Proper Angles

[Dan Madill]

Can anyone out there tell me the proper angles to obtain a 6,8, sidied object??...Thanks Again....Dan

[Randy Gillard]

Interior Angle = (n-2)/n*180 where n = number of sides

8 sided = (8-2)/8*180 = 135 Deg.
6 sided = (6-2)/6*180 = 120 Deg.

[MadMark]

Here is a link to a page that will compute the bevel and width given the number of sides and desired diameter. Common values are precomputed and presented as a chart.

The formulas in the other response to this question don't appear to be correct.

The bevel angle is given by dividing 180° by the number of staves. The width of the stave is given by taking the desired diameter times pi divided by the number of staves.

M


Stave Reference and Calculator (http://www.netexperts.cc/~lambertm/Wood/staves.html)

[MadMark]

I'm not sure where you got these formulas, but they are prima facie incorrect. As the number of sides increases the included angle should decrease where your examples have it increasing! Additionally multiplying the 'interior angle' by the number of sides should give 360° - a full circle. Your hexagon example shows 6 sides with an interior angle of 120° - this totals out to 720°!

M

[Randy Gillard]

the angle calculated is the interior angle between any two sides. So the angle increases as number of sides increase. For example, an equalateral triangle has 3 sides, with 60 degrees between each side. A square has 4 sides, with 90 degrees between each side, a pentagon has 5 sides, with 108 degrees between sides...etc. etc.

The angle that gets smaller is the angle measured between the two lines drawn from the center to the intersection of two adjacent sides.

My original post states "interior angle", this may have been confusing to some.

Cheers

Randy

[Danny Proulx]

Hi Dan,
I think the answers are getting way to complicated for a simple question - that is if I understand your question correctly.
I'll use a picnic table as an example. A hexagon or 6 sided table has 6 intersecting sides at 60 degrees or 360 (a full circle) divided by the number of sides.
AN octagon has 8 sides so each intersection is 45 degrees or 360 divided by 8.
When two pieces come together at an angle, the cut on each is half the angle of intersection. So the 60 degree hexagon has two boards cut at 30 degrees to form the intersection. The octagon has two boards cut at 22 1/2 degrees to form the 45 degree joint.
The angles in any multi-sided piece can be found by using the circumferance of a circle (360 degrees) divided by the number of sides required.
Regards,
Danny

http://www.cabinetmaking.com

[Rolly in Westbank]

That's the formula I use. Thanks Danny

[Dan Madill]

Thanx Danny...that's all I was looking for ...nice and simple!!!...Thanks to everyone for their help!!!...Dan

[Robert]

Funny you should ask about proper angles
there is a tool or a set of tools that can set your miter to what ever proper angle you need for
what ever number of sides you need it's from Fasttrak it is called the miter matic www.tufftooth.com (http://www.tufftooth.com)

[Darrell in Oakville]

Dan,

Angles? When I want to cut parts for a regular polygon I just swing my mitre box to the appropriate stop. My Stanley #246 mitre box has stops labelled 4,5,6,8,12 and 24 which are the number of sides of the polygon (except for 24, which I suspect is for sash stools). It's a shame that modern manufacturers don't provide this kind of easy and obvious feature in their tools, eh?

Darrell