are using using ho how coarse the grit is how you keep your wheel the size and material your tool holder is made of with a light touch and dipping in water as needed all these things add up to protect your tool against overheating keep your fingers close to the cutting edge so you can feel the temperature rise as long as you can touch the steel it's not too hot if you can't touch it immerse it in water the danger zone when it comes to overheating is the cutting edge of the tool where the steel is at its thinnest when you begin to restore a primary bevel you will only work on the curing first, the edge of The cut will not be in the stone but after a few passes the primary bevel will come close to that cutting edge so keep an eye on the width of the old micro bevel do not grind it all the way leave a bit in place this will help prevent the Brittle cutting edge will overheat on the stone and by staying clear of the cutting edge you will also ensure it stays square whereas if you were to grind a All the way to the edge of the tool you may discover how easy it is to grind a crooked tool with an aggressive wheel, while the primary use of a grinder for tool sharpening is to restore a primary bevel with light strokes. a little extra work to completely reshape the tool, such as re-square the crooked edge or remove a chip if the edge is only slightly out of square, you can pay more attention to the high side of the bevel with which the moving tool will still enter the cut , but start the pass near the low side, then the next pass a little further to that side and so on as you work the bevel back checking frequently with your square the key to smoothing out a bevel is light strokes always keeping the tool in movement when in contact with the stone this takes some practice but not that difficult when the edge is square again, take two or three light passes even across the entire bevel to make sure it's right and even when polishing a brand new bezel, whether it's to repair a bent edge or to remove a chip or other major damage runs the risk of overheating r the thinnest part of the steel right along that cutting edge you may not even know you overheated it just wondering if it didn't stay sharp very long some choose to avoid the risk entirely by intentionally dulling your edge this can This may seem counterproductive but it produces some clear advantages, for one thing this is the quickest way to cut a Reese's tool or even grind a radius and curvature profile and the flat facet it creates on the edge can become a guide for help you make sure you keep the edge square if you angle the tool rest and start grinding the bevel again.

Keep an eye on that flat facet as you work, of course it will get narrower, but as long as it remains, you even know it. you are not removing too much material from one side or the other if the rapid gets wider on one side you are grinding the tool crooked and need to remove more material from the wider side to even it out continue to form the new bevel until that blunt facet is just barely visible, but don't grind it all the way down as you'll thin the steel too thin and risk overheating a small blunt facet on the end can be easily removed when creating your microbevel on your stones later if you'd like more information on honing with stones including creating micro bevels with straps and jigs and

everything

else, check out the links to additional resources below this video, wait, don't go yet if you're new here, subscribe and remember to ring the bell.

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