I commented on this in another thread, but decided it might be worth starting a new one on this subject. https://forestryforum.com/board/index.php/topic,69846.msg1055540.html#msg1055540
Have others noticed that the checks in the end of white oak are at right angles to the growth rings, and can be used as a guide to quarter sawing? Just position the blade on the log, or tilt the piece, so that sawing is parallel to the end checks, to get a true QS cut. No need to strain to see the rings.
I learned this the other week while QSing WO, from the owner of a barrel making company who stood next to me a good part of the day. He knew a lot about wood!
Justin posted an excellent photo in the thread referenced above, showing the same thing in Eucalyptus.
(https://forestryforum.com/gallery/albums/userpics/29851/crayon_quaters.jpg)
See from Justin's photo, how the checks in Eucalyptus are also at right angles to the growth rings. One would just tilt this piece up a bit, with the 2-plane clamp, to get a true QS cut.
What is the origin of these cracks? Are they coming from rays at the end of the log drying out quickly?
Can't possibly be new. But it's new to me!
Yip I agree the checking will spread out from the pith and is a good way to spot how things are.
Glad to see my photo came in usefull haha :D
Cheers
Justin
I never thought about this before, but I'm sure it's true with some other hardwoods as well. Great information!
Learning something new every time I log on. Guess I'll stop end-coating anything that's going to be quarter sawn. Thanks for posting.
Quote from: terrifictimbersllc on November 10, 2013, 05:49:01 PM
What is the origin of these cracks? Are they coming from rays at the end of the log drying out quickly?
Typically the end checks on oak logs will follow the medullary rays, and if you mill parallel to the checks you will obtain the highest figure boards.
Here is the photo of the entire log (first one ready to load) which is quite simple with a pith in the middle so checks from the center out.
The next log (and bigger) however has two pith center marks which make the checks go more all over the place (hopefully you can see this in the photo)
Just thought people might like to see the before shot?
The big verticle line on the big log is from the chainsaw marking where I wanted to cut it.
(https://forestryforum.com/gallery/albums/userpics/29851/big_logs_waiting.jpg)
Cheers
Justin
Well, quatersawing, for luthiery and barrel staves was done like this before (still for instrument making)
They would split the wood along thoses cracks, splitting with a froe, which would follow the grain perfectly. Then resaw from that as necessary. Or even carry on splitting. The name quatersawing comes from the fact that ofter they were splitting the log in four, then take two passes from one split face, with a vertical bandsaw and a guide. Then turning it over so the other split face is touching the guide, taking another two passes. The two passes are for bookmatching the two pieces. Then turn over, cut again etc! Untill the width isn't wide enough anymore, then the rest is split for braces, or violin necks in maple etc.
After quartering the log initially, any attempts to saw parallel to the checks will produce wedge-shaped boards. The cracks emanate from the pith hence they are radii. I thought in QSing, after the first cut, we just attempted to approximate sawing parallel to the cracks. - I must be missing something?? Can someone clarify this for me?
Bob
Modified the following response twice since posting it.
Sorry I don't have photos of the WO i was sawing that day. These cracks don't always come from the pith. Only a more extensively dried out log than the ones I was sawing, would have cracks extending from the pith all the way out. These didn't. They had little checks everywhere which were more highly visible than, and consistently perpendicular to, the growth rings. It was a revelation to me that these cracks which were so easy to see were almost always a good guide to 90 degree QSing. This is really the point of my post.
Approximating 90 degrees is a matter of degree (!). For barrel making the customer said the wine barrels would leak (I think he meant evaporate the wine content more rapidly) if one didn't get pretty much 90 degrees. And I have heard that to get good ray fleck for furniture making, one needs 80 degrees or better. True approximating QSing at lower angles than this will still have the parallel grain appearance but not as much ray fleck.
Not sure what you mean Bob by wedge shaped, yes one edge of some of the boards is pointed and this can be edged or not, I didn't, because the customer didn't mind.
In the sawing day mentioned in my OP, I was sawing WO logs over 16" diameter and could be guided by these cracks for all three of the following: 1) breaking down the log initially with cuts across the middle area (i.e. cutting out the middle third for example), then 2) sawing across the remaining other top and bottom pieces to get out the QS across their middles, and 3) sawing the remaining 4 top and bottom pieces by tilting these pieces to cut parallel to the cracks. These remainder pieces, one might call them "corners", from larger logs, have a lot of material still in them, and are ones which I would normally rift-saw for leg stock to accompany the rest of the QS material. In contrast, for the barrel stock I was cutting that day, there was no need for rift sawn material, and pieces as narrow as 1-1/2" wide were desired by the customer. So it was still productive to tilt these pieces to capture more true QS material.
Quote from: kelLOGg on November 12, 2013, 06:18:28 AM
After quartering the log initially, any attempts to saw parallel to the checks will produce wedge-shaped boards. The cracks emanate from the pith hence they are radii. I thought in QSing, after the first cut, we just attempted to approximate sawing parallel to the cracks. - I must be missing something?? Can someone clarify this for me?
Bob
On a big log, you could may be get 4 to 6 inch of quatersawn boards which aren't too bad, from the split face.
Otherwise, see the explanation i've posted above.