Tool Edge Micrographs

Discussion in 'Woodturning Discussion Forum' started by Jeff Gilfor, Jul 22, 2014.

  1. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Woodturners seem to focus on two things when it comes to their tools (besides brand) -- the sharpening method and the steel alloy. What they really are looking for is how long will a sharp edge last and how is that related to how sharp an edge can be achieved with any given sharpening method. Neither of those question has a quantifiable answer, so there is the perpetual search for a substitute answer that that will satisfactorily scratch that itch.

    If I understand the question that John is hoping to answer, I believe that information is already readily available for any tool/HSS alloy, but unfortunately not as a neatly packaged for woodturning consumption type of answer. The data that describes the characteristics of these various alloys would only serve to give the average woodturner a case of acid reflux after trying to digest the data. Just to increase the level of heartburn, for any given alloy, the method of tempering has almost as much impact on the answer as does the minor variation between different alloys in woodturning tools.

    The good news is that nobody longs for the "good old days" when carbon steel was the sum total of our choices. Being overwhelmed with options is actually a great thing when you think about it. So, toolmakers, "keep on whelming us". Somehow, we'll get over it.
     
  2. hu lowery

    hu lowery

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    the truth about testing

    The multi-million and billion dollar companies can't do perfect testing. The best we can do is make the test reasonably relevant to what we are doing and acknowledge that it isn't 100% accurate. Been there with my own bosses years ago, a design worked on paper. I told them it wouldn't work in the real world, too many variables we couldn't model on paper(in the computer) that robbed efficiency in the real world. Been tried plenty of times before, didn't work. The company president wanted to move ahead. We did, just like everyone before us, we found the design didn't work!

    The tests and photographs will give us more information to interpret. How well we interpret the information will determine it's value.

    Hu
     
  3. Jeff Gilfor

    Jeff Gilfor

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    My head hurts.
     
  4. Mark Mandell

    Mark Mandell

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    Yo, YOU started this! :D

    Seems your neat pix have gotten upstaged by John's test parameters (Oh Oh He said "meters"). Didn't realize you'd stepped in something, eh? It may squeeze up 'tween your toes, but it will wash off.:D:D
     
  5. Sergio Villa

    Sergio Villa

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    Thank for your photos but... That a tormek sharpened and hone edge was better than a CBN or any other dry grinding was obvious.
    As far as serrated edge I agree with a previous post. It cuts faster and so does a chain saw with is usually sharpened with a file.
    It all depends what you want to achieve.
    Rough turning = serrated edge is ok. Final turning dry gringing is OK if you have a lot of sand paper. Wet grinding with honing if you want to start with a fine sand paper.
    In any case many factors related to the tool and the wood influence the cut, which is what really matters.
    The peed of the lathe, the pressure of the tool, the speed and steadiness of the tool movement, the type of wood etc, etc, etc. furthermore for checking an edge probably a scanning electron microscope would be better than an inverted microscope and this better than a regular microscope.
     
    Last edited: Jul 30, 2014
  6. Dale Miner

    Dale Miner

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    I usually check the edge with the callous on the side of my thumb. If it feels dull, to the grinder and return seems to fix it.

    I buy bowl gouges for the flute shape first, and the hoped for abrasion resistance second. The micro graphs are interesting though, and may shed new light on the abrasion resistance of the various steels.

    It seems like Alan Lacer did a pretty substantial study along these lines a few years ago.
     
  7. Bill Boehme

    Bill Boehme Administrator Staff Member

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    That genie won't fit back in the bottle.b Might as well forget about trying and just enjoy the twists and turns. :)

    Woodturning is so simple and yet so complex -- steel, tempering, sharpening methods ...... Just a machine that spins a piece of wood and a person poking it with a sharpened instrument -- from there, it's an endless list of complicating factors.

    And, it's so addictive that we form clubs, national organizations, internet forums, publish books and journals (not magazines, mind you) and have national and regional seminars. Some of our ilk are so talented that they achieve the equivalent of rock star status and some of us enjoy making dishes for Fido, but we all enjoy it immensely. Because of that, we discuss minutiae ad infinitum and share knowledge and then wonder if we are doing art or just making wood shavings. Regardless of the answer, we keep doing what we are doing.
     
