Bowl gouge sharpening techniques are really the first thing that needs to be learned when turning wood bowls. Why? Because without a sharp bowl gouge turning wood bowls is not easy.
As the saying goes, “An almost sharp bowl gouge will almost cut wood.”
Another reason bowl gouge sharpening techniques need to come first is, depending on the cuts and type of wood, the bowl gouge will only stay sharp for so long.
I had an opportunity to see this play out first hand. My brother, who lives about a thousand miles away, had just acquired a small bench lathe but had no tools. He wanted to turn some bowls.
When we went to visit him, I threw a couple of my gouges in the car to bring along. Long story short, we got one small bowl made before the gouges were too dull to continue. Without a sharpening system, we could go no further.
Being fortunate enough to do my initial wood turnings at weekly group gatherings, I started without any equipment. As I learned the importance of a sharp bowl gouge, my equipment acquisition order was easy to determine.
My bowl gouge sharpening system was the first piece of equipment I put into place in my shop. I did this even before I owned my first bowl gouge.
How It Works
When we sharpen a bowl gouge, we are not doing anything other than restoring a sharp cutting edge to the bowl gouge. Over time, that sharp edge gets dull as we turn.
The area of the bowl gouge that needs attention is the bevel. The bevel is the flat area that wraps around the front and sides under the sharp cutting edge.
When we employ the bowl gouge sharpening techniques, we are smoothing and leveling the surface of the bevel. At the same time, this action restores a sharp, crisp edge between the bevel top and the bowl gouge flute.
The corner where the bevel top and flute edge meet is the business end or cutting edge of the bowl gouge.
Bowl Gouge Abuse
While turning a bowl, it’s easy just to forget the stress on the bowl gouge. However, let’s look at this from a different perspective.
What if instead of working a nice compact round of timber, the bowl gouge was drug across a long continuous surface? Imagine, sitting on the tailgate of a truck going down the highway and holding the bowl gouge tip against the road.
Depending on the size of the bowl blank and the time spent cutting, your bowl gouge actually accumulates MILES of cutting time. Too bad there’s not a frequent flyer program for bowl gouge miles turned.
If you’re good at math, you can pretty quickly run some numbers. The circumference of an 8” bowl blank is 25.12”. If the lathe is turning around 800 r.p.m., the bowl gouge will travel a full MILE about every three minutes.
That’s an amazing amount of cutting and performance from a piece of steel. It gives me a new respect for the durability and performance of the bowl gouge.
When To Sharpen
There are several indicators that a bowl gouge needs sharpening. Some of these indicators include; time, temperature, and results.
When the gouge dulls, performance also reduces, friction will increase. One sign of a dulling bowl gouge tip is heat. If the tip or end of the tool feels warm or hot, it’s time to practice your bowl gouge sharpening techniques.
Another great indicator of a worn down cutting tip is performance. Yes, performance problems effect bowl gouges too.
The quickest way to tell is if the bowl gouge produces chips or dust instead of longer shavings. Keep in mind some woods don’t make nice curly shavings, but in general dust and chips are a good indicator of the need to sharpen.
And the third best way to know its time to sharpen your bowl gouge is your memory. Can you remember when you sharpened last? If you can’t remember when you last sharpened, it is now probably time to sharpen or past time to sharpen.
Always remember this wood turners joke, or perhaps a truth. “If you think your gouge needs sharpening, you should have done it ten minutes ago.” In other words, keep on top of your bowl gouge and sharpen frequently.
If you are experiencing heat, poor results or if you can’t remember, it’s time to sharpen.
What Angle To Sharpen
When we go to the grinding station to sharpen this is not the time to reshape or change the angle of the bowl gouge. So, for now the cutting angle of the bowl gouge will be the same as it currently appears.
Changing and adjusting bowl gouge sharpening angles is covered thoroughly in another article, be sure to check that out.
I do encourage experimenting with different bowl gouge grinds and angles, but that is a much broader topic covered in other articles. Here, we will focus on our bowl gouge sharpening techniques.
Setting the Wolverine VariGrind Jig
Depending on the bevel angle and length of the bevel side wings, you will need to adjust the Wolverine VariGrind Jig accordingly.
