On Tue, 12 Apr 2016 22:46:45 -0500, Martin Eastburn
wrote:

When you have solid board core and a layer on both side that is pretty
it is PLY. Takes 2 to Ply.

Your requirements of this or that or orientation doesn't hold water.

Apple ply is not the same as a fur or pine ply.

Having a solid core is strong. The ply's on the outside is dressing.

I'd call that "veneer", not "plywood".

https://en.wikipedia.org/wiki/Plywood#History


"In 1797 Samuel Bentham applied for patents covering several
machines to produce veneers. In his patent applications, he
described the concept of laminating several layers of veneer with
glue to form a thicker piece – the first description of what we now
call plywood.[1] Samuel Bentham was a British naval engineer with
many shipbuilding inventions to his credit. Veneers at the time of
Bentham were flat sawn, rift sawn or quarter sawn; i.e. cut along
or across the log manually in different angles to the grain and
thus limited in width and length."

You are making commercial product and saying PLY has requirements to be
ply.

I've used Plywood since 51 or 52. They made it in the back shop of the
hardware store. They bought vernier sheets and made their own using
their waterproof glue for all uses.

Martin


On 4/11/2016 7:50 AM, John McCoy wrote:
Martin Eastburn wrote in news:IiEOy.11705$__
:

Plywood is simply veneer over another surface.

Well, no, not really. To be plywood the layers have to have
the grain going crosswise (or, rarely, at 45 degree angles).
That is what gives plywood it's dimensional stability.

Granted there are modern day composites used for "plywood"
cores that don't have grain, but those didn't exist when the
first manufacturers started making plywood.

John