quarter sawn vs rift sawn european white oak

[Dominique Meuris]

Dear

We have a furniture factory in Romania.
But at this moment we are currently buying all of our oak with full truck loads of quartersawn oak A-quality. Dried to 6%-7% humidity.

But we are thinking of sawing our own logs in a few years. For this we would buy fresh cut oak logs in the Ukraine or Croatia.
They must be cut around february "because there is less sapwood then". and minimum diameter 50cm.

But does anyone know how much waste you have in general when cutting quartersawn oak. only a-quality
and when cutting rift sawn oak. only a-quality

And if someone has an idea of how long it takes to cut this aswell. m³-wise.

If we are going to do this, we would be buying around 500 m³ of logs every year. But we would need atleast 125m³ of A-quality wood out of this "rift sawn" and ofcourse around 100m³ of b-grade wood. "for making the backs & shelves" All the waste will be used for heating the factory.
Is this even possible?

And after sawing we would stack it up with stickers "the complete boards", and then let it dry for around 6 months in the air. Then we would saw it in smaller boards and let it dry again for around 4 months. again air drying. Ofcourse all of this will be covered from the rain ...
And then KD

Already thank you!!

[Phil Thien]

The (English) technical term you need to google is "green lumber grade yields." These will vary by species, as well as size of the tree.

Here is a link which covers yields in general:
http://www.fs.fed.us/ne/newtown_squa...ned/rp468a.pdf

Here is a link where they talk about quarter-sawing lumber, and mention some yield issues:
http://trace.tennessee.edu/cgi/viewc...=utk_agexfores

Good luck!

[David Hawkins]

A lot will depend on the experience of your log buyer and your sawyers as to what yield you will get. If they know their business they should be able to give you good estimates considering your local conditions. If they can't give you this information you need to get new people with more experience.

As to the "sapwood" being less in February I have never heard of such a thing (I was a kiln operator for years and have dried millions of board feet of oak. There may be less sap in the wood in the winter but the sapwood itself just moves out in the log and turns to heartwood over a course of years.

For Furniture grad oak you are really going to have to re-think your drying plan. To get 6% to 7% moisture content (which is different than humidity) then you will need to use dry kilns, there is no economical other way. My experience has been with steam operated kilns and we had 16 dry kilns that held 40,000 to 60,000 board feet each (depending on the thickness of the wood) Oak took an average of 40 days from green to 5% mc. Air drying it first produced too much degrade. Oak is very prone to degrade under uncontrolled conditions. I think you will find that the cost of kiln drying from green will result in very profitable increases in the final yield.

Hope this helps

[Dominique Meuris]

A lot will depend on the experience of your log buyer and your sawyers as to what yield you will get. If they know their business they should be able to give you good estimates considering your local conditions. If they can't give you this information you need to get new people with more experience.

As to the "sapwood" being less in February I have never heard of such a thing (I was a kiln operator for years and have dried millions of board feet of oak. There may be less sap in the wood in the winter but the sapwood itself just moves out in the log and turns to heartwood over a course of years.

For Furniture grad oak you are really going to have to re-think your drying plan. To get 6% to 7% moisture content (which is different than humidity) then you will need to use dry kilns, there is no economical other way. My experience has been with steam operated kilns and we had 16 dry kilns that held 40,000 to 60,000 board feet each (depending on the thickness of the wood) Oak took an average of 40 days from green to 5% mc. Air drying it first produced too much degrade. Oak is very prone to degrade under uncontrolled conditions. I think you will find that the cost of kiln drying from green will result in very profitable increases in the final yield.

Hope this helps

So you would just put the wood in the kiln just after cutting it?
Because I have spoke to many people before regarding this. And a lot of people think that this is to aggresive. That it should be air dried for a while, before putting in a kiln.
But I don't have any experience with this, so just trying to find out the best way.

What do you mean with the degrade? I'm sorry but my English isn't really in the best shape.
Being a Belgian it's only my 3th language ...

anyway, already thank you for the help

[Charlie MacGregor]

Degrade can be described as warp, cup, bow, split, case hardening, mold, stain, or fungus. Proper kiln drying is about environmentally controlling the rate of moisture removal. There are schedules for species and dimension designed to minimize degrade while drying efficiently. It is the lack of control in air drying that can contribute to defects.
Regards

[David Hawkins]

This is an "It depends" situation. Some woods need to be in the kiln the same day it is sawn, Pine and Oak are two of these. Pine to avoid blue stain and Oak to prevent checking and collapse. Other woods such as Birch, Cherry, Maple and Cedar can be safely air dried to about 20% mc before going into the kiln. On average we had over 600,000 board feet in our kilns at any point in time, average time in the kiln was an average of 18 days (including air dried), Oak would run about 40 days from dead green, aird dried would take 10 to 15 days depending on the various factors. So figure 10 million feet a year.

