What wood you do?
 

On Feb 8, 10:04*am, The Natural Philosopher
wrote:

You get the best figure from the boards that warp the most.

Not in oak. Oak carries a large premium for quarter-sawn boards, if
the tree is a good grade.

What wood you do?
 

On Feb 8, 9:41*am, Tim Lamb wrote:

The recent gales caused a mature Oak, semi-sound, (around 3'6" trunk) to
assume a horizontal position here.

No idea. Your sawyer needs to open the log first.

I'd halve it, maybe quarter it as it's a decent size, and then decide
on the basis of how good the figure looked. I might even hand-plane a
piece of a quartered log before deciding, just to see it better.

If the figure is good (some of which depends on why it's down), then
I'd quarter-saw it and hope to make furniture-grade boards from it. As
I'd be doing this on a Wood-mizer or similar (a portable railway line
in the woodland, with a horizontal bandsaw on a carriage), I'd do this
by rolling the quartered logs from face to face, not by sawing at 45°.

If the figure was poor, or the trunk was too small to produce useful
width otherwise, I might saw it as through-and-through.

You can sell good quartersawn oak and buy as much flatsawn flooring as
you could want.

What wood you do?
 

Andy Dingley wrote:
On Feb 8, 10:04 am, The Natural Philosopher
wrote:

You get the best figure from the boards that warp the most.

Not in oak. Oak carries a large premium for quarter-sawn boards, if
the tree is a good grade.

It may, but I still think the grain looks crap in quarter sawn.


Its great for frames, not for panels.

What wood you do?
 

On Feb 7, 9:46*pm, Andy Dingley wrote:
On Feb 7, 8:54*pm, Tabby wrote:

I had some no good wood to burn once, and it wouldnt stay alight at
all. Think it was elder.

The only UK wood that burns worse than willow, and it smells nasty
too.

What worked was to create an outer perimeter
of it around the edges of the grate, then build a fire with good wood
in the centre. Gradually the elder all got burnt.

What you mean is that you built a wooden fireplace hearth out of
elder, and it lasted for quite a while.

heh


NT

What wood you do?
 

On Feb 8, 11:52*am, Andy Dingley wrote:
On Feb 8, 5:14*am, Clive George wrote:

On 08/02/2011 00:03, Andy Dingley wrote:

By "slice", I'm guessing you mean a transverse disk. You have pretty
much no chance of this drying without splitting (anything over 4"
diameter). The reasons are slightly complicated to explain in detail,
so if the usual pinheads could please go and read Bruce Hoadley before
arguing, we'd all save some time.

Assuming I don't have Bruce Hoadley to hand, but don't see any reason to
argue, is this because the thin stuff isn't strong enough?

Sorry, but every time this comes up, the usual idiots start arguing
about how they've dried a giant redwood in their shed and it didn't
split.

If you don't have Hoadley, buy it, as it's a damn good book. If you
don't want to do that, the US Forest Products Handbook is on-line for
free (and also available printed and bound for a reasonable price).
OTOH, Hoadley is clearer to read.

Timber drying highlights how much some species differ in some aspects,
but also (surprisingly, to me anyway) how much other aspects are
consistent between species. Moisture content (EMC) has a consistent
relationship with air humidity (RH). Moisture content of a felled log
varies a lot (why felled ash will burn, but others needs to be dried).
Shrinkage with MC varies across species, but total shrinkage from
"felled log" to "dry board" ends up consistent again. The breaking
point of timber varies a lot measured as a stress (i.e. force) but is
consistent as a strain (i.e. dimensional change). The ratio between
tangential, radial and longitudinal shrinkage is consistent, even
though the absolute values vary.

Tangential, or hoop, shrinkage is twice the radial shrinkage (and
lengthways is near zero). If they were the same, then wood would
shrink isotropically, by the same in every direction. The total
shrinkage is about 10% tangentially and 5% radially, for a wet log to
a dry board, for any species. Considering the log as a set of "onion
rings", you should realise that it's now increasingly difficult for
the outer rings to stretch all the way to reach round the inner layers
- and so they crack radially, from excess tension.

