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Is using slab-sawn wood for violin ribs just plain wrong?


MusicShop Pete
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Hello all, I'm a self-learning newbie making my 1st violin and I have a question about the woodgrain orientation of the ribs. I bought a really nice piece of slab-cut quilted maple for a single piece violin back plate and I saw in violin-making books that the matching ribs are made from quarter-sawn wood. I don't have access to a quarter-sawn piece of the same tree from which to get the ribs. I'm a bit at a loss as to how to proceed since I am sure there are good reasons for the recommendation having to do with strength, shrinkage over time, resonance/tone, etc.

My only way out it seems, short of finding new wood, would be to make strips off my quilted maple slab to make the ribs. But then the grain is out of whack. What would the downside(s) be of doing this? If feasible, looking at the end grain which is horizontal, should I make the ribs on this horizontal plane of the slab or on the vertical plane? Is using the slab for the ribs entirely out of the question?

I thank you in advance for any help.

MusicShop Pete

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Welcome to MN!

Imo it's your first instrument so don't get too stressed just build it and go on from there. Having that said, with a quilted back you could easily just use a non figured but quartered or quartered figured maple. The quartered material will be easier to bend, non figured even more so. I wouldn't use plain sawn for the ribs. You can get a rib stock from several suppliers so that probably makes the most sense. 

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Thank you all for your input ... much appreciated. I went back to the wood supplier and couldn't find anything I could use. So I think I'll take the middle road. As Mike S. suggested, since this is my 1st violin, I won't stress too much about not having quarter-sawn ribs for my 1st violin. At this stage, it's all about me learning. But I will heed the advice given to me by all and get quarter-sawn rib wood for my next violins.

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14 hours ago, MusicShop Pete said:

Hello all, I'm a self-learning newbie making my 1st violin and I have a question about the woodgrain orientation of the ribs. I bought a really nice piece of slab-cut quilted maple for a single piece violin back plate and I saw in violin-making books that the matching ribs are made from quarter-sawn wood. I don't have access to a quarter-sawn piece of the same tree from which to get the ribs. I'm a bit at a loss as to how to proceed since I am sure there are good reasons for the recommendation having to do with strength, shrinkage over time, resonance/tone, etc.

My only way out it seems, short of finding new wood, would be to make strips off my quilted maple slab to make the ribs. But then the grain is out of whack. What would the downside(s) be of doing this? If feasible, looking at the end grain which is horizontal, should I make the ribs on this horizontal plane of the slab or on the vertical plane? Is using the slab for the ribs entirely out of the question?

I thank you in advance for any help.

MusicShop Pete

Hi,

If you're planning to make your ribs from the same wood as your back make sure it is well seasoned and should give it at least 6 months to season in a dry place.

As Jacob says in his post, slab cut ribs tend to split, especially near corners,top and bottom blocks. But they need a few handred years to do it if the ribs were well seasoned before bending. On the plus side, slabcut wood is a lot easier to bend. You may have to leave the ribs a bit thicker as slab cut ribs have a bit less resistance to downward pressure of chinrests and clamping.

There are some slab cut ribs from more than three hundred years ago.

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4 hours ago, Wolfjk said:

Hi,

If you're planning to make your ribs from the same wood as your back make sure it is well seasoned and should give it at least 6 months to season in a dry place.

As Jacob says in his post, slab cut ribs tend to split, especially near corners,top and bottom blocks. But they need a few handred years to do it if the ribs were well seasoned before bending. On the plus side, slabcut wood is a lot easier to bend. You may have to leave the ribs a bit thicker as slab cut ribs have a bit less resistance to downward pressure of chinrests and clamping.

There are some slab cut ribs from more than three hundred years ago.

Thanks for the tip about the thickness and time to season the wood. I've had it air drying in our house for over a year now. Don't know about its history although it seemed light enough when I bought it.

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7 hours ago, MusicShop Pete said:

Hi Michael, good advice...how long are you waiting for your maple to dry before using it?

First of all, I buy wood that had been cut for several years. Next, I store it in my shop for two or more years before I get around to using it. I have some maple for over 10 years. Many makers stock up with wood over time.

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9 hours ago, Wolfjk said:

As Jacob says in his post, slab cut ribs tend to split, especially near corners,top and bottom blocks. But they need a few handred years to do it if the ribs were well seasoned before bending.

It's not about hundreds of years. It's cycling humidity extremes that cause the cracking. This could happen in a week. For a given change in moisture content, slab cut wood changes dimensionally twice as much as quarter cut wood. That makes it much more susceptible to cracking.

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7 hours ago, clearsky said:

It's not about hundreds of years. It's cycling humidity extremes that cause the cracking. This could happen in a week. For a given change in moisture content, slab cut wood changes dimensionally twice as much as quarter cut wood. That makes it much more susceptible to cracking.

Hands on experience indicates that once the wood is well  seaoned (not just dried but exposed to the natural temperature and humidity changes of the seasons) the difference of expansion and contraction is less than at the start of seasoning.

The reason the ribs are more likely to split on the blocks is the orientation of grain; up and across. The contraction/expansion lengthwise is afraction of across the grain.

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8 hours ago, clearsky said:

It's not about hundreds of years. It's cycling humidity extremes that cause the cracking. This could happen in a week. For a given change in moisture content, slab cut wood changes dimensionally twice as much as quarter cut wood. That makes it much more susceptible to cracking.

Agreed. On quarter cut ribs, the highest percentage of dimensional change, due to humidity variations, will be to the thickness, which a violin can accommodate quite well. With slab ribs, the greatest deviation will be to the height, which the blocks (which hardly change in height at all) won't allow. Humidity goes down, ribs contract in height, blocks don't, and you get spits in the ribs, usually starting near the blocks.

