So I've got one big plank of walnut out of which I'd like to make a
round table. I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38" diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get? Is
there any sort of formula I can use to see what my options are?
Thanks.

JP

On May 21, 9:31*pm, Jay Pique wrote:
So I've got one big plank of walnut out of which I'd like to make a
round table. *I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38" diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) *Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get? *Is
there any sort of formula I can use to see what my options are?
Thanks.

JP

Hey JP, (left arm is in a cast following surgery. all typing from
this point will be lower case)
i don't follow your reasoning very well. how thick is it? why not
cross cut it to 32 long, rip and edge joint tp 11 wide each, and edge
glue. you'd have a 33x32 plank which would produce an almost 32 inch
diameter table. the waste would be minimal compared to making the
strips you refered to and cross cutting and gluing stuff up.

marc( who still managed to turn a cocobolo pen tonight- post surgery-
to give to his doctor tomorrow when he removes the drain from my arm.
that cast had my left arm set at the perfect angle for holding the
cutting tools. what's that saying? " when life hands you lemons, make
pens". well, something along those lines anyway.)

In article , marc rosen wrote:
On May 21, 9:31=A0pm, Jay Pique wrote:
So I've got one big plank of walnut out of which I'd like to make a
round table. =A0I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38" diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) =A0Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get? =A0Is
there any sort of formula I can use to see what my options are?
Thanks.

JP

Hey JP, (left arm is in a cast following surgery. all typing from
this point will be lower case)
i don't follow your reasoning very well. how thick is it? why not
cross cut it to 32 long, rip and edge joint tp 11 wide each, and edge
glue. you'd have a 33x32 plank which would produce an almost 32 inch
diameter table. the waste would be minimal compared to making the
strips you refered to and cross cutting and gluing stuff up.

Sorry, but that's incorrect. The waste from this method would in fact be a
very large fraction of the total. He's starting with, as he noted, 1152 square
inches; a circle with a diameter of 32 inches has an area of only 804 square
inches, so the waste is 348 sq in or a bit over 30%. That's not "minimal" by
any reasonable definition.

Ripping into 4" strips (actually about 3-7/8 after kerfs and edge jointing)
wastes only 3/8" x 96" = 4 square inches. Obviously there will be more wasted
than that when the strips are cut to length and glued up, but it won't be
anywhere near 30%.

Jay -- I'm sure there is a formula, but it won't be simple to derive. You can
get an approximation, though, from the following:

The largest circle theoretically possible, with zero waste, would have radius
= sqrt ( 1152 / pi ) = 19.15 -- so a bit over 38" diameter is the theoretical
maximum.

I think as a practical matter you're going to be limited to 36" diameter (nine
strips). Best to draw it out on graph paper, I think.

hey Doug,
no argument here on the math but i'm looking at from a practical
point of view. unless there is a real need or desire to get the
largest diameter out of that plank i think the time and effort put in
to cutting and gluing all those strips would be better used making the
table with the least amount of cuts. plus, i think its appearance
would be enhanced by showing the wider grain pattern of the 11 inch
boards.
sure, that's just my opinion/approach to this but i think it would
turn out easier to construct and finish, and still be a reasonably
large circle.
i've made several circular side tables but none that large, twenty-
two inches was the largest and i used a sliding dovetail to join the
pieces. these were teak tables and i wated a glueless joint.

Marc

Jay Pique wrote:
========================================
So I've got one big plank of walnut out of which I'd like to make a
round table. I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38"
diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get?
Is
there any sort of formula I can use to see what my options are?
==================================

It's paper doll time, AKA: Graphical solution.

You are going to want to cut this 12"x96" piece into three (3) pieces
that are 12" wide but of varying lengths.

The lengths will be determined by graphical layout using some graph
paper and 1/4"=1" scale.

Assume you want to get a 36" finished dia. top,cut the first blank
37"-38" long.

If you joint and rip this board, you should yield three (3) pieces
that are 3-1/2" wide which yields a 10-1/2" glue up.

You might get lucky and get 3-3/4" pieces, thus an 11-1/4" glue up.

The 2nd piece will be about 32"-34" determined by graphical solution.
(Allow 1/2" min on each end for enough waste when trimming final blank
to size.)

Rip and joint two (2) pieces say 5-1/2" to 5-3/4" each.

Place one board left, the other right of center board and glue-up.

The 3rd piece will be about 18"-20" determined by graphical solution.
(Allow for enough waste when trimming final blank to size.

(The 18-20 is strictly a guess, but it is in the ball park)

Rip and joint two (2) pieces say 5-1/2" to 5-3/4" each.

Place one board left, the other right of center board.

Finally, there will be a 4th piece which will be short.

Plan this closely since you will be near the edge with a short piece
and you are running out of material.

May want to rip into 2-1/2" strips and then add to glue up.