Essentially, the angle of the leg sticking out from the bowl gouge holder adjusts the amount of side wings created while grinding jig extension arm position adjusts the front bevel angle.
We will be making adjustments that match your bowl gouge’s current front bevel angle in step five below. The front bowl gouge bevel dictates the distance the jig is from the sharpening wheel.
The thumb screw on the jig controls the side profile or side-wings of the bowl gouge. This angle can be adjusted to create shorter wings or longer swept back wings.
I sharpen my bowl gouges with long swept back wing profiles. The swept back angle gives me more cutting surface to remove more material quickly. I can also flip the tool over and use those wings for shear scraping cuts to smooth a bowl surface.
Learn to perfect the shear scraping cut and your bowls will improve dramatically.
Swept back wing is my preference. Your bowl gouge may have a completely different grind, and profile and that is fine. We are here to understand bowl gouge sharpening techniques, regardless of angle or profile.
The ultimate goal of sharpening is to maintain a continuously smooth and sharp cutting edge consistently. Each time we go to the sharpening wheel we want to be consistent.
To achieve consistency, I strongly suggest using a sharpening jig. I use the Oneway Sharpening System with the Wolverine VariGrind jig to maintain consistent sharpening angles at the wheel every time. See my Recommended Sharpening Equipment guide for further details.
Yes, it is possible to sharpen by hand at the grinding wheel. However, this takes a lot of practice and skill. I admire those people that can hand sharpen efficiently and consistently.
Because only a small amount of bowl gouge metal needs to be removed to restore a sharp edge, I don’t want to risk slipping and necessitating additional grinding. The more you grind, the sooner the bowl gouge is reduced to a stub.
Using the grinding jig is simple, quick, and very efficient. When done correctly and frequently, sharpening with a jig only takes a few seconds and is accurate every time.
The results from using a sharpening jig are consistent and repeatable. These are the two main key factors that make the bowl gouge ready to turn efficiently every time.
Here is my complete guide for setting up and using the Wolverine Vari-Grind Jig for consistent bowl gouge sharpening results.
Bowl Gouge Sharpening Techniques
Here are the bowl gouge sharpening techniques step-by-step. Keep in mind these steps incorporate the Oneway sharpening system to produce consistent and repeatable results each time.
1) Position the bowl gouge in the jig with the pointed leg of the jig facing backward and down. Tighten the thumbscrew until it is snug against the flute of the bowl gouge.
2) Using a depth gauge jig, Set the exact length of bowl gouge extension from the jig and tighten the thumbscrew completely.
3) With the grinder off, loosen and adjust the sliding jig holder extension.
4) Place the leg of the bowl gouge jig into the extension arm end holder.
5) Slide the extension arm in or out to position the front center bevel of the gouge flush with the surface of the grinding wheel. Tighten the extension arm lever.
6) Take a marker and color the surface of the bowl gouge bevel.
7) With the bowl gouge held out of the way, turn on the grinder and let it get up to speed. Once up to speed, make light contact with the bevel area that is colored.
8) If the colored area appears to have an even stripe ground through from the top to the bottom of the bevel, all is ready to continue to step 10. If, the strip is only partially across the bevel continue to step 9.
9) If the top edge of the bevel is ground but not the bottom, loosen the extension arm and move it inward a very small amount, just a hair. Lock the extension arm and make another slight contact with the wheel, go to step 8. If the bottom edge of the bevel is ground but not the top, loosen the extension arm and move it outward a very small amount, just a touch. Lock the extension arm and make another slight contact with the wheel, go to step 8.
10) Using smooth fluid movements, roll the bowl gouge bevel across the surface of the sharpening wheel from left to right. Try to keep the sharpening area of bowl gouge in the center of the sharpening wheel on the grinder. Also, attempt to give all areas of the bevel the same amount of time against the sharpening surface.
11) After only a few seconds of moving the bowl gouge bevel across the sharpening wheel, remove the gouge and closely inspect the bevel and cutting edge. If a smooth, shiny bevel appears from heel to cutting edge all the way around, you have a shape edge. If you see any rough spots or interruptions in the bevel smoothness return to step 10 and repeat until the bevel is smooth in all locations.
