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I did not expect to be doing any resawing any time soon. I had only thought about buying wood already cut. But I have happened upon some mahogany lumber that I want to latch on to for the future. So this is a basic question. What are the minimum dimensions to make sure and have for:

1. Martin Dread size guitar Back, Sides and Top?

2. Martin OM size guitar Back, Sides and Top?

3. OLF SJ size guitar Back, Sides and Top?

Thanks in advance for the basic help.

Any other tips for selecting wood in the large lumber state would be appreciated. I assume selecting all quartersawn would be best. Or can flatsawn also work for necks after resawing?

Ed

I could get the dimensions from my OM build if I remember to check tomorrow when I'm in the shop. Yes, you can use flatsawn for the neck but the 1/4 would be much better structurally to counter the string tension. You could always flatsaw thinner pieces with the idea of building a laminated neck which looks better imo. Then it'd end up with vertical grain anyways.

Minimum dimensions, if you're talking about slices, can vary widely based on how well you saw the board and the quality of the cut itself. A good resaw setup with a good operator can get six clean slices to an inch. A poor resaw will get four. The difference is both in how straight the cuts are and how much cleanup is required on the pieces post-cut.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Hi Ed,

Here are the minimum sizes I look for (I put in a few other guitar shapes in case it helps anyone else):

D top/back = 19.75" x 15.25" (two pieces 19.75" x 7.125")
D sides = 30.5" x 5"

OM top/back = 19.5" x 15" (two pieces 19.5" x 7.5")
OM sides = 30.5" x 4.25"
OMC sides = one 31.5" x 4.25" and one 30.5" x 4.25"

SJ top/back = 20" x 15" (two pieces 20" x 7.5")
SJ sides = 30" x 4.5"

MJ top/back = 20" x 16.5" (two pieces 20" x 8.25")
MJ sides = 31" x 4.75"

Classical (Hauser) top/back = 19" x 14.5" (two pieces 19" x 7.25")
Classical (Hauser) sides = 28" x 3.75"

I always try to find wood that exceeds these dimensions to take account for edge damage, jointing, end splits etc. For the backs/tops I like to see about 1" extra all around. So for an SJ top I really want to see two pieces 21" x 8". For the sides, I like to see a couple extra inches on the length and at least an extra half inch on the width, so for SJ sides I really want to see two pieces 32" x 5" minimum.

When I resaw my own from billets, I like to slice pieces off about 1/8" thick or just a little larger. Like Bob says, it all depends on how good your resaw set up is - if it's not too smooth, you may want to cut slices as thick as 0.175" and then sand them down to size. Hope this helps!

Cheers,
Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

I do believe that this is true depending on the blade you use. A thin kerf blade .020 will produce more than a blade say with .051 kerf. But watch out for the 4/4 lumber this could be less than 1 full inch.

Not to boot but your re-saw skill need to but up to snuff.

The math isnt hard.

Hi, I own a cabinet and furniture shop and am building my first guitar. Our shop does resawing every couple of days. Be extremely careful resawing with thin kerf blades. The most common cause inaccurate resaws is blade wander because the blade gets hot and expands, then finds the path of least resistance in the stock and results in varying thicknesses. My smallest resaw blade is a 3 hook / inch that leaves a 1/16 cut. Set up tall featherboards or puchase a resaw feeder if you plan to do this often. Try to obtain lumber that is 8/4, 10/4 or 12/4, if you know what you want put "want to buy" listing on woodplanet.com. T

The answer to your question (in the original post) with a short and sweet doesn't really cover all the bases....sooooooo...

If you are resawing for YOURSELF...you need to consider your skill level and technique in jointing the boards together. For example: If you have little experience jointing boards and have trouble getting the boards to line up correctly, you'd want a yield off the saw of somewhere in the .160's plus (thous I mean). This way when you run the boards through your thickness sander you can stop at about .140 and then glue your boards up. That's not to say you can't glue up right off the saw, but I like the boards a little cleaner for glueup...just me. This leaves plenty of room for you to fudge a little and still get accurate cleanup on the sander AFTER the boards have come out of the clamps. If you've got good jointing chops shoot for the .120's off the saw (this assumes the saw is equipped properly and set up properly), then glue, then cleanup.

