In a recent David Mark's episode - he makes a circular mirror, 24" in
diameter.
http://www1.diynet.com/diy/ww_decorative_furnishings/article/0,2049,DIY_14441_2276253,00.html
He starts with 8" wide cherry that's made into a square and sawn into a
circle.
My first question is, what's the formula that takes the final diameter (and
thickness?) of the circle and tells you how wide your stock must be?
My second question is: wouldn't other polygon shapes reduce the width of
wood required? Seems to me a hexagon or octagon would mean thinner wood. Of
course, I'd have to find someway to hide the extra joints.
Simon wrote:
> Does this or does this not look just a little bit dangerous?
>
> http://images.scrippsweb.com/DIY/2003/09/18/wwk301_3fl_e.jpg
Everything on the TS is "a little bit" dangerous.
--
************************************
Chris Merrill
[email protected]
(remove the ZZZ to contact me)
************************************
Do it all the time so what's the problem.
--
Young Carpenter
"Violin playing and Woodworking are similar, it takes plenty of money,
plenty of practice, and you usually make way more noise than intended"
"Simon" <[email protected]> wrote in message
news:[email protected]...
>
> "mttt" <[email protected]> wrote in message
> news:[email protected]...
> > In a recent David Mark's episode - he makes a circular mirror, 24" in
> > diameter.
> >
>
http://www1.diynet.com/diy/ww_decorative_furnishings/article/0,2049,DIY_1444
> 1_2276253,00.html
> >
> > He starts with 8" wide cherry that's made into a square and sawn into a
> > circle.
> >
> > My first question is, what's the formula that takes the final diameter
> (and
> > thickness?) of the circle and tells you how wide your stock must be?
> >
> > My second question is: wouldn't other polygon shapes reduce the width of
> > wood required? Seems to me a hexagon or octagon would mean thinner wood.
> Of
> > course, I'd have to find someway to hide the extra joints.
> >
>
> Does this or does this not look just a little bit dangerous?
>
> http://images.scrippsweb.com/DIY/2003/09/18/wwk301_3fl_e.jpg
>
>
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"mttt" <[email protected]> wrote in message news:<[email protected]>...
> In a recent David Mark's episode - he makes a circular mirror, 24" in
> diameter.
> http://www1.diynet.com/diy/ww_decorative_furnishings/article/0,2049,DIY_14441_2276253,00.html
>
> He starts with 8" wide cherry that's made into a square and sawn into a
> circle.
>
> My first question is, what's the formula that takes the final diameter (and
> thickness?) of the circle and tells you how wide your stock must be?
>
> My second question is: wouldn't other polygon shapes reduce the width of
> wood required? Seems to me a hexagon or octagon would mean thinner wood. Of
> course, I'd have to find someway to hide the extra joints.
yes, other polygons will be a better fit to the circle, the more sides
the closed the fit BUT every joint becomes a problem in getting a
tight joint. I believe an octogon is the better shape for cutting a
circle.
for working out the width of timber required you can use the formula
to create a circle (x2+ y2 = r ) BUT i find it easier to draw it out
full size (i keep a piece of the plain white masonite board used for
walls in wet areas as a drawing board.)
"mttt" <[email protected]> wrote in message
news:[email protected]...
> In a recent David Mark's episode - he makes a circular mirror, 24" in
> diameter.
>
http://www1.diynet.com/diy/ww_decorative_furnishings/article/0,2049,DIY_1444
1_2276253,00.html
>
> He starts with 8" wide cherry that's made into a square and sawn into a
> circle.
>
> My first question is, what's the formula that takes the final diameter
(and
> thickness?) of the circle and tells you how wide your stock must be?
>
> My second question is: wouldn't other polygon shapes reduce the width of
> wood required? Seems to me a hexagon or octagon would mean thinner wood.
Of
> course, I'd have to find someway to hide the extra joints.
>
Does this or does this not look just a little bit dangerous?
http://images.scrippsweb.com/DIY/2003/09/18/wwk301_3fl_e.jpg
"Young Carpenter" <Fiddleronroof*@*juno.com> wrote in message
news:[email protected]...
> Do it all the time so what's the problem.
I guess I am used to European laws about guards, in a professional shop it's
considered illegal to not have the guard in place. I'm also a little bit
prejudiced and wary, because 2 friends, in the last year, were doing the
same thing and had their hands thrown in to tablesaw blades when the wood
kicked on them, these days I will always use the mitre gauge with a clamp
rather than holding it by hand. I like my hands too much.
