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My wife would like a 5 sided planter. Just thinks it would look cute?? I am
not a wood worker but, have access to a compound miter saw. What degree
would I need to cut the 2x4's to achieve this? They will each be 27" long.

Thanks for any help or advice.Bob

In rec.woodworking

I can picture a lot of 5 sided planters but probably wouldn't make any with 2x4s. Are you talking about a pentagon with sides perpendicular to the ground? If so, the angles would be 54 degrees each to make 108 degree corners.

The sum of the interior angles of a polygon is (n-2)*180 degrees, where n is the number of sides. Note that this has nothing to do with the__ _central_ __angle of a circle.

In the case of a pentagon, the sum of the interior angles is:

A = (5-2)*180 = 540 degrees

So each of the five interior angles of a regular (all sides the same length) pentagon is 540/5 = 108 degrees.

Equal-angle mitres should be half of this, or 54 degrees.

I suggest you open a drawing package and draw it out as you don't seem to be able to follow the maths. This isn't a matter of opinion; facts is facts.

Bernard R

Thank you, that is exactly what I have been saying. (Did you read my post before you replied?) As my post makes abundantly clear, I know the difference perfectly well. It is now clear that you do also, although your sloppy use of terminology in previous posts made it appear that you did not.

Now just add up those 54-degree angles -- one at each end of each of five pieces, making ten in all -- and get 540 degrees as the sum of the exterior angles in a pentagon, and we'll both be on the same page.

:-)

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

For a copy of my TrollFilter for NewsProxy/Nfilter, send email to autoresponder at filterinfo-at-milmac-dot-com

#### Site Timeline

- posted on April 18, 2004, 6:40 pm

Thanks for any help or advice.Bob

- posted on April 18, 2004, 6:54 pm

I can picture a lot of 5 sided planters but probably wouldn't make any with 2x4s. Are you talking about a pentagon with sides perpendicular to the ground? If so, the angles would be 54 degrees each to make 108 degree corners.

- posted on April 18, 2004, 7:15 pm

5 sided planter, each corner 108 deg therefore 108 * 5 = 540 deg in a circle

I know US and UK gallons are different, didn't realise that degrees were as well....

Graham

wrote:

I know US and UK gallons are different, didn't realise that degrees were as well....

Graham

wrote:

- posted on April 18, 2004, 7:28 pm

The sum of the interior angles of a polygon is (n-2)*180 degrees, where n is the number of sides. Note that this has nothing to do with the

In the case of a pentagon, the sum of the interior angles is:

A = (5-2)*180 = 540 degrees

So each of the five interior angles of a regular (all sides the same length) pentagon is 540/5 = 108 degrees.

Equal-angle mitres should be half of this, or 54 degrees.

- posted on April 18, 2004, 8:05 pm

Ok you go ahead and build it that way and see what you end up with. I will
guarantee you do not end up with a pentagon at all not even a square. Use
some common sense if you use 45 degrees to get a square how the hell do you
come up with 108 degrees??
108 dose not even divide into 360 evenly you end up with
3.333333333333333333333333333333333 and so on show me a 3.33333333333333333
sided object through the rose coloured glasses you wear. and I will sell you
the patent to widgets ok

CHRIS

CHRIS

- posted on April 18, 2004, 8:15 pm

Ah... 36+54. You're both right.

- posted on April 18, 2004, 8:29 pm

I suggest you open a drawing package and draw it out as you don't seem to be able to follow the maths. This isn't a matter of opinion; facts is facts.

Bernard R

- posted on April 18, 2004, 9:50 pm

In rec.woodworking

Bernard R

You are of course right. I've posted a pic on a.b.p.ww to prove it.

Bernard R

You are of course right. I've posted a pic on a.b.p.ww to prove it.

- posted on April 18, 2004, 8:56 pm

"Chris Melanson" wrote in message

It doesn't have to ... what the man wants for his planter box is a "regular polygon" or "convex polygon" ... i.e, the sides and angles are equal.

As you seem to think, a regular polygon does NOT necessarily have the sum of the interior angles = 360 degrees.

An equilateral triangle is a regular polygon where the sum of the interior angles = 180 degrees

A square is a regular polygon where the sum of the interior angles = 360 digress

A pentagon is a regular polygon where the sum of the interior angles = 540 degrees.

Folks are obviously better educated in the UK these days.

It doesn't have to ... what the man wants for his planter box is a "regular polygon" or "convex polygon" ... i.e, the sides and angles are equal.

As you seem to think, a regular polygon does NOT necessarily have the sum of the interior angles = 360 degrees.

An equilateral triangle is a regular polygon where the sum of the interior angles = 180 degrees

A square is a regular polygon where the sum of the interior angles = 360 digress

A pentagon is a regular polygon where the sum of the interior angles = 540 degrees.

Folks are obviously better educated in the UK these days.

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- posted on April 18, 2004, 9:51 pm

In rec.woodworking

Ummm, it was my post that started this and I'm in the great state of Texas, USA.

Ummm, it was my post that started this and I'm in the great state of Texas, USA.