Wood that went into the kiln dead green always gave a higher yield than wood that was air dried. The only reason that we air dried at all was to increase volume to meet production demands, with just 16 kilns we had to be able to push the average run times down as much as possible.

[Dominique Meuris]

Hi David

thank you for all the usefull information so far. It's alway's betther to hear from someone who has experience with the matther.
At this moment we are still buying from our current sawmill. both Quartersawn & dosse sawn wood.

But we prefere the look of quartersawn, but we don't like the flakes in the wood. So I was thinking of rift sawing. But nobody can really give me a good explantion of this. Is it even possible to have the structure of quartersawn but without the flakes?

This is an "It depends" situation. Some woods need to be in the kiln the same day it is sawn, Pine and Oak are two of these. Pine to avoid blue stain and Oak to prevent checking and collapse. Other woods such as Birch, Cherry, Maple and Cedar can be safely air dried to about 20% mc before going into the kiln. On average we had over 600,000 board feet in our kilns at any point in time, average time in the kiln was an average of 18 days (including air dried), Oak would run about 40 days from dead green, aird dried would take 10 to 15 days depending on the various factors. So figure 10 million feet a year.

Wood that went into the kiln dead green always gave a higher yield than wood that was air dried. The only reason that we air dried at all was to increase volume to meet production demands, with just 16 kilns we had to be able to push the average run times down as much as possible.

[David Hawkins]

Hi David

thank you for all the usefull information so far. It's alway's betther to hear from someone who has experience with the matther.
At this moment we are still buying from our current sawmill. both Quartersawn & dosse sawn wood.

But we prefere the look of quartersawn, but we don't like the flakes in the wood. So I was thinking of rift sawing. But nobody can really give me a good explantion of this. Is it even possible to have the structure of quartersawn but without the flakes?

If you are limited to Oak then the medullary ray flecks will be there, personally I find it very attractive but and my wife doesn't like them at all. They are part of the cellular structure of Oak. Quatersawn lumber tends to be more stable dimensionally but more expensive to produce than plain sawn. Rift sawing is the least efficient way to saw (most expensive). The medullary ray flecks will be most apparent in Rift sawn oak and least apparent in Plain sawn Oak. The closer the grain is to vertical the more they show up, it is the nature of the material.

See this page for a general explanation of sawing methods: http://www.northendhardwoods.com/201...t-sawn-lumber/

[Scott T Smith]

If you are limited to Oak then the medullary ray flecks will be there, personally I find it very attractive but and my wife doesn't like them at all. They are part of the cellular structure of Oak. Quatersawn lumber tends to be more stable dimensionally but more expensive to produce than plain sawn. Rift sawing is the least efficient way to saw (most expensive). The medullary ray flecks will be most apparent in Rift sawn oak and least apparent in Plain sawn Oak. The closer the grain is to vertical the more they show up, it is the nature of the material.

See this page for a general explanation of sawing methods: http://www.northendhardwoods.com/201...t-sawn-lumber/

One thing that confuses this topic is that there are different definitions of "rift" sawn oak, and they are opposite one another. References for Rift include lumber with growth rings intersecting the face of the boards between 30 - 60 degrees, another definition states 45 - 70 degrees, and an old FPL publication listed "pure rift" as having a 90 degree orientation, as David references above.

In Bruce Hoadley's book "Understanding Wood", on page 14 he defines "comb grain and rift grain as being 45 - 90 degrees, but also defines Quartersawn and Quarter-grain the same way. He does not define "rift sawn" in his book, but does define "bastard grain" as that with growth rings orientated between 30 - 60 degrees of the surface.

The NHLA (National Hardwood Lumber Association) does not define Rift Sawn lumber.

The only industry recognized standard that I am aware of for rift sawn lumber is in The Architectural Woodworking Standards manual published by the Architectural Woodwork Institute in the USA, and Architectural Woodwork Manufacturers Association of Canada Woodwork Institute. The AWI specification for Rift sawn lumber stipulates a 30 - 60 relationship with optimum being 45 degrees. This specification can be found in Section 3, Lumber, Appendix B of Edition 1 of the 2009 Architectural Woodwork Standards manual, Page 449.

Dominique, in order to minimize the ocurrence of the medullary ray fleck, your sawyers will need to analyze the medullary lines visible on the ends of the logs and mill accordingly. It is difficult if not impossible to mill a log so that it only produces rift sawn lumber (AWI spec).

