Sharpening confusion

[Bernie Vail]

Having just started turning, I find myself confused about sharpening turning tools. Everything I read, and all the DVDs I watch, says put an 80 grit wheel on your grinder and go directly to the workpiece. This contradicts everything I have learned about sharpening; I was taught that the finer the sharpening medium, the sharper the edge. I hone my plane blades, my chisels, my jointer knives, etc etc. I finish my chisels with an 8000 grit waterstone (they cut like crazy too!). I read the comments about turning difficult wood, and everyone says "sharp tools essential". Yet all the turners say "nothing finer than 80 grit". Can someone explain this apparent contradiction to me?

[Ryan Baker]

Sharper is better. That is still the case even with turning tools. But many turners find that the edge off a 80-120 grit wheel is plenty sharp enough to do the job, and it isn't worth the additional time and effort to sharpen and hone further. The turning tool edge is subjected to a lot more cutting much faster, and requires frequent resharpening anyway. A honed tool will cut better and last a little longer than straight from the grinder, but not necessarily enough to be worth the effort. Try it for yourself and decide which way works best for you. I use my turning tools directly off a 120 grit wheel, except for skews which get the full Tormek treatment.

[Ken Fitzgerald]

Bernie,

I use a slow speed grinder and typically use the 120 grit wheel. But that is just my preference.

Turning is much harder on tool edges than other types of woodworking because of the agressive nature of putting a somewhat stationary tool against a spinning piece of wood. As such, you expect to have to sharpen more often. Thus it doesn't make sense to most to take the time to go to the extremes of sharpening as you have been taught.

Once you are experienced sharpening, you can do it in a matter of seconds and return to turning.

That's my take on it.

[Brian Brown]

I always wondered about
this apparent contradiction myself. If you sharpen a tool to 8000 grit, the edge is so thin that it gets worn down very quickly, especially roughing wood. However, with highly figured wood, it is esential that the tools be scary sharp. So for me, I sharpen with a 120 grit wheel, until I get close to the finish part of the turning, then I step it up with the sharpening, and hone the bageebers out of my blades. :)

[Jeff Nicol]

Bernie, This is an ongoing question that really has no right or wrong answer. If you are a flat wood worker and you have used planes and chisels and carving knives where the blades should be polished and honed to a razor's edge, it is hard to believe that taking a tool from the grinder to the turning wood is the best way. What helps to make it make sense is that if you are roughing out a lot of items there is no need to hone the tool, as we know time is money! The edge off an 80,100,120, or what ever wheel you prefer will cut just fine for roughing. The main thing is to have a consistent grind without facets to cut even and cleanly. The only time I hone a turning tool is if I am using the skew a lot and need to make a very fussy little cut or when I am making the last very fine finishing cut on some soft or punky spalted wood. But then I take a smaller (1/4") bowl gouge and finish the cut at a little higher speed with a light cut,right from the grinder to the spinning wood. You will see that most all turners do the same thing, as honeing all the time is mostly a waste of time, but has its place when needed.

TO HONE OR NOT TO HONE......THAT IS THE QUESTION? Do what makes you happy!

Have a great day,

Jeff

[Gordon Seto]

Bernie,
I think you are right. Unless you can find a quick and efficient way to sharpen the turning tools to 8000, it may not justify the time in sharpening.

How often do you have to sharpen your hand plane blades? how many feet of planing?

For a 6" diameter blank at 1000 rpm, your turning tool will cut 1571 linear feet per minute, slightly under 1.5 miles in 5 minutes. The bark, dirt may be very abrasive and dull the tool very fast. You will need sharpening instead of just stropping with compound to hone.

If you prefer a finer tool edge, you can go with a wet grinding system, such as Tormek. It will produce a finer edge than dry grinder (not as fine as 8000), and at a reasonable efficiency. But the higher end tool steel for turning tools takes a long time to shape the first time.