Why does it crack? Well the shrinkage will hit 10%, which will
generate some unknown tension in the rings. The tensile force is
enough to break the timber. Now I know neither the force generated,
nor the tensile strength (in force units) of the timber, but I do not
that the maximum strain (as a dimension change ratio) for all timber
is about 8% (AFAIR, can't remember the precise figure). So _whatever_
the species, wet to dry is enough to break a constrained piece of it.

We can avoid this in a few ways.One is a radial cut, or halving the
board. Note also that a log that develops a split early just develops
the one major split. That split relieves much of the tension. Another
way is to take the centre out of the log and to allow it to collapse
as rings.

Another way is to crush the central core of the log (by an
imperceptible amount). If the central core is simply small, then it's
crushed by the larger outer ring. The square law for cross-section
area is such a small core surrounded by a ring an extra inch thick is
far less cross-section than the ring, but for larger cores that extra
inch of ring becomes a progressively smaller cross-section compared to
the core. Small cores get crushed, large cores burst the ring. This
varies by species, as it depends on the species-varying ratio of
tensile strength vs. crush strength. When a species, like lime, is
easy to dry without cracking, it's usually down to this ability to
crush the core slightly.

Elm, noted for its interlocking grain, has a much stronger tensile
strength in a large piece than a small piece, so drying elm will tend
to generate many microcracks, rather than a single big crack.

It's not about varying moisture content radially.

Some good stuf in this thread, could we put some of your posts in this
one onto the wiki?


NT

What wood you do?
 

On Feb 8, 12:36*pm, The Natural Philosopher
wrote:

Not in oak. Oak carries a large premium for quarter-sawn boards, if
the tree is a good grade.

It may, but I still think the grain looks crap in quarter sawn.

That isn't grain, it's figure.

Grain in oak always looks crap, which is why most finishes for it will
try to fill and hide it as much as possible.

Figure in flat-sawn oak (i.e. ring figure, the stuff that's usually
most noticeable in most non-tropicals) is near indistinguishable from
stained ash, which is why my oak-panelled dining room is getting ash
skirting boards (cheaper than oak, and indistinguishable down there).

In quarter sawn oak, you will also see the rather less common
medullary ray figure, aka "ray fleck" or "tiger stripe". This is
caused by slicing the radial rays at a shallow angle, not something
that shows up in many timbers apart from oak. It's a valuable figure,
as you have to have good timber to show it (American oak is better
than English oak) and you also have to quarter-saw to show it at its
best.

You might not like this personally (I do, although some US use of it
as tiger stripe is a bit much), but it's certainly a premium cut, and
priced accordingly.

What wood you do?
 

In message
, Andy
Dingley writes
On Feb 8, 9:41*am, Tim Lamb wrote:

The recent gales caused a mature Oak, semi-sound, (around 3'6" trunk) to
assume a horizontal position here.

No idea. Your sawyer needs to open the log first.

Quite. However the initial choice which I had not mentioned is to sell
it in the bark to my sheep grazier who has an employee doing a *grand
designs* barn:-) They have one of the travelling chain saw mills.

The tree has some deadwood/rot on the sheltered side: roots and
branches. I should know more when I have removed the branches. Not soon
because the ground is soft and it is lying down a steep slope.

I'd halve it, maybe quarter it as it's a decent size, and then decide
on the basis of how good the figure looked. I might even hand-plane a
piece of a quartered log before deciding, just to see it better.

If the figure is good (some of which depends on why it's down), then
I'd quarter-saw it and hope to make furniture-grade boards from it. As
I'd be doing this on a Wood-mizer or similar (a portable railway line
in the woodland, with a horizontal bandsaw on a carriage), I'd do this
by rolling the quartered logs from face to face, not by sawing at 45°.

I know the Wood Mizer. Lot less waste with the band saw. How would you
initially quarter such a large log?