As David has stated, you will have the least amount of degrade in 4/4 and 5/4 oak if you dry green lumber in a kiln as soon as possible after milling. If you are milling thicker oak - such as 8/4, then air drying for several months may be financially justifiable.

My own experience drying quarter and rift sawn oak is that it requires about 20% longer drying times than flat sawn oak lumber. I would advise against milling your logs first into thicker beams / planks and then air drying them, as that will ultimately lead to increased degrade in the form of cupping and surface checks in the resawn boards. With quartersawn oak, you are better off milling about 12% thicker than the targeted rough sawn dry lumber thickness as opposed to milling extra thick and resawing. For some species this approach works fine, but not with oak.

There can be increased waste when milling quarter and rift sawn lumber; the extent of which depends upon your milling equipment as well as practices. It requires about 4X more labor to produce quarter and rift sawn lumber as opposed to flat sawn lumber, so you need to be sure that you understand that the production rate will be significantly reduced when compared with milling flat sawn lumber.

One critical ingredient for producing high quality lumber is to source high quality grade logs. Due to the waste involved with the milling process, it's frequently much more cost effective to have the lumber milled near the log source and then transported in board form, as opposed to transporting logs. The reason is that a ton of logs will only produce about 3/4 ton of lumber, and perhaps 2/3 ton of high grade quarter and rift sawn lumber.

[Mel Fulks]

We had a fairly lengthy thread on this some time back. I am familiar with AWI ,recognize them as a force ,...and don't think much of them .As Samuel Johnson said to young man who had asked him to read his book "your work is both good and original...Unfortunately the part that is good isn't original . And the part that is original isn't good". The good stuff in their specs is straight out of the government forest products book . The ever decreasing standards ....are original work. Yes, there are slightly varying definitions of rift sawn. And AWI has the weakest one.

[David Hawkins]

Just another thought if you are planning on sawing your own lumber...

If you are currently buying "Quarter Sawn" lumber from a large producer I suspect that most if not all of that comes from the grading chain and not from the sawyer taking particular care when cutting the log. Most modern "double cut" band saws are set up for flat out production cutting both on the forward pass and taking another board on the "back stroke". The sawyer will generally "square" the log and roll it between passes only to get the best grade from the entire log.

The Lumber Grader than sorts through the boards and has them piled based on his orders. If he has an order for quarter sawn of a certain grade or "grade and better" then when he comes on a board that fits the grade requirements into that pile it goes. While the sawyer may know that Quarter sawn is desired and he may give the log an extra roll to get an extra QS board he will make more money for the mill by going through a higher number of logs. While it is a general truism in the furniture industry that "Labor is cheaper than Lumber" having a bottleneck at the band mill costs way too much.

[Scott T Smith]

We had a fairly lengthy thread on this some time back. I am familiar with AWI ,recognize them as a force ,...and don't think much of them .As Samuel Johnson said to young man who had asked him to read his book "your work is both good and original...Unfortunately the part that is good isn't original . And the part that is original isn't good". The good stuff in their specs is straight out of the government forest products book . The ever decreasing standards ....are original work. Yes, there are slightly varying definitions of rift sawn. And AWI has the weakest one.

Mel, in your experience how do you reconcile the FPL spec from the 1920's manual that states "Pure rift" has growth rings intersecting the face of the board at 90 degrees, versus the AWI spec that states 45 degrees? Those specs are at opposite ends of the quartersawn definition spectrum.

The Forestry Products Laboratory has not defined "pure rift" as a 90 degree grain orientation in any publication since a single drawing in a 1920's publication (that I can find). FPL currently defines quartersawn as 45 - 90 degrees and "bastard sawn" as 30 - 60 degrees, but does not define riftsawn or "pure Rift" (Wood Handbook, Page 3-14, General Technical Report FPL-GTR-190). The only current "official" definition of rift sawn that I have found is the AWI one, which happens to match up with a Purdue University's Extension Office publication from 2007 where they define rift sawn as basically the same as the AWI spec (vertical grain w/o ray fleck). Basically these two specs indicate that rift sawn is the same as "bastard sawn" from current FPL publications.

I'm not trying to argue the point; I have a great deal of respect for your knowledge and history in the industry. I'm trying to better understand the logic behind the different definitions because the inconsistency is something that I have to deal with every day.

Thanks much.

Scott

[Mel Fulks]

Thank you, Scott. Yeah, I guess the only clarity is going to come from a buyer asking what standard the seller uses .And in some cases the seller asking how it's going to be used. I find the spec about vertical grain without fleck strange since the fleck may not EXIST even in a perfect vertical grain piece,so to me if it's vertical grain it's quarter cut. That much could at least be clear. I can understand some modern standards being eased a little with kiln drying ,but don't like the idea of lower standards coming in through official edicts of organizations.