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Hi

Given the great response on my first question on this forum I try another.

I am building an acoustic guitar as described in a book by Jonathan Kinkead. The book is great, but there are one or two things I don't understand. One of them is the grain direction of the top and bottom blocks. The book says: ""Make sure that the grain of each block runs in the same direction as that of the sides, so that the neck, sides and blocks move in unison during changes in humidity". Ok, but the way I see it the sides and neck grain have different directions at the neck-body joint. The logical thing for me is to make bocks with grain that is equal to that of the neck, so that the dovetail joint stays tight.

Am I missing something, if so can someone give me their best advice on grain directions of the top and bottom blocks?

A note; neck, sides, back and blocks are all mahogany. Though I have to glue the bocks together if the grain dirrection is to match the neck.

Old school...

I make mine out of Baltic birch plywood...

Personal thought here. If the grains of two differnt woods with two differnt expansionrates are running in the same direction then you have one pieces of wood want to expand in the same direction but at a diffent rate as the other. While it is good that they are both expanding in the same direction. I an not so sure it is all that benificial. I have always been (right or wrong) of the mind that you get a more stable joint by countering the grain. When you buy a neck block or tail block from Stewmac and or LMI the grain of th Mahogany they are maid from is running vertical ie. end grain to the top and bottom of the guitar.

Like Rick when I make my own block. Now that I no longer have John Watkins necks available(at least for some time to come) I use birch play to make my blocks

Once again, you can over-intellectualize this stuff 'til you're just nuts. In reality, if you're using decently quartered and dried wood for sides, then you'll not get enough expansion and contraction to need to run the grain of the blocks parallel.   If that were really so important, you wouldn't have ladder braced backs on guitars, nor would you have side braces as many of us put in.

One of the main reasons why many guitar makers ran the grain parallel to the grain in the sides was for ease of trimming by hand with a block plane. The problem is that a good hit on the end strap button, and you've got a crack that can go all the way around the guitar.

Baltic birch meets all the needs I can think of for excellent end blocks.

Another end block trick is to bevel it back so the top glue surface is the width of your lining (am I allowed to say "kerfing"...a perfectly good new word?).

The only problem with birch ply is that it does not move at all. So the stability benifits are not there. The sides will still move more than the neck block, although it will likely be minimal! For mine I run the neck and tail blocks with the grain oriented the same as the sides. One reason I do this is so that I am not gluing the top and back onto the endgrain of the neck and tail and block. With modern glues this may not be as big of an issue but one of the first premises of woodworking is avoid gluing to end grain and I stick to that premise when ever I have the opportunity (going on 30 years now!). Having said all of this, edge grain mahogany sides are likely to move very little, especially once they have been 'cooked' during the side bending process. And the baltic birch blocks will be stronger with less chance of ever splitting.

Hope this helps.

Shane

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Canada

You can say it, but don't tell Howard.   

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I glue cross grain on the tail block to avoid a split from a sharp bump. Then to avoid gluing top and bottom to end grain I glue-joint a cross grain piece to the top and bottom of the block. Read this somehwere, maybe Courtnall, not for sure.

Birch ply will move just enough, and once again I'd like to point out that there's a lot more "movement" across 16" of back width than across a cooked set of sides at a quarter of that width. In fact, there should be four times as much movement across the back.   So why do we glue braces across the grain of the back? Because it simply works. There's a point where we have to get out of our heads and look at the real world, and in the real world we do lots of "no-no's" building guitars. And said no-no's often work just fine for the job at hand.   

Having repaired a few too many guitars with cracked end blocks, I've gone to Baltic birch. I can't see a hint of a problem with the guitar that I made that went to Antarctica, so I think the rest will be just fine... Ditto with Jeff Traugott's multi-mega-thousand buck guitars...Baltic birch end blocks. No problem now and highly unlikely that there will be issues in the future.

I also use baltic birch ply, but with mahogany caps like Marc shows, so that you're not gluing the endgrain of the baltic birch to the top or back. Even if I use mahogany for the block, I'll cap it so that thee's no gluing to end grain. I can't say if it makes any difference at all to do glue it on the baltic birch, but my intuition says "yes". The baltic birch does provide fantastic strength and split resistance, especially if you're using an end-pin jack.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I have got to learn to keep my opinions to myself!  