If the figure was poor, or the trunk was too small to produce useful
width otherwise, I might saw it as through-and-through.

I have access to a Lucas Mill. I'm no hand at Ascii art but if you can
imagine the log end on divided into 9 portions by two sets of parallel
lines at 90deg. The right hand ninth would cut horizontally, the middle
vertically and the LH horizontal again. 4/9ths should thus give good
boards.

You can sell good quartersawn oak and buy as much flatsawn flooring as
you could want.

Interesting. I note the word *good*:-)

regards

--
Tim Lamb

What wood you do?
 

On Feb 8, 9:41*am, Tim Lamb wrote:
In message
,
harry writes





On Feb 8, 5:14*am, Clive George wrote:
On 08/02/2011 00:03, Andy Dingley wrote:

By "slice", I'm guessing you mean a transverse disk. You have pretty
much no chance of this drying without splitting (anything over 4"
diameter). The reasons are slightly complicated to explain in detail,
so if the usual pinheads could please go and read Bruce Hoadley before
arguing, we'd all save some time.

Assuming I don't have Bruce Hoadley to hand, but don't see any reason to
argue, is this because the thin stuff isn't strong enough? You say it's
complicated in detail, but could you give an idiot's summary? (mostly I
can see why it would split, but am vague as to why bigger stuff wouldn't).

The there is more moisture in the outer layers of trees than the inner
so it shrinks more, basically. That causes cracks, esp. if the drying
out process is rapid. If rapid, the inner bit doesn't get to dry out
at all.
Drying has to be a slow process to allow the inner to dry.
The timber is cut into planks and stacked with battens between. The
ends are often painted to stop drying beint too quick.
This is air drying. Most timber takes a year for every inch thickness
of the planks to dry out (or "season").

The recent gales caused a mature Oak, semi-sound, (around 3'6" trunk) to
assume a horizontal position here.

At some time in the next few weeks I will have to make decisions as to
its fate. Previously I have engaged a mobile saw mill contractor to
convert to 8"x4" and 4"x4" for construction jobs. This time I am
considering 8"x1" for floor boarding. Due to the nature of in field
milling, cuts of up to 8" horizontal or vertical can be made.

Bearing in mind this is Oak. Is it worth attempting to maximise the
production of boards with growth rings at less than 30deg. or not
bother? Boards will be stacked for air drying.

regards

--
Tim Lamb- Hide quoted text -

- Show quoted text -

The best way to cut oak is radially but it causes lots of waste.
(Wedge shaped bits) This gives furniture quality wood but is only
worth doing if there is medullary ray. (Figured Oak)
If you examine a cut end of your log and you see radial marks (ie @
90deg to the rings, your oak has medullary ray and if cut radially
gives high value wood with a pattern called figuring.
http://en.wikipedia.org/wiki/Medullary_ray_(botany)

The next best thing with less waste is to "quarter saw" it. You saw
the log down once, rotate 90 deg, saw again, rotate the pieces 90 deg
and saw again etc. You get some pieces with figuring and some
without.Or you can first take a couple of full width planks from the
centre and quarter saw the rest.
http://en.wikipedia.org/wiki/Quarter_sawing

English oak when exposed to air turns brown on the heartwood, American
Oak does not.

The heartwood is less prone to woodworm attack and can be cut away
from the sapwood.

The colour can be lightened by exposing it to ammonia gas (fumed oak).

The planks are traditionally sawn 2" thick and stacked on a flat
surface with 2x1 battens 4' apart/ the end grain is painted with oil
paint to stop too quick drying out. They need NOT the have heat or
they may warp.

Figured oak.
http://www.ravenfarm.com/photos/oak%20close.jpg

What wood you do?
 