In article <[email protected]>,
mttt <[email protected]> wrote:
>In a recent David Mark's episode - he makes a circular mirror, 24" in
>diameter.
>http://www1.diynet.com/diy/ww_decorative_furnishings/article/0,2049,DIY_14441_2276253,00.html
>
>He starts with 8" wide cherry that's made into a square and sawn into a
>circle.
>
>My first question is, what's the formula that takes the final diameter (and
>thickness?) of the circle and tells you how wide your stock must be?
>
>My second question is: wouldn't other polygon shapes reduce the width of
>wood required? Seems to me a hexagon or octagon would mean thinner wood. Of
>course, I'd have to find someway to hide the extra joints.
>
>
for a square, the required width of the stock is
"radius of outer circle" - 0.7071 * "radius of inner circle"
the minimum required length is:
1.414 * "radius of inner circle" plus '1 width' (as defined above)
this'll make pieces that go together like:
----|
| |
|----
if you want:
|---|
| |
|---|
the long pieces are 1.414 * "radius of outer circle", and
the short ones are 1.414 * "radius of inner circle"
For hexagon,
thickness is:
"radius of outer circle" - 0.8660 * "radius of inner circle"
length is:
"radius of inner circle" + "1 width" (per above)
"mttt" <[email protected]> wrote in message
news:[email protected]...
> In a recent David Mark's episode - he makes a circular mirror, 24" in
> diameter.
>
http://www1.diynet.com/diy/ww_decorative_furnishings/article/0,2049,DIY_14441_2276253,00.html
>
> He starts with 8" wide cherry that's made into a square and sawn into a
> circle.
>
> My first question is, what's the formula that takes the final diameter
(and
> thickness?) of the circle and tells you how wide your stock must be?
>
> My second question is: wouldn't other polygon shapes reduce the width of
> wood required? Seems to me a hexagon or octagon would mean thinner wood.
Of
> course, I'd have to find someway to hide the extra joints.
Sorry, I don't have a formula available off the top of my head, but you
could make a scale drawing quite easily.
As for the number of sides reducing the width, you are correct. In fact with
an infinite number of pieces you would have no wasted width. Use whatever
you find pleasing. I think I'd rather go with a hexagon or even a septagon
over a square.
-Jack
"mttt" <[email protected]> wrote in message news:<[email protected]>...
> In a recent David Mark's episode - he makes a circular mirror, 24" in
> diameter.
> http://www1.diynet.com/diy/ww_decorative_furnishings/article/0,2049,DIY_14441_2276253,00.html
>
> He starts with 8" wide cherry that's made into a square and sawn into a
> circle.
>
> My first question is, what's the formula that takes the final diameter (and
> thickness?) of the circle and tells you how wide your stock must be?
>
> My second question is: wouldn't other polygon shapes reduce the width of
> wood required? Seems to me a hexagon or octagon would mean thinner wood. Of
> course, I'd have to find someway to hide the extra joints.
Hi:
For a wooden ring with outside radius of R and inside radius of r
divided into N segments, each segment can be cut from a piece of wood
that is x long and y wide, where:
x = 2*R*sin(180/N)
y = R-r*cos(180/N)
Of course, this is strictly theoretical, and doesn't account for
waste.
Regards,
John.
"mttt" <[email protected]> wrote:
>In a recent David Mark's episode - he makes a circular mirror, 24" in
>diameter.
>http://www1.diynet.com/diy/ww_decorative_furnishings/article/0,2049,DIY_14441_2276253,00.html
>
>He starts with 8" wide cherry that's made into a square and sawn into a
>circle.
>
>My first question is, what's the formula that takes the final diameter (and
>thickness?) of the circle and tells you how wide your stock must be?
Width = OutsideRadius - InsideRadius/sqrt(2).
>My second question is: wouldn't other polygon shapes reduce the width of
>wood required? Seems to me a hexagon or octagon would mean thinner wood.
Yes, and klogon is better and megagon better yet<g>.
> Of
>course, I'd have to find someway to hide the extra joints.
Yeah; there also comes a point where saw kerfs outweigh the gain due
to narrower stock (but not at your more pragmatic hexagon or octogon
suggestion).
--
Alex
Make the obvious change in the return address to reply by email.
"Simon" <[email protected]> wrote in message
news:[email protected]...
>
> Does this or does this not look just a little bit dangerous?
>
> http://images.scrippsweb.com/DIY/2003/09/18/wwk301_3fl_e.jpg
Yeah - I noticed the Wedding ring too. Not sure "dangerous" is the word I'd
pick to describe marriage. But at times, it's probably a good fit.