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Thread: Machining wood versus hand planing for tonal quality

  1. #1
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    Machining wood versus hand planing for tonal quality

    Good day all,

    I was just sitting here thinking about tonal qualities of wood- you know, the sort of thing most people think about early in the morning ;-). I have this amazing single piece of WRC that was cut in the early 70's (not by me) and is big enough for a single piece top for a classical guitar. It has over 30 growth rings per inch and rings like glass when you tap it. I have been waiting for the right moment, as well as for me to develop my skill, before building the "Tonemeister."

    While thinking about tonal qualities of wood, I also was thinking about sharpening molding plane blades. (Stay with me here- this will come together.) I was thinking about how when sharpening on a machine, I have to worry about the heat generated, which we all know can change the metal's hardness. Then I thought about when you machine wood. It generates heat- enough to burn the wood if not careful. I started to wonder- could heat change (ever so slightly) the crystaline structure of the aged sap in the wood, thus changing the tonal qualities? I'm not talking huge changes here- I am talking concert guitar for a tone nerd who can hear silent dog whistles and tones other normal people can't hear.

    I thought I'd see what others thought about this theory.

    Cheers,

    Malcolm

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    I guess I should clarify that I am suggesting that using hand tools could be BETTER for tonal quality than using power tools- in the ever-so-slightest way.

  3. #3
    This is the kind of thinking, if done by 25 people or more that makes conferences that move the guitar as a stringed forward by zero. This is the kind of speculation that creates experts who have no way of proving their theories but are nonetheless wexperts. If you machine wood and generate enough heat to melt "sap" then you need to change your blades and move on. You are not dealing with the molecular minutiae, simply ignoring the fundamentals of woodworking.

    Build as light an instrument as you can that will play for 30 to 40 years and you have built a guitar worth building. One that responds to the minimal string energy that it has and amplifies it as much and as honestly as it can.

    Luthiers are pragmatic, hobby guitar makers are dramatic. Please feel free to tell me how you can hear two hand padded layers of shellac under lacquer comapred to vinyl sanding sealer under said same lacquer.

    Build honestly and you will make a fine instrument, no amount of theortetical conjecture replaces solid execution. Remember that for the most part people want an instrument that sounds like something from 50 to 100 years ago, you ain't inventing, you're replicating.

    I'm not brow beating the OP but certainly trying to be pragmatic. Stick to the well worn path and you'll be successful, cryogenically treat your spruce top and you're missing the point. Might as well sell your soul to the devil for divine tone a la Robert Johnson.

    See you at the Cross Roads.
    Last edited by Chris Fournier; 06-07-2014 at 8:31 AM.

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    Sounds like you already sold your soul to the devil. It was just a curiosity. Thank you for your colorful response.

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    Nah,he's just passionate!!

  6. #6

    Lost soul

    I may have but it wasn't to build the perfect guitar!

    If you use the classic materials and build well your guitar will sound great and as anticipated. I don't doubt that you've done so already!

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    Actually I grew up in Mississippi and know where the crossroads are where old hwy 1 meets Hwy 61. I play a lot of slide blues. For that I prefer a crapped out cheapie rusted resonator.

    Anyway, it was meant for coffee table type discussion, not world problem solving. The thought came to me as thinking about woods for the guitar and also thinking about sharpening on the grinder.

  8. #8

    Coffee table talk

    Quote Originally Posted by Malcolm Schweizer View Post
    Actually I grew up in Mississippi and know where the crossroads are where old hwy 1 meets Hwy 61. I play a lot of slide blues. For that I prefer a crapped out cheapie rusted resonator.

    Anyway, it was meant for coffee table type discussion, not world problem solving. The thought came to me as thinking about woods for the guitar and also thinking about sharpening on the grinder.
    It would be interesting to know about the heat generated at the cutting edge when machining wood but boy would that be difficult to truly quantify. In metal working they say that a properly set up operation puts most of the heat into the chip. I wonder if WWK'g is the same?

    A resonator's nasal tone always makes me pay attention, I really enjoy that sound.