In reality how fine the edge the tool has doesn't dictate what kind of finish you can get off the tool. We are holding the turning tools free hand, the undulating tool marks dictates what grit sand paper we can start using.
I have seen several professional turners demonstrated at our Club. They all used the same Club grinder. Some could start sanding at 220 or even higher, or no sanding at all. Some wished they could start at 120.

[Curt Fuller]

Sharpening a turning tool is sort of like sharpening a chainsaw. You can get it as sharp as you want, but it's not going to stay that sharp for more than a few seconds. You've probably read all the calculations about the speed that the perimeter of a bowl is traveling. Well, your bowl gouge gets several hundred if not thousand feet of travel across the wood in just a matter of seconds or minutes. It's going to take that fine honed edge off the tool in seconds. So unless you like to stop and sharpen every minute or so of turning you have to compromise and get an 80 grit edge that's quick and easy, use it until it gets dull, and repeat. But then as you get to the final cuts you want to get a fresh, sharp edge, maybe even do a little honing, and then make that last shear cut.

[Gary Herrmann]

I think Gordon nailed it. Using a plane, scraper or chisel, your cutting edge is moving at a snail's pace compared to what the edge of a turning tool is doing. Even if the wood on the lathe were clean and milled - just the amount of wood you're removing is going to wear the edge out faster, so imo, sharpening to 8000 grit isn't worth the time. Now for a final pass, I will make sure the cutting edge is sharp and often will hone it with a diamond paddle, but that's about it for me.

It would be interesting to see an experiment where a flat tool was presented to a board and moved at a speed comparable to a turning tool...

[Kyle Iwamoto]

If you don't like grinders, look into the Tormek. This place has a lot of discussions about dry high speed vs. water cooled slow speed. As mentioned before, there is no right answer. Speed vs. qualitiy of sharpness. If you firmly believe that sharper is better, then look into the Tormek. Yes it is more expensive, but if you're just starting to buy equipment, it not a whole lot more expensive that a complete dry grinding setup. I don't turn for profit, so time is not money for me. I can spend time sharpening my gouges. And you can use the Tormek for your regular chisels. It puts a hollow grind on it, your 8K grit stone will get it sharper than you ever thought possible. No need that secondary bevel.

Sorry for tossing in the Tormek into yet another thread.

[Burt Alcantara]

I agree with Kyle. I recently bought a Tormek because it would let me sharpen my kitchen knives, something that I've been unsuccessful with. Additionally, the Tormek jigs lets me sharpen other tools, especially garden tools which my wife is always after me about.

Yes, you could do this with other sharpening methods but the Tormek system lets me do this quickly, easily and repeatably.

I started with the Woodcraft slow speed grinder and a Wolverine. Had no problems getting sharp tools. But, couldn't get my kitchen knives and other tools sharp. Guess I'm a jig addict. Sharpening takes practice. Eventually, you'll find your own grinding profiles which will increase the efficiency of your tools.

The current "state of the art" is using a grinder anywhere between 40 grit to 120 grit. Newer technologies, such as carbide cutters where you don't sharpen at all, are beginning to emerge and will probably change the face of tool use over the next few years.

Burt

[Kyle Iwamoto]

Oh yeah, I forgot about the kitchen knives. When I asked the boss for permission, the initial response was, of course, NO. But when I said that I could sharpen the kitchen knives, I got the green light. Now when the knives get the slightest bit dull, I get complaints. I even sharpen all my relatives' knives.

Keeps the boss happy.....

[Bernie Weishapl]

Another vote for the Tormek. Kyle when I tole SWMBO that I could sharpen all of her kitchen knives and her scissors she said go for it. Of course her's has to be the first thing you do.

[curtis rosche]

when we say keep your tools sharp for some woods, it because if you are having fun, sometimes you forget to stop and sharpen and just push harder, which can end up in a nasty catch

[Dave Rudy]

Many good comments on this thread. I will add this: With a fresh sharpening from the grinder, a final push cut leaves a surface so smooth that honing would appear to be wasted effort.

The proof, as the saying goes, is in the pudding.


