Philosofy
437 posts
Dec 29, 2012
8:22 PM
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What is the preferred grain direction on wood harmonica combs? From my woodworking, I know that end grain absorbs moisture easily. If the end grain runs left to right, then there is a lot of end grain exposed in the slots: not good. If it runs front to back, then your tongue hits in on the front of the harp, and might not be comfortable. End grain running top to bottom would have the grain sealed off from moisture by the reed plates, but the comb might cup.
What do the experts say about this?
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ElkRiverHarmonicas
1455 posts
Dec 29, 2012
10:15 PM
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Grain runs from end to end. It has nothing to do with moisture. been like that since Day 1 of harmonicas. Pearwood doesn't have a real noticeable grain, but not all makers back then were using it. The Klingenthal makers were using beech, which has a more perceptible grain.
The reason the grain runs like it does from end to end is because of the bottom of the 1 hole. That is a very, very thin piece of wood. If the grain ran any other way, the comb would be extremely weak - and it already is pretty weak - at that one point. There's a lot of leverage there. Factory workers would be breaking them left and right before they got the harps built.
The trade off is that the comb teeth are weaker than they would be otherwise.
Oh, and the grain wouldn't have been a problem on the comb teeth for comfort. The comb blanks were smoothed around the edges before the comb was cut out.
You might be interested to know this... since the 1800s, they've used gang saws to cut wood diatonic combs. I don't know if they are still used on the Marine Band.
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David
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At the time of his birth, it was widely accepted that no one man could play that much music so well or raise that much hell. He proved them all wrong.
R.I.P. H. Cecil Payne
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David
Elk River Harmonicas
 
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Philosofy
785 posts
Dec 06, 2016
8:01 AM
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I'm bumping this old thread to see if there are any other opinions on the subject. Not that I don't trust Dave, but wanted to see what Andrew or Tom have to say on the subject.
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JustFuya
1005 posts
Dec 06, 2016
12:14 PM
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When I looked at the photo of jpmcbride's split comb in his recent thread, the first thing that struck me was the grain direction. It cracked exactly as I would have expected. (Although it was misfortune to blame rather than design.)
I don't have the woodworking experience (yet) to say one direction is better than the other but my gut says David is correct.
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Raven
84 posts
Dec 06, 2016
12:56 PM
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In woodworking, end grain will always absorb more of any liquid, especially stains. Therefore it will appear darker if not treated first with end grain sealer. This is standard in the furniture industry before a piece goes through staining. Proper sealing is the answer to any wood being used in an environment that could induce moisture.
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dchurch
75 posts
Dec 08, 2016
8:27 PM
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Expert? Anyway, as David pointed out wood grain runs end to end, at least on every MB… that I’ve seen.
Yes, end grain is more apt to draw and release moisture. That’s why the ends of raw lumber are sealed to prevent checking… (as per Raven) It also accounts for why tines expand beyond the plates. Lumber/grain is much more stable in length rather than width. That’s why decks… are built with a gap between boards, to allow for this expansion.
Species is a major factor in stability and grain characteristics. Pear wood, apple, balsa, box wood… are very fine grained. Rosewood is very stable. It is, or was the wood of choice for levels and measuring devices… You can split a piece of Red oak (not white oak) into a 1” x 1” stick 6 feet long, put one end in a bucket of water and blow bubbles using the other end like a soda straw.
Another factor is how the lumber is sawn relative to the growth rings: plain sawn, rift sawn or quarter sawn. Quarter sawn being the most stable.
That said there is no reason a comb could not be made with other grain directions. Running the comb grain lengthwise makes for weak tines. But if you run it front to back the comb is more susceptible to warping along its length...
Again a lot would be determined by the wood species and to a lesser extent how fast the tree grew. A slow growing tree produces smaller tighter rings.
I’m guessing you are interested in making a wood comb.
It may be beyond your plan but you could consider laminating three thin pieces of wood, running perpendicular grain. That would produce a much stronger and more stable piece to work with. In fact I’m surprise that hasn’t been commonly used at some point (not counting impregnated laminates).
Best of luck,
Dave
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It's about time I got around to this.
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