bowl gouge what to buy

Discussion in 'Newbie' started by Charles Hill, May 19, 2013.

  1. john lucas

    john lucas

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    I think you and I are talking about 2 different things. I'm not talking about sharpening angles, only the length of the bevel that is the edge. If I sharpen my gouge with one angle I have a bevel of say 3/8" that goes from the tip to the lower corner of the bevel. If I remove much of the metal from this bevel so that I only have 1/8" of the original bevel, I get exactly the same cut. That's what I'm trying to describe.
    In drill bits or metal cutting bits this is often called a clearance angle if I have my definition correct. In a drill bit you have a very short main bevel or cutting edge and then it's ground off behind this to give you a clearance angle. That is essentially what I'm doing with my bowl gouge.
    Hope that clears it up.
     
  2. MichaelMouse

    MichaelMouse

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    The edge will always be as long as the bevel, being created, as they are, simultaneously. So I guess I'm not catching what you mean. Are you trying to describe one technique used to solve the problem of the cylindrical gouge, that of grinding the heel for clearance, leaving the original sharpness angle for cutting? If so, the first being unchanged, the cut will be unchanged as well.

    http://woodcentral.com/newforum/grinds.shtml Are you talking about relieving the heel like the Ellsworth or Fairfield examples, or the Kauder (Hunnicutt #3) approach, working backward toward a traditional grind?

    Here's what I'm working with. http://i35.photobucket.com/albums/d160/GoodOnesGone/Bevels.jpg Thickness similar, therefore longer bevel creates a more acute sharpness angle which shaves better.
     
  3. john lucas

    john lucas

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    Yes I'm talking more like Russ's grind than Davids. You'll notice Russ has ground away much of the bevel below the main bevel. I will have to take a photo of my wider spindle gouges to show you what I mean there. My point is it's the cutting edge that does the work, not the bevel. I learned early on to remove the sharp corner from the bottom of the bevel to prevent bruising of the wood. The triple bevel like Russ (and I) use is just a variation on that.
     
  4. hockenbery

    hockenbery AAW Advisor Staff Member

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    I agree on the cutting edge doing the work.

    A shorter bevel has two advantages: less bevel drag which can be a real help on thin pieces and
    It allows cutting a tighter radius.
    Ellsworth and others grind the heel off the bevel to shorten it which you mentioned earlier.
    This allows turning a deeper bowl before hitting the rim with the handle.
    The triple bevel is much the same thing.
    It also creates less be el drag which makes it easier to turn thin without chatter and to work further off the tool rest without chatter.

    Johannesen Michelson, a master of thin has a micro bevel at the edge of his grind virtually no bevel drag.
    Extremely advantageous on a flat or gently curving thin surface where a long bevel would have a lot of contact and drag.

    When turning a convex shape it doesn't matter too much because just a tiny bit of the bevel contacts the wood.
     
    Last edited: May 30, 2013
  5. MichaelMouse

    MichaelMouse

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    I take it, John that you're using something like the first pictured grind here? http://www.woodturningvideosplus.com/bevel-angles.html As mentioned, one of the first workarounds for the cylindrical gouge, it kept the same sharpness angle - therefore the same optimum cutting pitch - as the unrelieved heel version. My "bowl" gouges are ground similar to carving gouges used to dig and waste material - no heel at all, so no drag. Of course, if you have ANY clearance angle at all you don't drag, heat or bruise. But you have to get away from that vision of a line of contact perpendicular to the edge as "the bevel touching" and realize that parallel to the edge, with a bit of skew, shaves cleaner and with less resistance.

    Large sharpness angles as Al advocates, produce more resistance because the pitch angle has more of a push than peel vector. Makes it, In my estimation, less preferable to a more acute sharpness angle, where there's more slice than scrape. I exploit the phenomenon not only to escape a grade or two of paper on cured wood, but to keep from pushing the ears out when turning wet wood interrupted edge pieces. Keeps me from having to use a scraper, a skill which I never really developed. Though I do increase the pitch angle to turn an abrupt corner, scraping more than slicing as I do. Since i keep the shear in, I suppose you might call it "shear scraping."
     
