Latest Discussions : Tools & Workshop

John Sparks

11:47AM | 01/21/99

I want to build a hexagonal flower bed out of landscape timbers,but I don't know the angles to cut the timbers on my miter saw. Can anyone help?

bink

04:23AM | 01/22/99
The sum of all interior angles in a regualar polygon is 360 degrees. Divide by the number of angles, hexigon is 6. 360/6 is 60 degrees. The miter cut is 1/2 of of the total angle. 30 degrees. I hope I remember my trig right.

SprungJo

02:00PM | 01/25/99
No, sorry, you only get 360 degrees if you
have four corners. For a hexagon, it's 120
degrees for each of six corners, 720 in all.

So, you want 60 degrees for your miter.

To lay out a regular hexagon, start by using
a compass, or a string with a nail on one
end and pencil on the other. Draw a circle
that will contain the corners of the hexagon.
Pick an arbitrary point to be the first
corner, make a mark, and then put the nail
or compass point there. measure a distance
equal to the radius in both directions to
mark the next two corners. Continue around
both ways from there.

bink

07:24PM | 01/25/99
Sprung]o:
Your are right, I was thinking about something else when I posted the reply. Thanks for correcting me.

BobS

05:41PM | 02/14/99
On Bob Vila'a home page, he answered a question from someone building a gazebo who wanted to know the correct angles for an 8 sided structure. Bob's answer was "the sum of the sides should total 360 degrees" and for the 8 sided gazebo, the angle was 45 degrees but to get the sides to mitre correctly, you cut them at half of the total angle, or 22.5 degrees. Maybe both methods work. Who can get the right answer?

mkgarrison

07:44AM | 02/23/99
Ok, if it works for 90 degrees, it'll work for any angle, right?

4 90's will make a square. Each side piece of material will have a 45 degree angle which will match to another side piece forming a 90 angle. So, for a completeley enclosed 'whatever' each piece will need to be cut at half the 'desired' angle of the joint.

Mike

mkgarrison

07:54AM | 02/23/99
Oh wow! What an embarrasement. Of course, it's 60 degrees.

Mike

sheila bassett

10:56PM | 04/12/99
The sum of the interior angles of a regular polygon with n sides is 180 degrees multiplied by 2 less than the number of sides. So for a hexagon, sum of interior angles is 180 x (6 - 2) = 720.
For an octagon is't 180 x (8 - 2) = 1080.
Each interior angle is the sum of angles divided by the number of sides.
For a hexagon it's 720/6 = 120, for an octagon it's 1080/8 = 135.
Each angle to be cut is half the interior angle. For hexagon it's 60, for hexagon it's 62.5.

master fagin

03:37PM | 04/23/99
Sorry folks but Bink is correct. Three sixty
is constant for all shapes. Think about it. Four corners, each 90 degrees, equals 360 degrees. Six corners, each 60 degrees, equals 360 degrees. Eight corners, each 45 degrees, equals 360 degrees.

Kansaz

10:02PM | 04/23/99
Ok... now for the big picture.

What everyone seems to be missing here is that you are all defining the "interior angles" in two completely different ways.

Some of you think that the interior angles are the ones defined by the inside rim of the shape you are considering. The others think that the interior angles are the ones that are at the very center radiating outward to the corners of the shape (e.g. the part of the pizza everyone inevitably eats first). ALL of you have done your math very well and get A's.

When you consider making the cross-cut of the said landscape timber you must consider whether you are cutting the angle as an additive from zero degrees or a subtractive from 90 degrees. A standard electric chop saw considers a 90 degree cross-cut to be a cut of zero degrees if you use its vernier scale.

Did everyone follow me? I think that none of you would have any problem making the cuts. This here is a case of semantics.

DrJCSlater

10:20AM | 03/08/03
Member Since: 03/07/03
2 lifetime posts
Shelia is correct ... she must make her high school math teacher proud ........ When cutting angles for your octagon (or any polygon), take Sheila's advice....... John

BV007953

01:22AM | 06/01/15
I just built a hexagonal tree ring and I set the miter saw to 30 degrees for each piece of timber...see picture
Hexagonal tree ring

BV007954

01:22AM | 06/01/15
I just built a hexagonal tree ring and I set the miter saw to 30 degrees for each piece of timber...see picture

BV011111

01:20PM | 04/02/16
What angle do I cut to form a triangle out of a 4 foot landscape timber

BV011454

10:51PM | 04/29/16
I just read this in the time it took to make a hexagonal wood frame screen cover for a hexagonal reptile tank. I can say i am a noob when it comes to wood, however i am an avid novice when it comes to metal work. Your formulas are great, and work in theory, however in my normal grind, i find this to work perfect:

360°/6 = 60°
60°/2 = 30°

Im using a speed square and hack saw for my cuts (squared trim) and tried to use your 30° in theory....

Not flush at all. So i thought about it, and where i may have screwed up. Then the light came on.... im using a pivotal point of a 45° square in which x2 makes up 90°. So i divided 30°...

30°/2 =15° to the outside leading long edge of cuts.

Viola!!! Tight joints, and super perfect hexagon that measures square from each corner.

Just food for thought.


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