Sharpening of tools

[ziggles]

Has anyone finished sharpening their tools on a stitched rag wheel with the grey paste. The grey paste is for removing fine scratches from metals such as stainless steel. Currently i use a 120 grit white wheel and then use diamond stones to sharpen, but i can't remove the hairs off my arm. I was hoping this method might be easier on bowl gouges.

[DJ’s Timber]

You shouldn't need to go any further than the 120G wheel, it's not really worth the effort as it will be bluntened fairly quickly on the lathe

[scooter]

Gday ziggles, you don't need to hone your goues to that degree, most turners use the tool straight off the grinder, & even then more commonly use a 80 or 60 grit white wheel. Shaving sharpness is not needed.

Skews are one of the few turning tools that is honed to a better finish than the wheel alone provides.

Save the zealous sharpening for plane & chisel blades.


Cheers...................Sean

[Cliff Rogers]

Yeap, agree, honing is for carvers & darksiders, use the force Luke.

[Alastair]

Hi All

In addition, 'soft' surface sharpening like rag wheel can tend to round over the edge unless you are careful.

I find that sharpness off the wheel is more than adequate for most turning. For particularly keen edge on skew, or to 'freshen up' a gouge between grinds, I use an oilstone or slipstone by hand.

A

[Skew ChiDAMN!!]

I dislike pushing brand-names (except, perhaps, for turning chisels! ) but for touch-ups or honing I reckon you can't go past Eze-lap diamond stones.

[rsser]

Ziggles, are you talking about turning tools or bench tools (chisels, plane irons etc)?

[ziggles]

I'm talking about turning tools. At the moment i use the wheel to get the hollow grind. At the club here they have taught me to only use the grinding wheel when the point and the back of the hollow flatten to a straight edge. Yes i use the eze lap diamond stones to keep it sharp between grinds. if i turn mango and camphor laurel its fine. but when i turn a harder timber it takes a lot more effort and blunttens the tools quick. If i have sharper tools to start with i won't be tearing the grain but slicing it cleanly.

[Skew ChiDAMN!!]

I'm talking about turning tools. At the moment i use the wheel to get the hollow grind. At the club here they have taught me to only use the grinding wheel when the point and the back of the hollow flatten to a straight edge.

Good advice!

If i have sharper tools to start with i won't be tearing the grain but slicing it cleanly.

It's a subjective thing.

The problem is, the sharper it is the quicker these same "hard" woods will blunten the edge. There comes a point when it's just not worth it. IMHO, even just 30 seconds of honing to get an edge that'll only stay sharper than one fresh off the wheel for 5 seconds is effort wasted.

So it boils down to where you draw the line. A production turner would just shake their head over the whole concept and move onto doing something more rewarding. If you have the pleasure of leisure and can take your time, it's a different matter. So the question becomes "do you think the results are worth the effort?"

BTW, a good technique makes just as much difference as a sharp edge, or rather a bad technique will blunten chisels as quickly as turning concrete. There are also many different ways to make any cut, some are more effective than others at different stages. So that's where I'd be spending my time if I were you; at the lathe instead of a grinding station. The nice thing about developing good technique is that once you've obtained it it's more permanant than the fleeting glint of steel on the end of a chisel.

[derekcohen]

I hone my lathe chisels on a 240 grit disk sander. A gentle touch, 2 seconds, and they are razor sharp. Just ask Wild Dingo.

Regards from Perth

Derek

[rsser]

I would add that with gouges it does help to polish up the flute with a slipstone from time to time - an edge being the intersection of two planes.

Some gouges come from the factory well polished (like Henry Taylor) and some look like tram tracks (P&N).

To amplify Skew's point: there are woods like Brush Box with a high silica content that will do in any HSS edge in under a minute, so don't always assume your tool was starting out inadequately prepared.

[Toolin Around]

Deleted as it was pure drivel and the tone sucked

Let try restating it in a more civilized manner...

Before I came here I was a production turner, artistic turner... Pretty well have done it all - not bragging it just is. I like everyone else did the same thing, I ground a tool and went straight to the lathe with it. But as a carver also I knew the benefit of an extremely sharp edge and began adapting the sharpening techniques to my turning.

If you don't believe me try this test. Take any bench chisel you have - doesn't matter the quality. Now find a medium density piece of wood. Grind the chisel to your usual bevel angel. Then pare off a few shavings taking note of how hard you have to push the tool down and with (down isn't the same as pushing with it) to get a cut going. Also note the angle you have to put the chisel on to get it to bite. Last brush your finger against the grain and feel the surface. Now hone that chisel with a 1000x stone and repeat on another part of the same piece of wood - note the results. Now hone it to 6000, repeat again noting the results. Now regrind, hone to 6000 and buff the bevel side well and just brush the flat side to remove any microscopic wire edge edge (or if you have lignums wood disk with buffing compound - just as good except you can't do inside curves). Take note of the differences from all other methods. You will notice that the chisel, relative to the other methods, is almost effortless to pare off shaving; to the point that it's almost too effortless. The tool will grab the timber at nearly any angle without the need for any downward pressure. The only angle it probably wont grab at is 0. You should also note if you used a hard enough timber that the purely ground edge got harder to use with each cut where has the honed and buffed ones didn't. Also depending on the wood used (I've found blue gum does this when carving) you might notice that the end grain hasn't sprung back from being slightly compressed by a "dull" edge that doesn't cut absolutely clean.

You're probably thinking this is a bench chisel it doesn't apply to a lathe chisel. I can't state it any more plainly - it does matter. The only difference is you're allowing a machine to do most of the work spinning the wood. In fact it matters more because in one turning you will encounter all types of grain at every angle - sharp tools are an absolute to over come this. These principles of sharpness apply to every edge tool in woodwork except scraping.