    Last edited: May 31, 2013
  6. hockenbery

    hockenbery AAW Advisor Staff Member

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    You can have a lot of different experiences with a side ground gouge. If you use it like a traditional ground gouge you just have the large cutting angle.

    When discussing the Sharpness angle of side ground gouge it is important to note that the bevel angle changes.
    The Ellsworth grind on my 5/8 bar diameter bar bowl gouge. The bevel angle varies from about 50-60 degrees on the nose to about 30 degrees on the leading edge of the wing. When used in a shear cut, a slicing cut, or pull cut you have the advantage of a sharper 30 degree bevel angle. These cuts cut more at an angle to the wood giving a cleaner surface. When used in the roughing cut you have the beef and stability of the nose and the sharp cut from the wing.

    With the Ellsworth grind used in shear cut mode flute up cutting on the front edge of the left wing you get more of a vertical slice.
    That cut can be made from rim to bottom center of a natural edge bowl and leave a surface for 220 sanding.
    This has almost no pressure on the bowl.
    It is an advanced cut and takes some learning.

    I still use other tools with other grinds from time to time but for open natural edge bowls I only use a bowl gouge with the Ellsworth grind and spindle gouge to cut the tenon for the chuck and final finish cuts on the bottom when reverse turning. Anyone who uses the Ellsworth well on a natural edge bowl can usually start sanding with 220.

    Have fun,
    Al
     
    Last edited: May 31, 2013
  7. john lucas

    john lucas

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    I agree with Al. I use 2 gouges in the flute up position. My Stewart Batty grind on a Henry Taylor gouge and my own special grind on a U shaped off brand gouge. the wings on the U shaped gouge are really sharp, something like 25 degrees. Used in the flute up position on a push cut and it gives me a very clean cut with almost no pressure on the bowl. Not a cut for the timid. You have to be very comfortable with your gouge because it takes very subtle movements to control it.
     
  8. hockenbery

    hockenbery AAW Advisor Staff Member

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    Flute up cuts belong on the "intermediate" board.
    It is a cut I have taught often to intermediates when teaching or assisting in classes.

    like John said the student has to be comfortable and have good control of the tools on basic cuts.

    I think it is difficult to learn without hands- on-instruction.

    I think it is a cut that once you have done it A few times it is easy to repeat, but if you tense up it will cause catch.

    It can be done with most side ground gouges to finishing the inside of a bowl
    On a cut rim bowl you need to roll into the cut inside the bowl
    On a natural edge bowl you can pick the cut up at the rim.
    Th interrupted cut won't cause the vertical gouge to skate.
    On the outside a flute up finish cut can be done with an English ground gouge.

    It can be very dangerous to do these types of cuts improperly.
    Roll the tool to much or sete tool rest below center and a big catch can happen.


    Al
     
    Last edited: Jun 1, 2013
  9. MichaelMouse

    MichaelMouse

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    Flute up sure can remove stock quickly. John posted a video where he slides the nose and cuts below it with a modest up angle. I consider that a safer cut than sliding the side doing the cutting against the work, because it's easier to control a possible roll. Those who grind their gouges at a constant angle on the wing gain a bit of stability over those who roll to more acute sharpness angles, but there's still the problem of a small cylinder that rolls fast to either side of the contact line perpendicular to the edge while trying to "ride the bevel." I ride the nose and undercut when hogging, but it's inherently less stable than using the nose section. Like aircraft, the more maneuverable grinds are also the least stable. http://s108.photobucket.com/user/MichaelMouse/media/HollowTwo001.mp4.html The nose begins and maintains as the tool swings.

    It's finishing cuts that cause all the "catch" complaints we see. (NEVER take that "last" cut.) Which can be easily remedied by using a different tool - specifically, the one used before machining technology gave use the cylinder to fiddle with. http://s108.photobucket.com/user/MichaelMouse/media/CherryPeelIn.mp4.html Those who look will easily see that the clearance angle on this tool is pretty high until it gets near the bottom in this piece. Deep pieces are just the opposite, using low clearance angles increasing at the bottom. The tool is what the side cutters try to get, but can't seem to maintain as they try to maneuver the handle around the rest, the banjo or the ways. It has full support from the rest, and is proof against catches because it curves away from work above the cut, and has a consistent bevel with no place to roll. http://i35.photobucket.com/albums/d160/GoodOnesGone/Gouge-Curves.jpg

    At least two of the many experiences available to users of side grinds. Both of which come with caution. Alternative three has neither. Don't let the name "bowl gouge" limit what you use. A gouge is a gouge just as in carving, and the broader sweep allows a broader naturally smooth cut than a narrow. So put the broad sweep on the end of the stick, not the side when you make the last cuts, and capitalize on control and a broader footing.
     
