why is the grain in a perfect repeating pattern?

[markperr]

David,

It's called bookmatching or bookending depending on whom you talk to.  Sometimes, they'll invert the pattern to give it a different look.  It's very common in large pieces of plywood or laminated wood that uses a decorative face.  Next time you visit Lowe's or Home Depot, take a look at the cabinet grade plywood.  Every piece is created like that.  And yes, you've got it right, trees grown for harvesting are not allowed to grow to diameters that wide.  It would take the better part of a century for an oak tree to get that big and birch and cherry trees never do.

Mark

[Anonymous]

I personally think it is a miracle; i have never seen anything like it before in my life; it is a truly wonderful thing,

Rgds Ian

[FJ and G]

Thanks for explanation. Always assumed they cross cut vice roll cut. But duh, now that I think about it, there aren't many 4 or 8 foot wide trunks!

[vsmith]

Note the piece of birch quarter inch wood I purchased from lowe's. Look at the mirror patterns right and left. How did they do that? Is this some sort of lamination process?

They use this really bigass radial cutter that cuts a log down in much the same way you unroll a tube of wrapping paper, thats why you get repeating patterns in plywood. A single log can be cut into a very very long continuous wood 'ply' about 1/16" or 3/32"  thick. The "ply" is layed flat into sheets, then these sheets are laminated together with the grain direction at 90 degrees to each other in alternating layers. This creates a structural element that has equal rigidity in both up-down and left-right directions. The knots you see on the wood are the same knots just at a different level of the cut "unrolling" of the log.

[FJ and G]

Thanks; don't have it in front of me but believe it's half inch. I do multiple cuts to make the intricate patterns (like you'd do when cutting circles in tiles).

BTW, I limit my metal work to soft metals, brass, aluminum, copper, as I ruined a blade cutting steel.

[markn]

Nice work on the band saw Dave-it that a 1/4" blade you are using?   As for the grain, I am guessing they cut it off while rolling the log

[FJ and G]

Note the piece of birch quarter inch wood I purchased from lowe's. Look at the mirror patterns right and left. How did they do that? Is this some sort of lamination process?

 

Incidentally, I'm using the wood to build a combine and coach, nearly 3 feet long in 7/8n2 and also a Plymouth 7/8n2.

 

Here's a bonus photo showing a piece of truck I carved out for the passenger cars (made 8 of them for both cars). Also, the front portion of the Plymouth is shown here. The teeth contain trays with holes thru them, used for link and pin coupling. The coupler can go in various elevations. I've cut out most of the other parts but just wanted to post them here so you can see the fine details that a bandsaw can do, when using a small tooth metal cutting blade. These parts, incidentally, are pine and for the truck, cedar.