    Last edited: Jul 31, 2014
  8. Gretch Flo

    Gretch Flo

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  9. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Grant, there are lots of ways to tell if your tools are dull. You mentioned pushing too hard, but it ought to be if you are pushing with more than a few grams of force just to get the tool to start cutting then the tool is dull. With a little more experience and a sharp tool you will find that all the force necessary can be done using nothing more than two fingers of one hand at the back end of the bowl gouge handle to guide the cut. If the tool is sharp, the cut will be clean and you will get shavings. If the tool is dull, you will get tearout and dust. Taking the extra time to sharpen when needed is faster than pressing on with a dull tool.
     
  10. Grant Wilkinson

    Grant Wilkinson

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    Thanks, Bill. I understand that.

    I re-read my post and realized that it added absolutely nothing to the discussion, so I've deleted it. I appreciate your advice, though.
     
    Last edited: Jul 31, 2014
  11. Bill Boehme

    Bill Boehme Administrator Staff Member

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    That's OK and don't worry about posts that you feel may not add anything to the discussion. I wish that I had a nickel for each of my posts that didn't add anything to the discussion. I hope that my reply wasn't condescending. Not knowing the skill level of another turner, I tend to provide too much information rather than not enough.
     
  12. Grant Wilkinson

    Grant Wilkinson

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    I did not take your post as in any way condescending, Bill. My deleted post was off topic and I killed it for that reason alone.
     
  13. john lucas

    john lucas

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    I think I've decided to just do a real world test on edge holding. I think ill turn some miniature baseball bats. It won't be very scientific it may tell me something when we look at the micro photos. Ill turn with the car on steel tool until it feels dull Then turn the same number with the other two. Hopefully the photographs would te something. I would try to turn with the other two until dull but that would be really really subjective unless one was far superior to the other which I doubt
    Talked to my sharpening guy yesterday. I send them to him in a oboist a week. They sharpen knives for a fishing tournament and will be too. Hey this week
     
  14. Jeff Gilfor

    Jeff Gilfor

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    Okay, my head is no longer hurting. It's been a tough week at the hospital. Boss is on vaca, and I'm the designated stand-in. This is why I don't like being in charge!

    Anyway,

    Next I will do micro graphs of all the tool sharpening methods again, along with something to show scale.
    AND (tell me if this makes sense), I will photograph a piece of wood cut with the tool in bevel rub mode. Then, I will use the tool for a set amount of time to continue cutting (let's say 2 minutes at 750 rpm), and will rep holograph the same two items (tool and wood).

    What say you all?
     
  15. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Is this like the YouTube video?



    John, I played the oboe when I was in Junior High, but lost interest because playing in the orchestra wasn't cool. I wanted to be in the band because playing-some loud shiny brass horn off key at football games was cool.

    So, you have some uncool oboe player as the go-between?
     
  16. Gretch Flo

    Gretch Flo

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    I didn';t make much sense of John's message, typos/ ( figured out car was carbon, but rest left me mystified) Gretch
     
  17. john lucas

    john lucas

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    Typing from my phone because I'm away and sometimes auto correct will do strange things. I'm also not very good at using the little magnifier that's lets you do corrections.
     
  18. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I know what you mean. Typing a message is hard enough, but correcting and editing is totally exasperating.
     
  19. robo hippy

    robo hippy

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    Hey, these threads wouldn't be nearly as much fun if they didn't go off topic. I asked, but don't think I got an answer about how worn/broken in the CBN wheel was. So, now to add to the formula, what would a micrograph of a brand new vs a well worn CBN wheel show???

    When John mentioned turning some base ball bat, I started thinking about several cylinders of the same diameter, and hooking up a gravity feed type pull, with the tool on a rail or slide.... All cuts the same distance, same diameter, same wood, same feed rate.....

    Yea, I know, I am making it more complicated.... that is the engineer side of me that I inherited from my dad.....

    robo hippy
     
  20. Robert Elliott

    Robert Elliott

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    Your dream systrm

    How about a modified duplicator? Driven by two syncros controled by an Adreno. You can monitor the control: feed rate, rpm, travel speed, current draw on the liner axis (tool drag), thermister on the tool for temp., an endiscope attached to the tool holder for video.

    Then you have imperical data to crunch. If you synk the video camera' audio trak with the rpm input to the Adrion to create a click track you would a visual record too. = total data.

    To me the hard part is making the tool tip holder.
     

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