Why CBN, or other coated steel wheels are not as good as a a matrix grind wheel......

Discussion in 'Woodturning Discussion Forum' started by odie, Apr 19, 2014.

  1. Mark Mandell

    Mark Mandell

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    You Left Out . .

    "And I slept at a Holiday Inn Express last night" [copyright]:D:D
     
  2. Jeff Deutschle

    Jeff Deutschle

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    If it takes 4 minutes to hone, then it was not ground properly, or if this is a touch-up while turning, it needs to go back on the wheel. I haven't used a stop watch, but I would say that it takes less than 1/2 minute to hone with most of the time spent picking up the stone, oiling it, wiping up the oil and setting it back down.

    I have been thinking about how when turning a bowl with a figured grain you are not just turning across the grain, but against the grain, too. If you want the minimum amount of tear-out, you need a super sharp edge that can take the lightest of cuts. Sure, there is no need to hone with shaping cuts, but there is a place for honing for finishing cuts. You can't sand tear-out effectively.
     
  3. John Nesmith

    John Nesmith

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    Pretty much.
     
  4. Jeff Deutschle

    Jeff Deutschle

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    Yes, I think so too.

    One gentleman in our club goes to "Totally Turning" every year. He said (and I believe him) that he watched the big name demonstrators get ready for the day and they ALL sharpened freehand, without a jig.

    Hmmm, so which would be more "like the pros", using a jig or not?
     
  5. Mark Mandell

    Mark Mandell

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    I ain't no pro (turner, that is) but the only time I use a jig is when I'm shaping (or restoring) a profile. Especially on the 180 CBN, I use the rest for my hand and just kiss the edge while rotating the profile by hand. Of course it may be a bit easier for me since I use a convex bevel for everything except the skews.
     
  6. Sergio Villa

    Sergio Villa

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    Generally I read and post to learn something. At this point of the discussion I learned that many like the CBN wheel, many sharpen freehand, many use jigs, many hone their tools many do not but very, very few are big kissers.
     
  7. hockenbery

    hockenbery AAW Advisor Staff Member

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    Jeff,
    Small sample size......
    I would suggest just about all the professionals can sharpen by hand.
    Many do use jigs at least part of the time.
    Many do not.

    I will grind my bowl gouges without using a jig if the wolverine tracks are misaligned.
    Al
     
  8. Richard Findley

    Richard Findley

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    I've been reading this thread with interest, and 2 things have struck me...

    1- How many people hone their tools. As a production turner, I take my tools straight from my grinder (120g White Wheel) (sharpened freehand from an adjustable platform)

    I used to use a little slip stone to remove the small amount of burr that you naturally get from grinding/sharpening (whatever!!) but it was pointed out to me by several more experienced production turners that as soon as you touch the tool to the wood, that burr is gone, so why waste your time? I haven't honed since. This mostly refers to spindle work with gouges and skews, but I don't hone my bowl gouge either and don't have any problems.

    2- I've not yet heard mention of using a belt type grinder/sharpener, such as the Sorby machine. I assume that has made it over there by now, it having been on the market for a number of years. They seem to be growing in popularity over here, just wondered if they are something used or considered over there?

    Cheers

    Richard
     
  9. Richard Findley

    Richard Findley

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    Just to add a little more regarding honing. I know of a few turners that grind their tools then hone until they can't hone any more and the tool regrinding. The main reason I have heard given for this is so they don't waste steel. The way I see it, once you have the grind you want, each sharpen is just cleaning the bevel, so minimal steel is lost. Really don't see the point myself.

    My white grindstone is around 5 years old and has lost about 1" of diameter, most of my tools last several years before needing to be replaced, even those in daily use. This suggests that either I am good at sharpening, or I don't sharpen enough....

    Richard
     
  10. odie

    odie

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    Hello Richard......glad to have your input!

    I think you're right that more turners don't hone, than those who do......don't know if that's an accurate assessment, but it's my general feeling from the input I've read. I also believe it's all a matter of the kind of results that are desired, combined with the skill of the turner to take advantage of a finely honed edge.

    There are others who have stated that they do not hone, because the burr is gone almost immediately. The tool will certainly still cut. The problem with this is the little burr is a piece of metal that is still connected to the cutting edge. When it breaks off, it does not break off without leaving a broken edge. This might be a matter for further discussion, but the edge that is left after the burr has broken away will surely still cut. It all depends on what is acceptable, but probably few will disagree that a carefully honed edge will produce a better result than an edge where the burr has broken away. Well, I can't speak for others, but this particular point is something I have experimented with, and my findings are the honed edge will produce the superior cleanly made cut. The down side is the carefully honed edge will not last very long, but while it is still viable, it does exceed the possibilities without honing.