Dave

[Dick Sowa]

Gordon said it right. I did a turning presentation for my local woodworking club...mostly flatwork folks. I said the same thing as Gordon did..."Applying a tool to a 2” dia spindle, at 2,000 RPM for one minute, will cover nearly 1,000 feet!" If you tried that with a honed chisel or plane blade, you would be back to sharpening in mere seconds. I use a 100 grit wheel. Even for clean wood, I often will resharpen my bowl gouge several times before I am done.

[Bernie Vail]

Thanks to everyone for their replies. I think I understand better now the difference between the types of tools and their sharpening. I can get away with sharpening a plane or chisel once a month or so, but if I was using them as much and as harshly as I use a bowl gouge, it would be once every five minutes! :) No way I want to do that.

[Alan Trout]

I also use a wet grinder. Mine is the Jet and I use a combination of jigs some Jet for knives but my jigs for wood turning are Tormek. I really like how sharp the tools get and I have been real happy with how the system has performed overall. However with that being said there is a place IMHO for a slow speed grinder. The slow speed grinder is a much faster way to re-shape a tool if desired than with the wet grinder. It can be done on the wet grinder but just takes quite a bit more time.

Good Luck

Alan

[JerHall]

Few things are more controversial amongst turners than the value of hand honing your tools. The foremost advocate and modern practitioner of hand honing across the hollow of the bevel, and within the flute, between grindings is Alan Lacer who in his article Turning Tools and Honing makes the following case:

"Honing Guidelines for skews, gouges, parting tools: It is easier to keep a sharp tool sharp than it is to use a tool so long that you must return to the grinder. Get in the habit of regular honing, especially before final cuts. For gouges hone the outside ground bevel first by touching the heel of the bevel first, then gently rock into the area just below the edge, still touching the heel of bevel-always a two-point contact. Next, hone the inside flute: hold the curved edge of the slip stone perfectly flat within the flute and move the stone in and out of the flute until the entire edge has been honed. Hone both ground surfaces of the skew and parting tool in a similar two-point strategy. You can only hone a properly ground tool-grinding is still more critical than honing. Rule: Hone the bevel and not the edge!!"

See his article at: http://www.woodartbydan.com/articles/honing.pdf

I use a slip stone that I keep in my pocket and with practice takes about 10 seconds to refresh an edge. I often go hours without a trip to the grinder. Once the hollow grind is shrunk down so that honing takes too long I then go to the grinder to restore the hollow grind, and use a jig to get a perfect bevel and hollow.

Also see: Sharpening Lathe Tools: Basic Principles Lyn Mangiameli's classic on why honing can be of great value link here: http://www.morewoodturning.net/sharpen.pdf
He reports a test where the shavings produced from a honed tool were compared by weight to a non honed tool. You get a lot more production from a honed tool.

What it comes down to IMHO is how fast you can hone v. grind. Also tool life if you care. If you can hand hone in 10 seconds, or refresh an edge by hone on a wheel of some sort in the same time or less that you can grind, and don't waste all that steel why wouldn't you hone every time it was feasible? That is what many old time production spindle turners did.

That's my story and I am sticking to i! I doubt this will change anyone's mind, but you might try getting a $12 medium grit slipstone such as at:
http://www.woodcraft.net/family.aspx?FamilyID=236
and try it. At the very least it is essential for skew chisels and may be of use at demos and when you don't have access to a grinding setup you like.

[Jim Becker]

I use a 60 grit Norton 3X for shaping and a 100 grit Norton 3X for "sharpening"...and sharpen very frequently. In fact, most of my work is done with an Ellsworth grind and I have three gouges so that I pause less often for sharpening...but always go to the wheel right before final finishing cuts. This is for turning tools.

For flat work chisels and plane irons...I use water stones and go for a razor edge.

[Bruce Shiverdecker]

I use a Wolverine system with a 120 grit wheel. It's ok for now, but, since I'm cheep, I will wait till it needs replacing and get a 220. I believe that I will get a better edge.

Wood carvers also Hone their blades, I'm not sure that we would get that much benefit from the time necessary to do it. We have to re-sharpen our blades too frequently.

Bruce