  9. #9
    I don't think heat is a big issue when machining wood unless the feed speed is too low. It is easy to over heat the steel while making the knives or sharpening them, even with the coolant flowing over them it's easy to burn the common cheap
    grade of semi HHS while using the hard detail wheels to make the sharp corners etc. With the real HHS,usually only gotten by up charge and demanding it by grade, the same amount of heat doesn't spoil the knife.

  10. #10
    It's an interesting idea.

    Might even be a way to work out testing it (cut two book-matched pieces of wood by hand, then plane each down to identical dimension, one by hand, the other w/ a machine), but the problem is even the double-blind tests which I'm aware of are inconclusive --- music is fundamentally an expression of emotion and spirit, which is a hard thing to unambiguously test for.

  11. #11
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    Are you using air dried or KILN DRIED wood(already subjected to heat)?

    This is one of those threads where we are debating how many angels can dance on a pin head. I mean,really,how hot do your tools get? I haven't noticed in 50+ years significant heat in wood coming out of a thickness planer. Maybe if you let the knives get as blunt as butter knives.
    Last edited by george wilson; 06-10-2014 at 9:13 AM.

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    It has been said about Torres the during glue up he rubbed the back with alcohol (or something) a lit it on fire, it would burn for a few seconds, re-heating the hide glue so he could apply pressure and be sure of a solid glue joint. so.. heat bad? I dunnu, wood can also get pretty hot setting in the sun.

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    Back in the old days,when luthiers had no air conditioning to control humidity,they'd heat the soundboard in front of a fireplace to shrink it before gluing it down,avoiding cracks later on.

    If you noticed in my film about making the spinet,I heated the soundboard quite hot(without scorching) in front of the big fireplace. Then,it was glued down. I measured across the maximum width with a ruler before heating. After heating,the soundboard was at least 1/16" narrower than when cold. The soundboard was thus prevented from getting a severe crack in a future dry season. It has never cracked to this day.

    Heating tropical woods before gluing is a good idea. Ebony especially is a "cold" wood. Warming it,or rosewood,CAN help the glue. But,it also shrinks the top or back before gluing. Don't get carried away trying this. Spruce can suddenly shrink drastically in one place,and ruin a top.

    Torres was just using a variation of this process.

    For your info.,fly rod makers TEMPER their Tonkin cane bamboo in an oven at 350º F for 15 minutes before making fly rods out of it.
    Last edited by george wilson; 06-17-2014 at 10:29 AM.

  14. #14

    Cane rod builders

    Quote Originally Posted by george wilson View Post
    Back in the old days,when luthiers had no air conditioning to control humidity,they'd heat the soundboard in front of a fireplace to shrink it before gluing it down,avoiding cracks later on.

    If you noticed in my film about making the spinet,I heated the soundboard quite hot(without scorching) in front of the big fireplace. Then,it was glued down. I measured across the maximum width with a ruler before heating. After heating,the soundboard was at least 1/16" narrower than when cold. The soundboard was thus prevented from getting a severe crack in a future dry season. It has never cracked to this day.

    Heating tropical woods before gluing is a good idea. Ebony especially is a "cold" wood. Warming it,or rosewood,CAN help the glue. But,it also shrinks the top or back before gluing. Don't get carried away trying this. Spruce can suddenly shrink drastically in one place,and ruin a top.

    Torres was just using a variation of this process.

    For your info.,fly rod makers TEMPER their Tonkin cane bamboo in an oven at 350º F for 15 minutes before making fly rods out of it.
    \
    Easy there George! Cane rod builders formulas for heat treating Tonkin are myriad, infact cane rod builders are about the only craftsmen who are as supersticious as instrument builders! Having built both I can say that careful construction and quality materials trumps voodoo every time. Tempering cane is very effective, "my" recipes would have to be beaten out of me. Or searched for on the web where all can see...

    This is after all where I got them. Oh yeah and in books that I paid for.

  15. #15
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    Relative to the other 54,000 things that go into an instrument, I think this is a relative non-issue. It is an interesting question though.
    Shawn

    "no trees were harmed in the creation of this message, however some electrons were temporarily inconvenienced."

    "I resent having to use my brain to do your thinking"

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