    The Sorby sharpening belt system has been available here for a couple years, that I know of. I haven't heard much comment from those who use them. If it's your opinion that the Sorby system is better than a grinding wheel, I'd be interested in hearing about why you feel so.

    ooc
     
  11. Brian McInturff

    Brian McInturff

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    I really do laugh at these discussions. No right answer. No one is right and no one is wrong. It's all about what works for you. Do I hone? Sometimes.
    Quick question for those that hone religiously. How many revolutions does a honed edge last? Do you hone when the honed edge is dulled? Just curious if anyone is honing every 20-30 seconds. Oh? So it really comes down to................. Personal preference. Guess that's why I hone, sometimes.
    I also believe CBN wheels could scientifically be proven to have advantages over matrix wheels. With every revolution of a matrix wheel there is microscopic loss/wear to that wheel. This loss won't be uniform so it has an effect on the surface being sharpened. The CBN wheels do not have this issue. Most people dress their matrix wheel when it's noticeable to the eye(otherwise they would have to dress it every use. I could go on....
     
  12. Richard Findley

    Richard Findley

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    Hi Odie

    The funniest thing about all this is that most people have their opinion and are sticking to it, making this slightly pointless, but a bit of fun all the same ;-)

    The thing with sharpening is that there is always some sort of compromise to make. You can hone to the point you can shave with it but if that lasts for only seconds then it's pointless. You need to get the balance between sharpness and longevity surely??

    As for the belt sharpening system, the only reason I brought it up is because if this debate was happening on a UK forum someone would have chimed in by now that it's a better option. Personally I haven't tried it but it certainly appeals... Apart from the price tag!! You get a flat bevel (which many claim is better) there's no risk of stones exploding and you can buy various belts down to quite fine grades for those that are anal about their sharpening!

    Cheers

    Richard
     
  13. john lucas

    john lucas

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    Richard I've been playing with belt sharpening as well as using the Tormek and Matrix wheels and the CBN just so I can learn what the pros and cons are of each. I use a 320 belt on my sander right now although you can change belts in 30 seconds or less so you can use whatever grit you think that tool needs, even a strop. A 320 belt cuts fast. Hard to put a number on it but I'd say it's not far behind my 120 grit matrix wheel and my 180 grit cbn. It fact you have to be very light on the tool when sharpening or it becomes shaping real fast. You get a really really clean cutting tool off the 320 grit. The edge looks as polished as the edge off my Tormek which is supposed to be 1000 grit. I'll probably have to get a microscope to really learn the difference.
    What I don't like so far is the belt gets dull fairly quickly. I can't find the Blue ceramic belts in higher grits so I'm using a standard wood sanding belt. Still the belts only cost $3 and it just takes seconds to replace. I haven't replaced it yet because it's still working but also haven't used it a lot since I'm only sharpening 2 tools on it.
    What I'm learning from all these sharpenings is that it is all so subjective. I can get a clean cut with any tool I pick up if I use it correctly, straight off the grinder or not. I do get a cleaner cut from a freshly sharpened tool that has been honed with a 600 grit wheel, but is it sharper than belt at 320 or the Tormek at 1000. Hard to say because every piece of wood I turn is different. Kind of like saying my Particle metal tool edges last 4x as long as HSS tools. I think they do but without putting some kind of scientific test with hard results to it I really can't say that they do. I stop to sharpen hopefully before a tool gets dull but then what is my definition of dull and I'm sure it varies depending on what wood I'm cutting and how I feel today. :)
    So as you said this is an interesting discussion ( a little long winded at times) and we probably aren't going to change anyones mind. I sharpen both free hand and with a jig. Both have advantages for me depending on the tool. I do sharpen more free handed when I travel because I often don't have access to the same jigs I use or their set up is just not the same as Al hinted at.
     
  14. Jeff Deutschle

    Jeff Deutschle

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    Yes, certainly, it comes down to (winds up being) - personal preference. Hopefully this personal preference is based on personal experience in light of others personal experience. That is the value of this forum.

    The other day I rough turned a bowl from ash heartwood from a sort of crotch on a power lathe. I did not hone. The next day I worked on a flower made from green lilac, that needed to be about 1/8 inch thick to prevent cracking while drying, on a treadle lathe. I did hone. (Went through the bottom with a scraper, sigh...)

    As far as dressing my wheel, again personal preference, I dress it with a little crown. Actually, when I dress the wheel I am really just getting the residual metal off of it. I also prefer a 6 inch wheel and have looked around for a 6 inch CBN. But then I am just a hobbyist, and use my grinder for general shop use. I really don't want to get a dedicated grinder for lathe tools.
     
    Last edited: Apr 23, 2014
  15. odie

    odie

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    Mornin' Richard......

    You are right about strong opinions, and those who have them are not likely to change their point of view. I offer another opinion about whether or not opposing points of view are a worthwhile discussion. There are many new turners here, and among those, opinions are still flexible. From my perspective (believe it or not!) there have been times when I have changed, or altered my views. I'm sure I'm not the only one who has. On the discussion at hand, I doubt that will happen because my views here are the result of years of experimentation and adjusting the methods I have come to find the results I am having. Admittedly, I do not bother to buy every new product that is touted as the best thing ever, but I do have a perspective gotten by time and practice using the tools and equipment I have.......