- posted on April 18, 2004, 10:33 pm

"Bruce" wrote in message

Ummm, so am I ... but since you got it right the first time, you obviously weren't included in "these days" with regard to education.

Ummm, so am I ... but since you got it right the first time, you obviously weren't included in "these days" with regard to education.

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- posted on April 18, 2004, 10:03 pm

Could you please go and make a pentagon and see for yourself that 36
Degrees will work for a MITER.
I have CAD programs (IE Auto CAD V- 7 all the way up to 2004) and do know
how to use them. I also am a very experienced cabinetmaker and am more than
capable of making SIMPLE MITERS and using common sense. If you want all five
sides of a pentagon to be of equal length you would have to use a common
MITER of 36 degrees. If you have trouble comprehending that there is no
sense even trying to explain it any further. GO MAKE A PENTAGON AND FIGURE
IT OUT FOR YOURSELF. Also please knock off your condescending attitude about
"Folks are obviously better educated in the UK these days" because you are
only making yourself look foolish with your self righteous comments.

- posted on April 18, 2004, 10:53 pm

"Chris Melanson" wrote in message

Go back and read again what I took exception to.

Go back and read again what I took exception to.

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- posted on April 18, 2004, 11:00 pm

Did you even read the OP.????

and yes "All closed polygons have angles that equal 360 degrees, with the single exception of the triangle family, where those angles equal 180 degrees" as Quoted from CJ

So will you make the bet ? And try making a pentagon setting your saw to 54 degrees or will you apologise and accept that the answer is 36 degrees.

CHRIS

and yes "All closed polygons have angles that equal 360 degrees, with the single exception of the triangle family, where those angles equal 180 degrees" as Quoted from CJ

So will you make the bet ? And try making a pentagon setting your saw to 54 degrees or will you apologise and accept that the answer is 36 degrees.

CHRIS

- posted on April 18, 2004, 11:15 pm

wrote:

The sum of the exterior angles of any closed polygon of n sides is (n - 2) * 180 degrees.

180 for a triangle 360 for a square 540 for a pentagon 720 for a hexagon and so on.

Miter gauge settings measure the difference from 90 degrees (e.g. to make a cut at a right angle, you set the gauge at 90 - 90 = 0 degrees). So to make the proper 54-degree cuts for a mitered joint at the corner of a regular pentagon, you set your miter gauge to 90 - 54 = 36 degrees -- but this cuts a 54-degree angle,***not*** a 36-degree angle. Don't believe me? Make the cut. Then
get a protractor and measure the actual angle.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

For a copy of my TrollFilter for NewsProxy/Nfilter, send email to autoresponder at filterinfo-at-milmac-dot-com

The sum of the exterior angles of any closed polygon of n sides is (n - 2) * 180 degrees.

180 for a triangle 360 for a square 540 for a pentagon 720 for a hexagon and so on.

Miter gauge settings measure the difference from 90 degrees (e.g. to make a cut at a right angle, you set the gauge at 90 - 90 = 0 degrees). So to make the proper 54-degree cuts for a mitered joint at the corner of a regular pentagon, you set your miter gauge to 90 - 54 = 36 degrees -- but this cuts a 54-degree angle,

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

For a copy of my TrollFilter for NewsProxy/Nfilter, send email to autoresponder at filterinfo-at-milmac-dot-com

- posted on April 18, 2004, 11:32 pm

Please read the "OP" and then go and build one
I am getting sick and tired of people without the concept of actually
building something trying to tell me how it is done. You do END up with a 54
Degree angle but do not set your saw for a 54 degree MITER cut. Please learn
the difference between the two.

CHRIS

wrote:

CHRIS

wrote:

- posted on April 18, 2004, 11:52 pm

Thank you, that is exactly what I have been saying. (Did you read my post before you replied?) As my post makes abundantly clear, I know the difference perfectly well. It is now clear that you do also, although your sloppy use of terminology in previous posts made it appear that you did not.

Now just add up those 54-degree angles -- one at each end of each of five pieces, making ten in all -- and get 540 degrees as the sum of the exterior angles in a pentagon, and we'll both be on the same page.

:-)

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

For a copy of my TrollFilter for NewsProxy/Nfilter, send email to autoresponder at filterinfo-at-milmac-dot-com

- posted on April 18, 2004, 11:55 pm

"Chris Melanson" wrote in message

Ahhh , now we're getting somewhere. ... therefore, the correct answer to the OP's question of what angle the cut needs to be:

... is 54 degrees, NOT 36, as you have heretofore been insisting..

The answer to the unasked question "how to cut a 54 degree angle on a miter saw" is to set it to the complementary angle of 36 degrees.

Ahhh , now we're getting somewhere. ... therefore, the correct answer to the OP's question of what angle the cut needs to be:

... is 54 degrees, NOT 36, as you have heretofore been insisting..

The answer to the unasked question "how to cut a 54 degree angle on a miter saw" is to set it to the complementary angle of 36 degrees.

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- posted on April 18, 2004, 11:58 pm

Go build one then start making some since
CHRIS

- posted on April 19, 2004, 1:02 am

Since what?

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