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Hi all,

I have a couple of waney edge boards kiln dried and in my shed for a few years. Obviously not quarter sawn etc. What are the stability and strength considerations if I want to use it in guitar building. Thinking back (3 or 4 piece), sides, neck blacks or more likely vertical neck laminations with mahogany and possibly back of an archtop, possibly in a single piece?

Don't know if it makes a difference but this is cut in Ireland so I assume European cherry.

Secondhand conversation: A long while ago I posted a similar question in one of these fora, and the answers I got claimed that cherry is very stable, used for the bodies of countless carpenters' levels, and for good reason. I've made a few acoustic necks out of cherry, and save for it being as easy to shape as cast iron, it worked out well.

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Peter Havriluk

Thanks did you keep the grain vertical? Sounds great except for the cast iron part...

Cherry has high humidity expansion, similar to walnut, so use vertical grain if possible. It's not too brittle so it won't crack until it's gone significantly concave, but it will stress the glue joints in high humidity too.

I made one neck out of black cherry and had no trouble carving it. But I've made a lot of walnut necks too, so maybe I'm just used to it.

"Finding" tonewood is always a problem. Most of the wood in the world isn't tonewood. Off quarter wood can make guitar necks, but it looks weird on necks with a pegbox and scroll as part of the package. They are used to seeing it a certain way.

Off quarter seems to work better as carved backs, but I've seen LOTS of Rosewood backed guitars (in pictures, I never see real instruments!) that certainly aren't quartered. They are gorgeous though. If you have gorgeous wood go for it. Plane wood?

As far as carving? Cherry is pretty easy; like soft maple. Even the figured stuff is easy. The tools always need to be sharp. Even Wenge, that is pretty hard and heavy, is straightforward with sharp tools. Curly Birch is very hard, and the curl is VERY deep, so that can get you. Birdseye Maple that I'm carving now isn't bad, but the eyes can make things difficult, so you have to do them individually. Curly walnut and Padauk both cut fine, but Padauk, American Sycamore, and African Mohagany have that ribbon figure, so the grain switches all the time. Padauk is harder to see where it switches.

Plane, or take a cut off the ends of the boards and see what you have. If they are wide enough for a guitar, see if any can be centered on the body. Or maybe joined with other boards.

Finding wood is cool.

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Why be normal?

Wood with high shrinkage on drying can still be reasonably stable in use, so long as it doesn't see large swings in R.H.. What really matters with dry wood is the ratio of radial to tangential shrinkage; if that's low it won't warp or check much. Walnut is a fairly stable wood, with a R:T ratio of about 1.4. Cherry is higher; close to 2, so it has more tendency to cup and check if it's flat cut. I'd cut it narrow and flip every other piece to minimize cupping issues.

Alan, aren't the shrinkage ratios developed during the drying process from green to dry?

I think they are, and I'm not sure those numbers work for dried wood moving in an indoor environment while in use. Maybe they stay the same but I have doubts.

I've never seen a study on typical wood movement in the dry state, but wish there were data for that.

Warp and cup, etc is usually more pronounced in boards cut near the center of the tree that include both radial and tangential grain and the fight between them results in problems. Flat sawn boards cut further out from center of the tree move more across the grain but tend to stay much flatter. edit, I should have added quartersawn is always the best for stability. Truck John pointed out I forgot to include that. I love cherry and use a lot of it, though I haven't built a guitar from it yet.

In furniture we used to calculate 1% cross grain movement of quartersawn boards used indoors and 2% in flat sawn over RH extremes. They were just ball park numbers and slightly exaggerated but they worked and kept things together. I did some limited testing and my tests fell within those bounds.

American Black Cherry can be a problem. If the boards are straight and flat in storage I'd probably use them in an instrument. Take some measurements direct from outdoor storage, bring them indoors for a couple weeks and see if they've moved significantly. If so, I might find another use for them.

I'm pretty cautious with what I put in a guitar.

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Brian R, Wood Mechanic
N8ZED

While I won't claim the same level of experience with cherry as many here, I've used quartersawn stock for necks, backs, sides, a floating bridge, and various blocks. I've never had trouble with instability assuming it's properly dried and seasoned.

rbuddy wrote:
"Warp and cup, etc is usually more pronounced in boards cut near the center of the tree that include both radial and tangential grain and the fight between them results in problems."

