need help with 6 sides table
ztif
six sided. My brain is not working, there has to be an easy way to mark it
out, isn't there?
Thanks
Chris
Alan McKay
> Hello, I have a round butcher block table which I have to cut so it becomes
> six sided. My brain is not working, there has to be an easy way to mark it
> out, isn't there?
Well, assuming it's a real circle it should be easy enough with a bit
of math. I know next to nothing about woodwork, but my math
is pretty rock-solid ;-)
Finding the centre is your first goal. This can be done with a yard stick
or tape measure. Go across it til you get your longest measurement,
then draw a line. You only have to draw the line near where you think
the centre will be. Do this in several directions and if they all meet
in the same spot, that is the centre. If not, then either you measured
wrong, or it's not really a circle.
Now compute the radius - distance from the centre to the edge.
What you want is 6 triangles and this radius will make up 2 sides
of each triangle. The trick is to compute the length of the 3rd
side of the triangle. You already know the length of two sides,
as well as the angle between them - 60 degrees (1/6 of a circle).
There is a simple formula based on these 3 numbers to compute
the length of the 3rd side, but unfortunately I do not remember
what it is ;-/
Once you have that length - we'll call it X, just mark a point on
the edge of the circle - we'll call it "P" and measure X inches or
centimetres with a yard stick or tape measure. Holding one end
on P, just move the other end until X inches or centimetres
intersects the circle. Mark that point. Continue around the
circle in this manner and if it's a real circle, and if you
measured carefully, it should work out perfectly and you
will eventually have your 6 points marked.
Finally, just draw lines between your points.
I'll try to do a web search to find the only missing formula
you need to find X.
cheers,
-Alan
Alan McKay
> I'll try to do a web search to find the only missing formula
> you need to find X.
Well, at first I thought this was it :
http://www.geocities.com/Hollywood/Hills/6396/ozmath.htm
But alas it is not. But it's cool nonetheless and worth a look
for math geeks ;-) (or Wizard of Oz geeks, I guess)
Hmmm, I can't find the formula, but I'll ask someone
at work and get back to you.
cheers,
-Alan
Jeremy
>> becomes six sided.
> What you want is 6 triangles and this radius will make up 2 sides
> of each triangle. The trick is to compute the length of the 3rd
> side of the triangle.
2sin(x/2). For 60 degrees it is 2sin(30)=1. IOW, each of the six sides
will be exactly equal to the radius.
Jeremy
Bob Lewis
"ztif" <ztifp...@hotmail.com> wrote in message
news:Ky377.134376$qs5.20...@news02.optonline.net...
This is easy to mark out with a compass or divider.
First find the center of the table - to do this mark 3 well spaced points on
the around the edge .
Mark 2 lines (chords ) using the 3 points. Find the midpoints of the two
lines.
Draw two lines perpendicular from the center of the chords. Where they
instersect is the
center of the circle. (You can do this with a ruler and square or a compass
and straightedge)
Set your divider from center to edge.
Place one end of the divider on the edge of the table.
Swing the other end around to mark another point on the edge of the table.
Swing the dividers to mark out a 3rd point.
Repeat for points 4, 5, and 6.
Connect the points and you have a regular (all sides equal) hexagon.
CW
circle. This will give you the spacing on the outer edge of the table. If
this is not clear, send me an email with the diameter of your table and I
will send you a plan in PDF.
--
CW
KC7NOD
"Alan McKay" <amc...@ottawa.com> wrote in message
news:99593702...@ip195.istop.com...
Alan McKay
> 2sin(x/2). For 60 degrees it is 2sin(30)=1. IOW, each of the six sides
> will be exactly equal to the radius.
Doh! Of course! Because 2 sides are the same, and the angle between
them is 60 degrees. There are 180 degrees in a triangle which means
the other 2 angles must also be 60 degrees, which means all the sides
are the same!
I should have seen that a mile away!
BTW, another way to find the centre is to trace the circle on paper.
Then cut it out and fold it in half in several directions to find the centre.
cheers,
-Alan
Lawrence Wasserman
Get an accurate measurement of the radius of the circle, which is 1/2
it's diameter. Now, starting at a point on the circumference of the
circle, swing your yardstick or whatever until the length of the
radius intersects the circumference again. Mark and move the yardstick
to that point, and continue all the way around the circle. If it is
a real circle, and your measure is accurate, the last point will coincide
with the first exactly. If it's off a little, just fudge it,
no one will ever notice. Draw a line between each point and the next
one around the circumference, these are your cut lines.
Alan McKay <amc...@ottawa.com> wrote:
>
> Hello, I have a round butcher block table which I have to cut so it becomes
> six sided. My brain is not working, there has to be an easy way to mark it
> out, isn't there?
--
Larry Wasserman Baltimore, Maryland
lwas...@charm.net
JohnM
Seems to be lots of ways to do it. Here's a recipe from Machinery's
Handbook:
To incscribe a hexagon in a circle:
Draw diameter A-B. (A & B are points on the circle and at the ends of
diameter A-B) With A & B as centers and with the radius of the circle
as radius, draw circular arcs AD intersecting the circle at D, BE
intersecting the circle at E, AF intersecting the circle at F, and BG
intesrsecting the circle at G. Draw lines AD, DE, EB, BG, GF and FA
forming the required hexagon.
WWIC
A little known fact about hexagons: each side is the same length as the
radius of the circle that the points touch.
1) find the center of the table
2) measure the radius (length from center to edge) 24" for sake of
argument
3) pick a random point on the edge of the table and mark it
4) measure 24" from your first point to the edge of the table and scribe
that line.
5) go around the table 5 more times and you'll end up where you started.