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I have a cypress Marcelino Barbero flamenco from the 60's. This is a Japanese made guitar that Sherry Brenner used to have made for their own lable. It is a really nice guitar but the block was glued in with the grain vertical. The block did not shrink as much as the rest of the guitar, and the fingerboard got a hump in it over the block. I had to have a refret done, with planing of the raised area. It has been OK now for more thatn 30 years.

I have one of the Classical versions of the Marcelino Barbero, and had to do a refret job on it because the fret ends all were popping, and because of the undercut, couldn't be reset.  While I was at it, I sloped the fingerboard to the bass side, and improved the action immensely.  The guitar is a boomer, and a cannon, but I don't use it much because I really like a spruce top much better, and I also like the 650mm scale vs the 660 on the Barbero.  It is a very lightly built guitar.  I have not noticed any problems with a hump in the fingerboard from variations in shrinkage.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Only half or so of the Baltic birch is endgrain, and from my experience in building speaker cabinets out of the stuff, even the end grain glues better than you'd expect from theory, and once again, we can think these things in circles and in the end it doesn't matter a bit other than the fact that what works simply works.

So.... I'm wondering what would happen to a baltic birch neck block if the neck dovetail joint cut into it had to be steamed to remove a neck.  Is the glue that it is made with waterproof and heat proof??

Mark

Mark's question is the reason I make my own laminated blocks, even though there will never be a reason to steam mine. I just don't trust a plywood plant's glue or glue joints. Not as long as I'm to honor the warranty(gee, I'm sounding like Rick <g>)

I live but 25 miles from a hardwood plywood plant, that has, on occasion, cranked out birch ply, but mostly makes the various veneer-covered plywood that cabinets and furniture are made from. Their glue begins life as flour.... sacks of flour. Robin Hood flour, last time I visited....

The Baltic birch is marine grade...no voids, all birch, not just the faces...9 ply for the 1/2" stuff, 13 ply for the 3/4" stuff. It is eminently trustworthy stuff.

Since I don't dovetail necks, "it don't make no never mind to me" regarding steaming for a reset. It might be interesting to toss a chunk in a pot of boiling water to just see what it would do.   Mark, should I send you a chunk to try?

Kinkeads book has a few issues, neck angle, and shellacking the top before you do the braces are a couple others. Ive read reviews of his guitars and people seem to really love them. Shellacing the interior is also another issue, although he lives in Britain, so that may be why?

Different strokes for different folks...
Best thing would be to ask him. I don't think we can answer for him, but a number of Spanish luthiers shellac the interior, and I've done some.   Looks nice... May slow humidity changes, but not prevent them... May brighten up the sound a bit...

I have the kinkade book and its a very good book. But a lot of the things he does are in the old style. There are new methods out there. So don't take what he does as bible. Thats just the way he does. There are a lot of other good books like Cumpianos and Slones books. Both are old but i think your learn more reading Cumpianos book then Kinkades. He gets a little more into theory of building.

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Guitars, guitars and more guitars.

Rick

I don't dovetail my necks either, but for those who do it might be an issue.

No need to send me a piece to boil... I like using mahogany for neck blocks and intend to continue doing so.

I do like the idea of baltic ply for tail blocks, though. It seems like it would work great for that. Maybe I'll switch from mahogany some day.

Mark

One of the advantages of Baltic birch for neck blocks is that it is more crush resistant than mahogany and it's less likely to swell with high humidity and then shrink back down when it dries which can loosen neck bolts.   When I was doing straight butt joint bolt-ons I used Belleville washers between the Allen bolt head and a flat washer to help take up any slop. They're basically springs with lock washer teeth as well. McMaster-Carr...

I've use mahogany for neck blocks and BBply for the tail blocks in the (two )
acoustics that I have built. I am interested in the BB ply neck block though.
Rick would ye mind posting a pic of one of your neck block so that we may
see the way it is put together if it not too much trouble. Thanks   k

Here's an interior shot showing lots of what we do...not everything, but quite a bit...

Rick,

That's really neat. I'll have to have a go with the cf capped backstrip sometime soon. Presumably you have to have the back in it's final lengthwise arch before you glue on the cf strip? And then put on the back braces with notches to bridge the back strip? I don't build in a sanded dish (as I don't do spherical surfaces) so would have to work out how to handle this.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010