  10. hockenbery

    hockenbery AAW Advisor Staff Member

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    Michael,

    A shallow gouge can get a catastrophic catch. It should not be recommended to a novice unless you are by their side guiding them.

    A bowl gouge catch is limited by the flute once the wood hits the bottom of the flute the gouge can't go it any deeper and a chunk of wood breaks off. The Shallow gouge won't stop feeding in until something breaks. The gouge, tool rest, or banjo may break. Devastating injury can happen.

    You use the tool safely. This does not mean a novice will use it like you do even if you tell them clearly how to use it.
    They are going to grind it differently, present it differently,

    The down side of injury and damage to equipment with the wide spindle gouge outweighs any percieved benefit.

    consider deleting the post in the interest of Safety.

    The Gouges shown below should not be used on bowls. Their flat bent construction is considerably weaker than the machined bars used in bowl gouges.

    thanks,
    Al
     

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    Last edited: Jun 2, 2013
  11. robo hippy

    robo hippy

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    I never cut with the flutes up. The tool is unbalanced, and if you get up on the wing at all, it will tip over into the wood, and you have a spectacular catch. This is the most common reason for gouge catches. I always roll the tool over so that the flutes are at 45 to 90 degrees. This leaves the nose at a high shear angle for a cleaner cut. The advantage of the more open fluted gouges for finish cuts is that they have a larger sweet spot for the best cutting angle. They should also be used like a skew where you cut with the lower half of the tool edge. If you go to the high side of the tool, it is unbalanced just like a standard gouge with the flutes more vertical. They make lousy roughing tools in my opinion, but to me, that is what scrapers are for. Traditional SRG use is taught as gouge at right angle to the wood and spin, flutes up, start by rubbing the heel, and raise the handle, tipping the cutting edge down till it starts cutting. Yes, this is a bevel rubbing cut, but raising the handle even a tiny bit more makes you come off the bevel, and with spindles, this is generally not a problem, but on a bowl, if you do this, you turn the tool into a scraper instantly, and since the scraper in this case is directed up into the spinning wood, you get a catch. Those I see using a SRG on spindles, that I think really know what they are doing, will keep the tool at a 45 degree angle to the spin, and flutes rolled at 45 degrees or so, and cut like you do when you sharpen a pencil with a knife. This leaves a smoother finish cut on spindles and bowls as well. The tool is not inherently dangerous on bowls, how you present the tool to the wood is what makes it dangerous. This is true for all turning tools, there is a right way and many wrong ways to use every tool out there.

    robo hippy
     
    Last edited: Jun 2, 2013
  12. hockenbery

    hockenbery AAW Advisor Staff Member

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    Excellent advice for this area of the forum.
    I agree that every tool can used badly. That is why we all encourage people to get some good hands-on mentoring.

    Once we become proficient at wood turning we can turn spindles with an axe head and bowls with sharpened spoons.
    We don't suggest those tools to beginners.

    I has been my experience that the bad things with a spindle roughing gouge on bowls tend to be much, much worse than the bad things with bowl gouges.
     
    Last edited: Jun 2, 2013
  13. KellyDunn

    KellyDunn

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    Turning with the flute up is an advanced cut. The sweet spot varies for each kind of grind. A point on the gouge gives almost no sweet spot. Where a rounded tip with the wings ground almost straight up give a huge sweet spot
    That said it takes practice to do and I reccomend some hands on. What is considered a standard grind in the catalogs is a good one for this. I saw Ray Key in 86 doing this cut with no explaination. I went home and ripped a bowl off the lathe. Thats when I started turning the gouge upside down. There is a learning to every aspect of turning. Even with many thousands of bowls under my belt I still get some trouble spots. When in a hurry its easy for me to get runback when making the transition from the rim to my inside first cuts. All user error. But when paying attention or using a 1/4 in detail gouge to get me that first 1/16th down then all is fine. Or pushing the grind limits. Even I run out of bevel on a curve and try to push it a few cuts more when I should just grab another gouge with the proper grind for what I need to do.
    And everyone here who is saying get some hands on is giving the best advise there is.
     