In message
, harry
writes
The best way to cut oak is radially but it causes lots of waste.
(Wedge shaped bits) This gives furniture quality wood but is only
worth doing if there is medullary ray. (Figured Oak)
If you examine a cut end of your log and you see radial marks (ie @
90deg to the rings, your oak has medullary ray and if cut radially
gives high value wood with a pattern called figuring.
http://en.wikipedia.org/wiki/Medullary_ray_(botany)

The next best thing with less waste is to "quarter saw" it. You saw
the log down once, rotate 90 deg, saw again, rotate the pieces 90 deg
and saw again etc. You get some pieces with figuring and some
without.Or you can first take a couple of full width planks from the
centre and quarter saw the rest.
http://en.wikipedia.org/wiki/Quarter_sawing

English oak when exposed to air turns brown on the heartwood, American
Oak does not.

The heartwood is less prone to woodworm attack and can be cut away
from the sapwood.

The colour can be lightened by exposing it to ammonia gas (fumed oak).

The planks are traditionally sawn 2" thick and stacked on a flat
surface with 2x1 battens 4' apart/ the end grain is painted with oil
paint to stop too quick drying out. They need NOT the have heat or
they may warp.

Right.

Thanks to all who replied on this.

I think the first move after removing the branches must be to find
someone with a long enough chain saw bar to knock off the roots and
expose the butt. If there is serious rotting I'll let the *grand
designs* barn man have it. Otherwise try to maximise the amount of
quarter sawn planks.

Why 2"? Recut to 7/8" finish?

regards
--
Tim Lamb

What wood you do?
 

On Feb 8, 7:00*pm, harry wrote:

English oak when exposed to air turns brown on the heartwood, American
Oak does not.

These two white oaks (Quercus robur in England, Q. alba in America)
are quite hard to distinguish. They both darken (very) slowly on
exposure and any difference between them is no more than the
difference between trees in separate woodlands.

The heartwood is less prone to woodworm attack and can be cut away from the sapwood.

Not only that, the sapwood is much lower in tannin (why the bugs
prefer it) and so won't colour as much, from either time or ammonia.

The colour can be lightened by exposing it to ammonia gas (fumed oak).

Darkened.

What wood you do?
 

On Feb 8, 8:25*pm, Tim Lamb wrote:

Why 2"? Recut to 7/8" finish?

Thin enough to dry fairly quickly, but thick enough that you can resaw
it after drying and after the board has cupped, and you'll still have
two usable resawn boards from the middle of it.

If you quarter-saw instead, it'll cup less and you might initially saw
it to 1" instead.

What wood you do?
 

On 08/02/2011 11:52, Andy Dingley wrote:
On Feb 8, 5:14 am, Clive wrote:
On 08/02/2011 00:03, Andy Dingley wrote:

By "slice", I'm guessing you mean a transverse disk. You have pretty
much no chance of this drying without splitting (anything over 4"
diameter). The reasons are slightly complicated to explain in detail,
so if the usual pinheads could please go and read Bruce Hoadley before
arguing, we'd all save some time.

Assuming I don't have Bruce Hoadley to hand, but don't see any reason to
argue, is this because the thin stuff isn't strong enough?

Sorry, but every time this comes up, the usual idiots start arguing
about how they've dried a giant redwood in their shed and it didn't
split.

heh :-)

stuff

Ta for that - so the answer is that anything will split, which is less
confusing to me.

What wood you do?
 

Once again thanks everyone for replying.

On Feb 8, 12:03 am, Andy Dingley wrote:


By "slice", I'm guessing you mean a transverse disk. You have pretty
much no chance of this drying without splitting (anything over 4"
diameter). The reasons are slightly complicated to explain in detail,
so if the usual pinheads could please go and read Bruce Hoadley before
arguing, we'd all save some time.

You might want to make some backup slices. Then when they've split,
you can bandsaw them into radial segments and rejoin them to make a
fair approximation of a disk.


I was going to mount the mechanism behind with a spindle through the
disc. If I drill a small hole in the center of the rings now that will
stop it splitting by letting the outer rings contract?


I use wax emulsion for sealing, but PVA is probably OK. Certainly if
that's what you've got handy. Some people use emulsion paint.


I've got the pieces down and have painted PVA on the ends. Before I
split them I was wondering is there any advantage to applying PVA the
face where they split?