Proper saw setup:
Resawing demands more of every component of the saw. They all have to work together 'better' than your standard run of the mill setup for cutting spindles for chairs and stairs. Bob Garrish mentioned above getting 6 slices out of a board. If your setup is good and your technique is good (yes there's technique here) then yes...you can get each board to yield at .120 or less off the saw for each slice. On a board that is truly 1 inch thick...6 slices that are .120 is .720 thou total. That leaves .280 thou for the kerf of the blade to use during the entire operation. Six slices, or more specifically 6 boards off the billet means 5 cuts. That remaining .280 thou is reserved for those 5 cuts and in this scenario each of those 5 cuts CAN'T be more than .056 thou wide (width of the final kerf of the blade). .280 / 5 = .056. Keep the frame of reference here okay.....this is a mathematical scenario....but in this scenario there is not a single thousandth's of an inch you can spare anywhere. So what do you do to get 6 boards...you don't make a single mistake. Can it be done? Most absolutely. You have to be careful here though...remember you still have to join the boards and after cleanup on the drum sander, a .120 thick piece might end up at .110. NOTHING wrong with that. The last guitar I finished had a Cocobolo back and side set that I joined at .088 and it was a bear. I looked like Felix the Cat when it was done. I much prefer jointing in the .130's but that's just me.

Bob if you read this please don't take it as a treatise against your claim. I view it as support but with greater specificity. I just thought there were other factors that might come into play for the original poster.

GW20 mentioned a .020 blade, speaking in reference to kerf I think. Spectrum Supply sells a blade that has an .016 band and I forget what the actual kerf is but obviously it's really thin. I used one of these once to slice up a Spruce billet that was 2.5 inches thick. By the end of the job on that billet the blade was gone. The thinner blades aren't going to last as long as thicker blades. As a rule in resaw, the fewer teeth the better. Big fat deep gullets under the teeth is what you want. If the blade can't clear the chip as it passes through 8 inches of wood you'll run into problems. Alternate tooth counts are your friend.

Dimensions:
When I first started resawing lumber for guitars I went through this too. Now I consider a single group of dimensions before I buy a board, rather than, 'that'll make OM's or L-OO's'. I always shoot for the following sizes: 21 x 8 for backs and 35 x 5 for sides. Why? Because your mind will change a thousand times regarding whether or not you want to use that piece of Mahogany for a Dread or that really sweet OM...or a Gibson L-OO copy. AND, if you decide to sell it to fund a tool purchase or something, those dimensions cover the gambit of your potential client base. Cut your billets for OM's and you can only sell them to people that are building OM's or smaller. Does that mean I pass up lumber that will yield smaller sizes? No...but in this case it needs to be a special board. Keep in mind...just my opinion. If you don't think you'll be selling any of it, which I did too, then do your thing your way. No wrong way here.

Dave mentioned finding lumber that is dimensionally larger to account for defects and he's dead on. This brings me to the Garbage in Garbage out rule. If you feed your saw garbage, you will get garbage out the other end. Make sure there's room on the billet for cleaning and squaring PRIOR to running it through the saw. Don't run a side billet through that is bowed. Each cut will exacerbate the bow and while you may still get a few pieces to use....the board won't yield what it's supposed to yield. This stuff is way too expensive to be throwing away.

Chris

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There is no difference between the man that thinks he can....and the man that thinks he cannot.

Thanks to everyone for the quick answers. This was exactly what I was looking for on the dimensions. The tips for resawing are also very helpful as I am 100% green here. More tips would be appreciated as well. I did not expect to be doing any resawing as I said. But I have hit upon a deal that is too good to pass up.

Please keep the actual sawing tips coming. I may just go to someone else to do it, but it would be fun to try a small amount. Unfortunately, I have only a 14" Delta bandsaw that is only 3/4 HP. I have seen a tip about using the table saw to start the cuts on each side to help control the blade/cut in this situation. Even though it hurts the yield, that might be an option for me with this undersized/underpowered bandsaw which I did not expect to be using for this.

Please keep the selecting lumber tips coming.
Thanks again.
Ed

Here's more stuff:

viewtopic.php?f=10101&t=26906&hilit=resaw

And another...
viewtopic.php?f=10101&t=25672&hilit=resaw

And another....
viewtopic.php?f=10101&t=22328&hilit=resaw

This is a good one too...
viewtopic.php?f=10101&t=25760&hilit=resawing

_________________
There is no difference between the man that thinks he can....and the man that thinks he cannot.