  14. MichaelMouse

    MichaelMouse

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    You are kidding, right? Is there anyone else who can't look at the tool in use in the material provided and see that the tool CANNOT roll with the constant grind angle on the nose, and the natural curve of the tool extending into air? There's nothing to catch on, and a roll is impossible. I think you need to evaluate the material presented, and perhaps try the technique instead of attributing a break due to some horrible mistake in your past to the tool rather than the operator misunderstanding how to present ANY tool, much less the safest choice.

    I note that the skewchigouge and the fluteless gouge are catching on (not just catching ) with some turners now. Even with all that metal ground away up top, there's still a heel to limit the pitch angle. No such with the forged types. Makes them the tool of choice, as I see it. Recommend they be used under centerline inside as well, to take advantage of the air above.

    As to the fiction of a catch being limited by hacking out a chunk, it's obvious you've never thought much about it, either. Or read about people catching so hard they stopped their rotation. Besides, if it were true, then any tool, even misused, could never harm anyone, because the wood would give before metal buried itself or broke.
     
  15. hockenbery

    hockenbery AAW Advisor Staff Member

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    Not kidding a bit you are going to get someone seriously hurt.
    That tool should not be used by a novice. too dangerous!
    Tool is not meant for bowls and will break when used improperly on bowls.

    Your technique is just fine. You get results you are happy with.
    The whole point is it works for you because you have the skill and know how to present the gouge.

    Any properly presented gouge won't roll, go somewhere on its own, or catch.

    Novice turners will roll the tool, swing the handle the wrong way, grip the tool so hard it doesn't present to the wood properly.
    Novice turners can't control the tool like you do. We were all beginners once and I did not start with advanced techniques I built up too them.
    Any one who does exactly what you do will get similar results but it is not suitable in a newbie forum.

    You have obviously haven't taught very much woodturning or you would understand
    That yes indeed someone who has just seen the correct way to do something will go to their lathe and do it all wrong.
     
    Last edited: Jun 3, 2013
  16. robo hippy

    robo hippy

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    If you watch beginners closely, you will notice a lot of things that they will do that make no sense to some one who knows better. One problem with any demo is remembering long enough to get back to the shop and not be at square one again.

    robo hippy
     
  17. hockenbery

    hockenbery AAW Advisor Staff Member

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    Just human nature at work.
    Everyone has a different base to build on.
    I find one of the most important things when teaching beginners is to tell them a little bit at a time.
    It is easy to overwhelm them to where they can't absorb the important parts of the lesson.
     
    Last edited: Jun 4, 2013
  18. dbonertz

    dbonertz

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    How often do you get mesmerized by watching the shavings slide of the gouge? I, at times, am just enjoying turning and making shavings that I don't watch the top of the bowl for form. I watch the cutting edge. Then I snap out of it and pay attention to the form. I say this because new turners/students are often times watching your cutting edge and are in awe. They are not paying attention to your stance, body movement, hand movement, rolling the tool, body position in relation to the cut being made and etc. etc. They see the shavings fly and believe they can do it. At some point they realize to watch everything but the cutting edge work. Now they are ready to learn.
     
  19. Robin Thompson

    Robin Thompson

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    That was the question. Kinda of intimidates a newbie to the point where they don't ask to begin with.
     
  20. Dean Center

    Dean Center

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    Boy, ain't that the truth. I can't count the number of times I've seen somebody do something, or even had them show me how to do something, and 2 or 5 days later at home, I can't remember quite exactly how they did that but it seemed like they had the...BLAM! Another bowl bites the concrete. I've helped teach high school students over the last year and almost every day, Al's warnings have been reinforced.
     

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