Be Precisely Precise
The most critical aspect of bowl gouge sharpening techniques is to be consistent and precise. Our bowl gouge is a highly effective tool vital to the whole bowl turning process. We need to treat the bowl gouge accordingly.
Each time we go to the sharpening wheel we need to make sure the bevel is exactly flush with the wheel. Even being off a hair will cause issues eventually.
Think about this for a second. If your sharpening angle changes a quarter of one degree, barely noticeable, each time you sharpen it will add up. Do that four times, and your bevel cutting angle will change a full degree. Do that forty times and, now your bevel angle is TEN FULL DEGREES different from where it started.
Take your time, use the marker on the bevel trick to confirm the bowl gouge is indeed flush with the grinding wheel each time. This simple step is worth the effort.
The time you take being precise while sharpening will pay off in a couple of ways. Your bowl gouge bevel angle will be consistent and you will remove less metal making your gouge last longer.
Sharpening is not grinding; we are here only to sharpen. Using the bowl gouge sharpening techniques, each time at the grinder you should just be removing a thin amount of material from the bevel of your gouge.
If you find yourself needing to spend a long time sharpening and making the bowl gouge bevel smooth again, you may need to sharpen more frequently. Stop more often and sharpen less is better than waiting and needing to sharpen a very worn gouge.
Ideally, each approach to the grinder should take a couple passes across the bowl gouge bevel surface and only require a few seconds of time. As soon as the bevel is shiny, flat and even, the gouge is sharp.
The coloring of the metal at the tip of the bowl gouge might occur if you’re sharpening too long, with too much pressure or both. We do not want color to appear on the steel of our bowl gouge.
Colored metal indicates that the gouge shank is overheating and that causes stress within the gouge. Colored areas need to be removed and this requires slow patient grinding, not necessarily sharpening.
If you feel the heat, preferably before you see any brown or blue start to appear at the sharpening tip of your gouge, stop sharpening. Let the gouge cool a bit. Go sweep shavings or take a break because your gouge too needs a break.
Quenching Hot Metal
You can cool the bowl gouge by dipping it in water to quench it while sharpening. However, and this is important, DO NOT quench or cool the gouge if it colors or overheats.
I had to get an explanation about quenching directly from a bowl gouge manufacturer in England to confirm. Here’s what I learned.
Like so many things in this wonderful world of woodturning, there are opinions, ideas, and facts. And usually, those three don’t always mix or play well together.
Previously among other turners, I was told, “Yes you can quench high-speed steel (and cryogenic steel) in water while sharpening.” Only later to be told quite emphatically by others, “NO! Do not quench gouges while sharpening. You will weaken the metal.”
So, which is it, Yes or No?
The answer is both. Of course, the answer is both! I love all the variables in woodturning! Ha!
Here’s how it works. You can quench and cool the metal as you sharpen if the metal does not get excessively overheated and/or discolor. It is safe structurally for the metal temperature to be reduced with water if the temperature is within reason. Quenching needs to happen frequently and which keeps the metal temperature within a narrow range that doesn’t get overly hot.
On the other hand, cooling a bowl gouge that is overheating and discolored will result in too great and dramatic of a temperature shift which can damage the internal structure of the steel. Dramatic heat shifts in the steel can cause the tip of the bowl gouge to chip, shatter, or break potentially.
The best way to avoid all this is to sharpen nice and slow and easy. Make quick light sharpening passes on the grinding wheel letting the wheel do the work, never press hard into the grinding wheel. Then there is no reason to stress about the metal stress in your bowl gouge.
At first, bowl gouge sharpening techniques may seem daunting and headache inducing. After a few times at the grinding wheel, the entire process eases and the bowl gouge sharpening techniques become old habit.
Take your time, sharpen frequently and with precision and your finely tuned bowl gouge will reward you with beautiful wood bowls time and time again.
Other article on sharpening to help you out include:
• WOLVERINE VARI-GRIND JIG – ILLUSTRATED GUIDE
• BOWL GOUGE SHARPENING ANGLES – SURPRISE ANSWER
• VARI-GRIND JIG SETUP ONEWAY WOLVERINE SHARPENING SYSTEM