Thoughts on Sharpening tools for Wood Turning

 Welcome to the turning world. 🙂 There is a sharpening concept I refer to as "grinder abuse". The idea is that if you make your tools from HSS (High Speed Steel such as M2, M42, CPM, etc.) you can grind the hell out of them and not worry about ruining the temper when they turn blue.

When working with "old school" tool steels (also called carbon steel) such as O1, W1, 1095 and so forth, one of the cool things you can do is heat treat in your home oven or even a toaster oven. At around 400°F your metal will turn a color called "Straw" the ever lightest of yellow/browns. This takes out the hardness just enough to keep a hardened blade from being brittle, like glass. That is wonderful. With any hand stone oil, water, diamond, CBN, etc.. you would be hard pressed to rub fast enough to ever reach such a temp and so you are fine. Nor, can you manually carve wood so fast that you would reach such a temperature, unless you were some weird super-hero in a Marvel movie. 🙂

In comes the turner. First of all when working with a spinning piece of wood, you are cutting miles of wood with your sharpened tool in minutes time, because you can. In doing so, even the hardest of metals will dull and need sharpening. If you use a single bowl gouge you will probably want to sharpen it about 3 times in the course of making a bowl. Perhaps more depending on size or the type of wood. Turning with a dull tool it an inefficient experience and it leaves a poor finish surface. So at the very least a turner will sharpen right before final cuts.

There is no reason this sharpening can't be done on a hand stone, or even diamond "credit card". many turners will sharpen one way, then "touch up" or "hone" their edge on a card with a few quick strokes and be satisfied.

However, like turning, sharpening is a skill that we are not born with. And, sharpening, unlike turning is not really sexy. There are fewer groupies tossing their undergarments at people for how well they sharpen than there are for people who turn out bowls and hollow form vessels. 🙂

So rather than an additional skill worth learning well, sharpening becomes a "necessary evil" like computer backups, and safety glasses underneath face shields. So, in order to require far less skill to accomplish a consistently edged tool, one learns to throw money at jigs and use a grinding wheel. However, a fast wheel, will easily get a piece of steel up and over 480° (brown) or even 575° (blue) at which point, you will either over harden (by quenching) or aneal (soften) the steel by letting it cool slowly. But not with HSS steels, they can tolerate up to "Dark Red" 1292°F so one doesn't even have to learn the skills necessary to use a grinder without overheating the tool.

At one point people may not have all adopted all HSS tools. Many of their existing expensive tools were all made of regular tool steels and had been working fine for years, so in order to make their lives easier, enter 2 things. Friable wheels. These are the pink, blue, white wheels, that shrink pretty fast because their crystal structure breaks faster causing there to always be a "sharp" edge on the abrasive and therefore cut faster and consequently cooler. Then add, slower wheels, which would allow the grinder to not create as much heat because of less miles of abrasive across the steel in the same amount of time.

Finally, (or at least in my experience so far) is CBN. These wheels use a metal wheel with an abrasive permanently attached thus keeping the wheel the same size for its lifetime. It also doesn't lose its abrasive, so all that comes off the wheel is steel dust. And the wheels themselves do not explode like the regular ones.

Adding to the whole mix the Irish grind. Or the Ellsworth grind. David Ellsworth used a grind that involved swept back wings and a reasonable cutting angle of about 62°. This allowed the same tool to cut both the outside of the bowl, as well as all the way down the inside of the bowl. I assume that as a traveling turner carrying one less gouge added some convenience to his life. Or possibly using the same tool for multiple jobs felt more efficient, or possibly any number of motivations. He is not a huge YouTube guy, and I don't own any of his videos or books so that is about all I know about the "why's" and "wherefore's" of the grind. But like most people today, I use it. When he started out I have to believe he ground it by hand/eye. I have done that, and though possible, it would take a bunch more times before I felt confident that I could do it consistently, but it would be very do able. He then came up with a jig that looked like a chunk of aluminum bar stock with a central hole down the middle and a wire stuck in it at 45° and decided that 7-4-2 would be the way to sharpen something to his grind. That meant having a pivot point 4" below the center of the wheel, 7" back from the wheel, and with the tool extending 2" from his jig.

This is all you need. However, I think his jig (complete with his name engraved into it is like $50, give or take). If you go and so some patent searches there are plenty of jigs and fixtures for sharpening turning gouges. Captain Eddie Castelin makes and sells one called Blackhawk. I have duplicated it and added some things to mine that I missed with his, and it is quite sufficient to get the job done, quickly and efficiently. A few other companies make such jigs/fixtures and there are even free plans online for maybe 4 different ones. However, OneWay up in Canada sells one called Wolverine and integrates Verigrind jig into their system. Their price is whatever it is, and the jig is variable so you can change angles and use it to invent your own grinds or whatever. Funny thing about it is that most people will tell you "Set it like this. Then never change it... ever." Which tells me that a variable angle is far from necessary.

Anyway, I have made my own of the variable angle ones as well.

I am not 100% sold on the benefits of the Ellsworth grind. If you watch people like Stuart Batty, or Cindy Drozda they use what is called the 40-40 grind and you generally don't need a jig to do that. Just a platform (tool rest) and a couple of sharpie lines to do it. I have used it and like it, but my mentor uses the Ellsworth grind, and so I follow until some point where I have enough actual experience to make a decision that takes me back to a 40-40 or possibly even something else, like the "standard", "common" or "English" grind... which I assume Allan Batty would use on a bowl gouge, though I have never really watched him do anything other than spindle work.

So the point is, you can sharpen any way you choose. Just make sure you have sharp tools. You can use a grinder at whatever speed you like, but you will have to regulate, either your technique, your media, or your tool steel to do so. Everything that adds convenience will add cost. HSS costs more than carbon steel. New tools cost more than used tools. Friable wheels cost more than AlOx wheels, and CBN wheels cost more than Friable wheels. A slower grinder costs more than a faster one, and it just keeps going on down the line.

Do what you are able with what you have at hand. If a project takes longer because of some manual technique, then learn to enjoy that technique and make it part of your hobby. That way, when you are spending 3 hours in the shop to make a bowl instead of 2 you are still enjoying 3 hours of a hobby. You might decide you enjoy sharpening more than you like turning. Might even want to make a business of it. Same with turning, though you might want to turn for profit. When your goals switch from enjoyment to business, you now have to evaluate the cost of your time. But when you get really good and people just have to have your stuff, then you hire an apprentice to do all the sharpening, shop sweeping, blank making, photography, sitting at trade shows, and the stuff you hate about your beloved hobby as a business.