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3 hours ago, David Burgess said:

Agreed. On quarter cut ribs, the highest percentage of dimensional change, due to humidity variations, will be to the thickness, which a violin can accommodate quite well. With slab ribs, the greatest deviation will be to the height, which the blocks (which hardly change in height at all) won't allow. Humidity goes down, ribs contract in height, blocks don't, and you get spits in the ribs, usually starting near the blocks.

 

Can a scroll be made from a flat sawn block? Or will it twist with humidity changes?

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The reason that slab ribs tend to crack, is that they are pre-destined to shrink in the height, whereas the blocks that they are glued to do not. This causes a tension which results in a crack (some cracks) starting from around the block area, which are almost inevitable. I, for one, would not use slab ribs for this reason, and would advise the OP not too, unless he has nothing else, or is not bothered. The scroll by contrast, isn't really glued to anything much that might encourage it to crack anywhere, as far as I have noticed, and I'm sure you could make it from anything you liked.

,

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On 9/2/2017 at 6:18 AM, MusicShop Pete said:

Hello all, I'm a self-learning newbie making my 1st violin and I have a question about the woodgrain orientation of the ribs. I bought a really nice piece of slab-cut quilted maple for a single piece violin back plate and I saw in violin-making books that the matching ribs are made from quarter-sawn wood. I don't have access to a quarter-sawn piece of the same tree from which to get the ribs. I'm a bit at a loss as to how to proceed since I am sure there are good reasons for the recommendation having to do with strength, shrinkage over time, resonance/tone, etc.

My only way out it seems, short of finding new wood, would be to make strips off my quilted maple slab to make the ribs. But then the grain is out of whack. What would the downside(s) be of doing this? If feasible, looking at the end grain which is horizontal, should I make the ribs on this horizontal plane of the slab or on the vertical plane? Is using the slab for the ribs entirely out of the question?

I thank you in advance for any help.

MusicShop Pete

I had a Santo Serafino violin in the shop not too long ago where it was necessary to remove the top. The slab cut bird's-eye maple ribs were thickest in the lower bout, especially near the endpin area, approaching 2.0 mm. The rest was variable but all on the thick side from 1.3 to 1.7 mm. The thinnest area found was the c-bouts at about 1.1 mm. The only cracks in the ribs were from seasoning shrinkage at the block areas; especially the ends of the ribs at the corner blocks.

Bruce

 

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12 hours ago, Michael_Molnar said:

First of all, I buy wood that had been cut for several years. Next, I store it in my shop for two or more years before I get around to using it. I have some maple for over 10 years. Many makers stock up with wood over time.

Wow, that's a long time! Must take discipline to have a beautiful piece and have to wait. I can see how having an inventory will be important to keep me from raiding stock that has not been seasoned long enough. Even though this is a retirement  hobby for me. I do want to make beautiful and good-sounding instruments to the best of my abilities. I'll need to find a good source of wood that has done a lot of the seasoning in advance so I can get started and grow my inventory over time. At 63, time is of the essence!

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54 minutes ago, Michael_Molnar said:

Can a scroll be made from a flat sawn block? Or will it twist with humidity changes?

Mike, Based on the diagram below, Quarter sawn would have the least twist regardless of the grain orientation.  A quarter turn of the neck block should only have a visual effect.  I'm assuming you're not talking about having the end grain on the fingerboard and neck/hand contact surface.

-Jim

shrinkage.jpg.6135df7db37adf366ae051f8457f95c7.jpg

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1 hour ago, Michael_Molnar said:

Can a scroll be made from a flat sawn block? Or will it twist with humidity changes?

Not so much twist as I have seen a lot of split pegboxes as the maple splits easier if the pegbox is slab (flat sawn). The pegbox wall should be made much thicker and obviously well fitting pegs help too.

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You know, in the world of guitar building, at least in my knowledge, grain orientation isn't often considered. I have several guitars each with necks in all kinds of crazy grain orientations, including tons of  runout, that haven't moved even the tiniest bit from humidity over the course of fifteen years. Some of my older examples include a nylon string acoustic from early 1900 that has an off quarter neck, which has stayed rock solid for over a hundred years. 

I don't know if it's the same for violins or not, though.

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1 hour ago, MusicShop Pete said:

Wow, that's a long time! Must take discipline to have a beautiful piece and have to wait. I can see how having an inventory will be important to keep me from raiding stock that has not been seasoned long enough. Even though this is a retirement  hobby for me. I do want to make beautiful and good-sounding instruments to the best of my abilities. I'll need to find a good source of wood that has done a lot of the seasoning in advance so I can get started and grow my inventory over time. At 63, time is of the essence!

 

Like many other makers, I buy nice pieces and squirrel them away. I date them along with the source. The trick is to have lots of nice pieces so the latest addition does not tempt you.

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2 hours ago, Michael_Molnar said:

Can a scroll be made from a flat sawn block? Or will it twist with humidity changes?

 

2 hours ago, jacobsaunders said:

 The scroll by contrast, isn't really glued to anything much that might encourage it to crack anywhere, as far as I have noticed, and I'm sure you could make it from anything you liked.

,

 

1 hour ago, Bruce Carlson said:

Not so much twist as I have seen a lot of split pegboxes as the maple splits easier if the pegbox is slab (flat sawn). The pegbox wall should be made much thicker and obviously well fitting pegs help too.

In addition to the concern about the pegbox cracking, there is an issue with the heel glued to the endblock.  There is bending stress here (cracking concern) as well as differential expansion relative to the upper block, which may make seasonal neck projection variations more pronounced.

For neck twist, I think an off-angle cut would be the worst case, or grain that has some twist to it.

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