The above will allow the glue up in stages, not the hole thing at
once.

When glued up an cured, head to the commercial drum sander and sand to
size, then trim with a router and a circle template..

Have fun.

Lew

"marc rosen" wrote:
=======================================

... largest diameter out of that plank i think the time and effort
put in
to cutting and gluing all those strips would be better used making
the
table with the least amount of cuts. plus, i think its appearance
would be enhanced by showing the wider grain pattern of the 11 inch
boards.
===================================
My gut tells me that an 11-1/2" wide plank, sooner or later, is going
to cup.

Lew

On May 21, 9:31*pm, Jay Pique wrote:
So I've got one big plank of walnut out of which I'd like to make a
round table. *I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38" diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) *Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get? *Is
there any sort of formula I can use to see what my options are?
Thanks.

I'd lay it out in SketchUp. And there is a "formula", it's called
calculus.

R

On May 21, 6:31*pm, Jay Pique wrote:
So I've got one big plank of walnut out of which I'd like to make a
round table. *... the plank is 12x96 ... *Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get? *


Ignoring saw kerf width, the straightforward way to saw
a rectangle into parts of a circle is to make a series of
triangles and assemble like slices of a pie.

With that strategy, the board length is a multiple of the
radius achievable, 96" board can give 32" circle
table. Rip to 4", make16" lengths, cut those along
the diagonal to make 4x16 right angle triangles: 14 degrees
each. It takes 26 sections to make the full 360 degrees
(actually a bit more), but there's some wood left,
about 80" by 4", so you could lap-joint two 40" boards
to make an X, put a quarter-circle of wedges in each
90 degree corner, and get (about) 36 to 37.6" of table
after trimming it down.

You will learn a LOT about gluing and clamping before
this table is done. Splines or biscuits are recommended.
Practice on scraps.

A table saw for accurate 90 degree cutting is essential.

The related problem with 6" ripped boards is ... left as an exercise.

On May 21, 10:44*pm, (Doug Miller) wrote:
In article , marc rosen wrote:





On May 21, 9:31=A0pm, Jay Pique wrote:
So I've got one big plank of walnut out of which I'd like to make a
round table. =A0I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38" diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) =A0Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get? =A0Is
there any sort of formula I can use to see what my options are?
Thanks.

JP

Hey JP, (left arm is in a cast following surgery. *all typing from
this point will be lower case)
i don't follow your reasoning very well. *how thick is it? *why not
cross cut it to 32 long, rip and edge joint tp 11 wide each, and edge
glue. *you'd have a 33x32 plank which would produce an almost 32 inch
diameter table. *the waste would be minimal compared to making the
strips you refered to and cross cutting and gluing stuff up.

Sorry, but that's incorrect. The waste from this method would in fact be a
very large fraction of the total. He's starting with, as he noted, 1152 square
inches; a circle with a diameter of 32 inches has an area of only 804 square
inches, so the waste is 348 sq in or a bit over 30%. That's not "minimal" by
any reasonable definition.

Ripping into 4" strips (actually about 3-7/8 after kerfs and edge jointing)
wastes only 3/8" x 96" = 4 square inches. Obviously there will be more wasted
than that when the strips are cut to length and glued up, but it won't be
anywhere near 30%.

Jay -- I'm sure there is a formula, but it won't be simple to derive. You can
get an approximation, though, from the following:

The largest circle theoretically possible, with zero waste, would have radius
= sqrt ( 1152 / pi ) = 19.15 -- so a bit over 38" diameter is the theoretical
maximum.

I think as a practical matter you're going to be limited to 36" diameter (nine
strips). Best to draw it out on graph paper, I think.- Hide quoted text -

I'm pretty sure I'm going to rip the plank into ~4" strips, so that
will make my job easier. I'm going to play around in SketchUp, like
someone mentioned, to see about exact cut-lengths. I could even try
to make my cuts on an angle to help minimize waste. I wonder if the
big millwork shops that make (lots of) round tables glue up and cut to
minimize waste? Hmmm....

Thanks for the replies, everyone.

JP

Jay Pique wrote:
I could even try
to make my cuts on an angle to help minimize waste.


That makes perfect sense since you will be flipping
them, in order to stagger the end grain (cupping).


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On Fri, 22 May 2009 19:04:23 -0700 (PDT), Jay Pique
wrote:

I wonder if the
big millwork shops that make (lots of) round tables glue up and cut to
minimize waste? Hmmm....

I imagine there would be some of that, but there would be a point at
which the increased labor cost to minimize waste would exceed the cost
of material conserved. And, I'm also sure that optimum, minimum total
cost point would be quite different between a hobby for fun shop and a
production for profit shop.

Tom Veatch
Wichita, KS
USA

On May 22, 10:34*pm, Tom Veatch wrote:
On Fri, 22 May 2009 19:04:23 -0700 (PDT), Jay Pique

wrote:
I wonder if the
big millwork shops that make (lots of) round tables glue up and cut to
minimize waste? *Hmmm....