    Back in my very beginnings, thirty something years ago, I did use a 4x36 belt for sharpening tools. There, the belt changes were slow, and the belts didn't last as long as I'd wanted. I guess none of this really applies, because I was such a newbie back then. My first grinder was 3450rpm with 6" wheels. This is when I bought my first SG wheel, and have stuck with it because this wheel is dramatically better than anything else (an opinion!). For quite a few years, I didn't hone much at all, but slowly graduated to the methods I have evolved to today......because of the results I am capable of. Tool preparation is a major factor in my evolution, but by all means, is not the only factor......

    ooc
     
  16. Duane Meadows

    Duane Meadows

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    Sooo true! Kind of reminds me of some of the Neander/power tool threads I've read.

    Although having a wealth of information available is a good thing, it can also make things even more confusing for a newbie. What do you believe among all the conflicting info available. Even though one turner(or even several) get excellent results from a method... Does that mean it is the easiest to learn or the best method available? I think not always!

    But that perspective is somewhat skewed if you have not tried the other options, no?


    Or at least better than what you had! Doesn't make it "the best" available. It is one thing to say my way works, but quite another to say it is better than something one has not tried! I've been in that position many times.. thinking I,ve found the best way since sliced bread, only to be shown I am working way to hard!


    I am sure tool prep is part of it, but even the sharpest tool possible, presented to the work piece improperly, can result in very poor work or much, much worse!

    I try to keep an open mind, and when I find something that may be better than what I am currently doing, I like to at least give it consideration. Do I buy every new thing that comes along? No, of course not. But if everyone took the attitude that my way is best, innovation and thus progress would come to screeching halt!

    Odie, I have seen many of the pictures you have posted. Your results are undeniable, and I like your work. This has been an interesting, even entertaining thread!
     
  17. Jeff Deutschle

    Jeff Deutschle

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    "Does that mean it is the easiest to learn or the best method available?"

    That really jumps out at me. It depends on what you want to accomplish. Do you want someone to be able to produce a doo-dad with very little experience, or do you want someone to learn how to really use the tools and methods that are available? Just the mention of a skew brings shivers to most of the club, for instance. And there are some members that use every tool as a scraper. I think they could do better... And yet if I was to get a youth interested in turning I would start with scrapers. Then introduce other tools and various methods, including sharpening, depending on their interest and abilities. I think it is important in every craft to keep it challenging.
     
  18. hockenbery

    hockenbery AAW Advisor Staff Member

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    You have some interesting points in your post.

    IMHO people have to work up to the best methods available. Beginners should be taught the fundamentals with the gouge Anchor bevel cut... Using the push cut. A shear cut with a gouge, most often the "best method available for hollowing a bowl" is something best learned on top of a solid foundation. The fundamentals always come into to play. But they are far from the best methods available. I consider many uses of the scraper to be and advance skill too.

    Too many turners take pride in ignorance of the skew like some folks take pride in ignorance of arithmetic.

    So true. In workshops and other activities I see folks using the side ground gouge only as a scraper. They are missing the beauty of what the tool can to. And in some cases they think they are accomplished with the tool.

    My experience with youth is they get the use of the gouge quite quickly even as young as 8. If a kid can slice a tomato unattended they can master the spindle gouge in 1 spin top.
     
    Last edited: Apr 23, 2014
  19. Duane Meadows

    Duane Meadows

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    Sharpening with a CBN wheel doesn't mean that you can't hone the edge if you want to.

    Nothing discourages new turners more than trying to turn with dull tools. If jigs and CBN wheels make sharpening easier to learn, I see nothing wrong with that. In fact I see advantages to both. As with tool technique, a few fundamentals are necessary. Then we build on those fundamentals. Same as with most(all?) hobbies or professions for that matter.

    Sharpening is a subject that I am very interested in, and still have a lot to learn. I still do it with matrix wheels, but definitely think CBN is in my future. But I think sharpening fundamentals are way more important than what type of wheels I use. Of course there is a need to use wheels that are compatible with the type of steel your tools are made from. But beyond that if it works, it works.

    Don't laugh, but for some time I did most of my sharpening with a buffing wheel/buffing compound. It worked, what can I say!
     
  20. Bill Boehme

    Bill Boehme Administrator Staff Member

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    They're here, but sticker shock has probably kept most potential buyers at bay. Most of us aren't too prone to toss out our sharpening system just to buy something else that can do the same job for more money.

    Or, you can sharpen on the grinder to the point where it will cut wood but if that only lasts for minutes then it is pointless. :rolleyes: (something that a beginner might say)

    Since wood is anything but a homogeneous consistent material it is good to keep our sharpening options open. The longevity of an edge may not be the most important consideration when dealing with challenging conditions in wood.

    I know some turners who have used a belt sander, but Richard is referring to the new Sorby belt sharpening tool which is not a belt sander. It is very expensive on this side of the pond and the belts are very expensive and they do not resemble sanding belts at all. I have seen them at Rockler Hardware and at Woodcraft. Most of the various woodturning catalogs also have them. Here is a link to the Robert Sorby Pro Edge at Craft Supplies.
     

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