As a production turner these principals are magnified a large amount, especially because it all takes place at speeds over 2000rpm. Never had the guts to exceed 2500rpm though. There were times when a real stringy air dried piece would let go but the chunk was still held by the main piece and would come back around and wrap my knuckle 10 times before you even had a chance to react. Or an exceptionally hard knot would just exploded bouncing sharp shrapnel off my head and chest. Then you look down at the tool and the tips completely gone. Once in awhile a knot will get you on the hand and cut you up pretty good.

Having to go back and forth to the grinder burns up way too much. A buffed usably (very important term here, it may feel sharp on the skin but we're not talking about cutting meat and veggies here) sharp edge would last at least 3 more legs than a purely ground edge or 5 post caps (that can mean an extra 15 minutes turning). If I hit a large knot (which was very common) the ground edge was dead on the first contact with it. And it wasn't just a touch up that it would need, the edge was not chipped but it was blunted real badly. Where as the buffed edge ploughed right through and left a nice surface; a buffed edge could take on usually 2 big knots (2" dia) before it was completely dead. It was very important that the edge be durable enough to absorb the punishment of a knot. If it tore it up the leg and the time to turn it was lost - a buffed edge left me with far less failures.

A usably sharp edge right off the grinder would last about 2/3s as long as a buffed edge. If I have a stock of timber with a lot of knots that can add up to an extra 30mins or more standing in front of the grinder. To buff took no effort at all. Walk to the buffer, turn on, push flute of (or back of chisel) tool hard against buffer for five to ten seconds depending on the flute size, check for dull spots - done. Grinding entails getting the bevel rubbing nicely on the wheel then moving through the needed motion to get the edge back. I don't know how anyone could think that buffing would be slower. I would grind at the beginning of the day (help to get myself into a rhythm) and then once every 10 or so buffs. Which depending on the quality material being turned meant I only grind once that day. There is also a cost savings as well. Every time you grind you loose about .25mm. When I buff I may loose .05mm. Ultimately saving what may amount to a penny a day is irrelevant.

The effort to push a ground edge through timber for eight hours a day was extremely noticeable no matter what it was. Where as a buffed edge needed little or no effort to start and push through and allowed me to take very deep cuts and not feel wrung out at the end of the day.

A keen edge will make tools more versatile. What I mean by that is, the more times you have to change tools in production turning the more time you're loosing. The oak pedestal is done mostly with a 1 1/4 roughing gouge. You just can't carve out that shape with a purely ground roughing gouge - it too dull and the rolled back wire edge from grinding (even the best wheels leave a rolled back wire edge) just doesn't allow it. Buff the flute and it will peal the shaving off in all sorts of ways you wouldn't think of.

Same with post caps if the edge was extremely keen I could do the balls in one pass. I never found the purely ground edge was up to that sort of work with out a lot of effort. Most times it just wasn't up to it.

The principle of a sharp edge apply to all woodwork whether hobby or professional. The failings of technique though are much more magnified in an intense situation such as production turning. They may not be nearly as noticeable for you but they are still present. So why not know what they are - it'll only improve your turning.

Even as an artistic turner these principles apply. If you like doing very intricate work especially with very hard and brittle exotics you know the wood can be very fragile as you come to a knife edge. A purely ground edge in such turnings is far more prone to breaking off some end grain simply because it take a fraction more pressure to get the edge cutting. Where as a buffed edge (remember the chisel test) will start and cut with far less effort which means there is less backward pressure exerted on the support wood as you move through the cut.

You should also notice that the overall finish left by a buffed edge is better than a purely ground edge (remember the chisel test). Splash water on the wood and see which has more raised grain after it dries. Some will argue that they get a great finish off a ground edge. But as many turners have written in their books it's because the pressure exerted by the bevel on the wood is burnishing it. That's what I call a false finish cause all you have done is squash the fibers down so that they appear to be a good surface. The same thing can be done with a rock if you're so inclined - but I don't think most are going to do that. A truly good surface is cleanly cut leaving a nice glossy finish and after the water test has little raised grain compared to the purely ground edge. Everyone knows what a board is like to work with after it's gone through a planer with really dull blades. The fibres are pounded down making working with it a chore - same applies to woodturning. But if you like sanding then it's no problem.

Hope this makes things a bit more clear.

[Gil Jones]

80 grit pink wheel to form an edge or change an angle.
120 grit pink wheel to sharpen woodturning tools.
The only woodturning tools I hone or diamond lap is the skew,
and usually not even them.
I feel that lapping/honing is a waste of time for a turning tool,
but hand carving gouges and plane blades are another matter.
I do agree with Toolin that a good buffing (I use medium gray Stainless Steel Polish) gives a very fine edge, and is as fast (or faster if you are set up for it) as regrinding every time. Saves steel too.
"Your mileage my vary"

[Skew ChiDAMN!!]

Buffing is superior, anyone who says otherwise has never put it to the test.

I stand by what I said... for me the result isn't worth the effort expended.

Maybe I've been lucky cause I've never read any how to woodworking books and therefore have made my own discoveries instead of relying on some "expert" to steer me wrong. I drew my own line so to speak.

Ditto, mate. What I state are my opinions and my findings. I don't quote out of books... I'm too bloody lazy. Instead I'll say "go read such'n'such."

As for the "expert" part... who do you think I am? Darlow?

I don't know what it is about sharpening threads but they sure get me going.

Yep. Sharpening should be deemed in the same class as politics and religion.

[rsser]

Don't think any of us have all the variables pegged.

Wood, type of tool, quality of tool, application of tool, pace of application, etc.

They all vary and part of the game is about recognising and responding appropriately.

Yes, there are some rules but unless you specify all of the above, well it's your experience. Terrific. But that's all it is.