I imagine there would be some of that, but there would be a point at
which the increased labor cost to minimize waste would exceed the cost
of material conserved. And, I'm also sure that optimum, minimum total
cost point would be quite different between a hobby for fun shop and a
production for profit shop.

Tom Veatch
Wichita, KS
USA

Very true. Highly dependent on labor costs and costs of materials.
At work I make tables from reclaimed wood, which easily tops $10/
bdft., and let me tell you that I'm not getting rich! (Monetarily,
anyhoo)

JP

"Jay Pique" wrote in message
...
On May 21, 10:44 pm, (Doug Miller) wrote:
In article
, marc
rosen wrote:





On May 21, 9:31=A0pm, Jay Pique wrote:
So I've got one big plank of walnut out of which I'd like to make a
round table. =A0I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38" diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) =A0Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get?
=A0Is
there any sort of formula I can use to see what my options are?
Thanks.

JP

Hey JP, (left arm is in a cast following surgery. all typing from
this point will be lower case)
i don't follow your reasoning very well. how thick is it? why not
cross cut it to 32 long, rip and edge joint tp 11 wide each, and edge
glue. you'd have a 33x32 plank which would produce an almost 32 inch
diameter table. the waste would be minimal compared to making the
strips you refered to and cross cutting and gluing stuff up.

Sorry, but that's incorrect. The waste from this method would in fact be a
very large fraction of the total. He's starting with, as he noted, 1152
square
inches; a circle with a diameter of 32 inches has an area of only 804
square
inches, so the waste is 348 sq in or a bit over 30%. That's not "minimal"
by
any reasonable definition.

Ripping into 4" strips (actually about 3-7/8 after kerfs and edge
jointing)
wastes only 3/8" x 96" = 4 square inches. Obviously there will be more
wasted
than that when the strips are cut to length and glued up, but it won't be
anywhere near 30%.

Jay -- I'm sure there is a formula, but it won't be simple to derive. You
can
get an approximation, though, from the following:

The largest circle theoretically possible, with zero waste, would have
radius
= sqrt ( 1152 / pi ) = 19.15 -- so a bit over 38" diameter is the
theoretical
maximum.

I think as a practical matter you're going to be limited to 36" diameter
(nine
strips). Best to draw it out on graph paper, I think.- Hide quoted text -

I'm pretty sure I'm going to rip the plank into ~4" strips, so that
will make my job easier. I'm going to play around in SketchUp, like
someone mentioned, to see about exact cut-lengths. I could even try
to make my cuts on an angle to help minimize waste. I wonder if the
big millwork shops that make (lots of) round tables glue up and cut to
minimize waste? Hmmm....

Thanks for the replies, everyone.


I worked in a table shop for a while, we primarily made round
red oak pedestal tables.

We cut all the material for the tops the same length, after glue up
the tops were sanded in the square and cut to round with a bandsaw,
the corners were saved to make glue ups for feet,
very little material was wasted and there was no complex
cutting or gluing for the tops.

There was one semi retired
guy that made roll front bread boxes, shelf brackets and other
widgets and gizmos out of some of the waste, most of what left
as waste was sawdust and shavings.

basilisk

On May 23, 6:27*am, "basilisk" wrote:

I'm pretty sure I'm going to rip the plank into ~4" strips,

(and glue up in grain-parallel fashion to make a round top)

From the point of view of minimizing waste, it might be better to rip
the board
into 5"-5"-2" strips, because edge joining boards will incur the most
waste
when a wide board is near the outer edge of the glue-up. Narrow
boards
at the periphery reduces that waste.

Best design results from making fewest preconceptions/early decisions.

Since you're going to ignore the aesthetics of infinitely narrow strips anyway ...
Use your dado blade to reduce the entire board to sawdust. Make a
circular form 38.25" in diameter and fill it with glue and the sawdust.
Presto! 100% of the board used and no loss due to kerfs.
If you're willing to go thinner you can even get a larger diameter out of it.

Art


"Jay Pique" wrote in message
...
So I've got one big plank of walnut out of which I'd like to make a
round table. I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38" diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get? Is
there any sort of formula I can use to see what my options are?
Thanks.

JP

On May 21, 9:31*pm, Jay Pique wrote:
So I've got one big plank of walnut out of which I'd like to make a
round table. *I've determined that since the plank is 12x96 I have
1152 square inches of area, which equates to just over a 38" diameter
table, (ignoring the realities of loss due to saw kerfs and the
aesthetics of infinitely narrow strips.) *Now assume that I rip the
plank into 3 strips of 4" - what's the biggest diameter I can get? *Is
there any sort of formula I can use to see what my options are?
Thanks.

JP

Bandsaw it into 1/8" or 1/4" veneer.