I always look at the end grain: the more curvature there is to the annual ring lines on the end grain, the more trouble you'll have. Curved ring lines tend to flatten out as the wood dries.

I don't know if the shrinkage ratio is the same for dry wood as for green. I see no particular rreason why it should be differrent.

Note, though, that hemicellulose, the component of the wood that basorbs moisture from the air, breaks down over time. Old wood can't take up as much moisture, so it's more stable.

Most wood also has at least some built-in stress, and this seems to work it's way out over time and with moisture cycling. That's why they used to dry wood in drafty barns with good roofs: lots of changes in temperature and humidity helped work out the built-in stress. This has more to do with lengthwise warping than cupping across the grain.

The cherry hanging tool cabinet I made hasn't moved at all from what I can tell. More dovetails than I've ever cut for a single project! All the doors work as they should.

SS Stewart made almost all of their banjo necks out of Cherry in the 1890's. If they weren't subjected to abuse (read steel strings on a banjo designed for gut strings), they generally are straight and strong at over a hundred years old. I've seen great cherry guitars made by some forum members and some other very well known luthiers that have all been great. The ones I've seen were all vertical grain (same for the Stewart banjo necks). I wouldn't hesitate to use cherry. It's pretty, has a nice tone and seems to be very stable.

Dave

If I were making a back from non-vertical grain wood of any kind, I'd put a fairly substantial arch or dome in it. This would allow it to flatten with cross-grain movement without trying to go past flat, which is when cracks are formed.

I've made ukes this way with no cracking, though obviously those backs are much narrower so the risk is lower.

For necks I laminate two pieces with the grain opposing, like this: ////\\\\. That's nice and stable, and gives a good look to the neck. \\\\//// is equally stable (fingerboard on top), but doesn't look nice when carved.

I used cherry on a number of guitars
In my personal experience kiln dried was more stable than air dried
Sides should be .075 in thick
backs I think after glue up and take to .095

if your bending in a machine or hand bending ???
hand bending I have found that using a steam iron with the heat pipe allows for more efficient bending
on machine check out my bending library on you tune ( blue creek guitars ) Cherry works much like maple
so look for the maple video

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

This is really helpful everyone thankyou.

I've another slice at the back of the timber pile, anyone have a good link to making vertical laminate necks? I've cut out a load of pieces quite close to the finished neck size then glued them before, it is it much better to make a laminated version of a double neck blank and bandsaw the necks from the block?

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I did glue up a double neck blank from walnut once and then cut two necks out of it and it worked out just fine, I put a piece of maple veneer in the middle. The only reason I did it that way was because the wood I had was 4/4 x 8" so it was convenient to only do one glue-up. Obviously the wider the board the harder it is to get the mating surfaces true, I had a planer so that was not an issue.

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Steve Smith
"Music is what feelings sound like"

Doesn't look that promising...

It's been outside in an open shed in damp old Ireland so I doubt it's absorbed moisture very evenly after it's kiln drying 4 or 5 years ago. Do I leave it in the workshop and see does it settle? Cut it thinner? Throw in the firewood pile?

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For that application you need to glue the pieces up the other way, so that the grain in the outer laminates goes ))))|((((. The way you have it the distortion as it dries over time produces a peeling force at the edges, and most glues are not very resistant to peeling. Gluing it correctly pushes the edges inward.

Are those two outer lams book matched? Doing that helps even out the distortion: any tendency to curve off to one side in one piece is balanced by the other going the other way. The bottom picture looks right, but it can be hard to tell.

Turning them the other way also gives you medullary rays all the way around the neck. Quite attractive I think. I've done that on banjo necks for years.

Dave

If I were going to try to use it, I would weigh it (with a scale accurate to the gram) and move it to my humidity controlled room. I would check its weight every couple of weeks until it stayed stable for several weeks weighings. At that point I would judge whether I could plane and sand it straight enough to use and whether I wanted to. If I were gluing up a neck, I would want the opposing sides to be pretty symmetrical. A twisty neck is no fun.