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Bob
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 Posted: Sun Apr 18, 2004 10:40 pm Post subject: ?on miter cut. |
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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 |
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Henry E Schaffer
Guest
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| Posted: Sun Apr 18, 2004 10:40 pm Post subject: Re: ?on miter cut. |
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In article <ZWCgc.49462$aD.4129@edtnps89>,
Chris Melanson <cabmaker@telus.net> wrote:
| Quote: |
Could you please go and make a pentagon and see for yourself that 36
Degrees will work for a MITER.
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I'll try it with ASCII-art - and start with one end of one board:
(use Courier or other monospace type font to view):
------------------------------- <- 36 degrees
.
.
.
.
.
.
------------- <- other angle
The "other angle" is 180-36 = 144 degrees, but that isn't important
right now.
Now put another cut end up against this cut end -
------------------------------- <- outside angle = 2 * 36 = 72 deg
./
. /
. /
. /
. /
. /
------------- /
/ /
/ /
/ /
/ /
/ /
The resulting corner is less than 90 degrees - i.e. it turns "inwards"
faster than needed for a square. Clearly for a pentagon, we need it to
turn "inwards" less than for a square.
Where might 36 have come from? My guess is that starting with a
regular square piece of lumber, if you want to end up with 54 degrees,
then the other part will have an angle of 90 - 54 = 36. Depending on
how you feed your wood into the saw - you may have to set your miter
gauge for either one of the two complementary angles. I.e. are you
referring to the angle from the side or the end of the wood being cut.
--henry schaffer
hes _AT_ ncsu _DOT_ edu |
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Bruce
Guest
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| Posted: Sun Apr 18, 2004 10:54 pm Post subject: Re: ?on miter cut. |
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In rec.woodworking
"Bob" <mrbjr@comcast.net> wrote:
| Quote: |
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.
|
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. |
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Bob S.
Guest
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| Posted: Sun Apr 18, 2004 10:56 pm Post subject: Re: ?on miter cut. |
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18°
Bob S.
"Bob" <mrbjr@comcast.net> wrote in message
news:PbidnS6mW7ApVh_dRVn-uQ@comcast.com...
| Quote: |
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
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Chris Melanson
Guest
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| Posted: Sun Apr 18, 2004 11:13 pm Post subject: Re: ?on miter cut. (correct formula) |
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It would be a 36 degree angle
The way to figure out any angle is very simple
you divide 360 by the number of sides then divide your answer in halve to
find out your miter
example for a square : 360 / 4 = 90 then 90 / 2 = 45 degree angle
Example for a pentagon : 360 / 5 = 72 then 72/ 2 = 36 degree angle
Chris
"Bob" <mrbjr@comcast.net> wrote in message
news:PbidnS6mW7ApVh_dRVn-uQ@comcast.com...
| Quote: |
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
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Graham Walters
Guest
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| Posted: Sun Apr 18, 2004 11:15 pm Post subject: Re: ?on miter cut. |
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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
"Bruce" <bruce@nospam.com> wrote in message
news:4082cce7.8359950@news.houston.sbcglobal.net...
| Quote: |
In rec.woodworking
"Bob" <mrbjr@comcast.net> wrote:
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.
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.
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Graham Walters
Guest
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| Posted: Sun Apr 18, 2004 11:17 pm Post subject: Re: ?on miter cut. |
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360 deg / 5 = 72 deg
Divide in 2 for each side of planter 72 deg /2 = 36 deg at each end of
2x4's.
Graham
"Bob" <mrbjr@comcast.net> wrote in message
news:PbidnS6mW7ApVh_dRVn-uQ@comcast.com...
| Quote: |
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
|
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Greg Neill
Guest
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| Posted: Sun Apr 18, 2004 11:28 pm Post subject: Re: ?on miter cut. |
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"Graham Walters" <graham@*spam*aceglow.demon.co.uk> wrote in message
news:c5uk4r$3k7$1$830fa795@news.demon.co.uk...
| Quote: |
5 sided planter, each corner 108 deg therefore 108 * 5 = 540 deg in a circle
I know US and UK gallons are different, didn't realise that degrees were as
well....
Graham
|
The sum of the interior angles of a polygon is (n-2)*180 degrees,
where n is the number of sides. Note that this has nothing to do
with the _central_ angle of a circle.
In the case of a pentagon, the sum of the interior angles is:
A = (5-2)*180 = 540 degrees
So each of the five interior angles of a regular (all sides
the same length) pentagon is 540/5 = 108 degrees.
Equal-angle mitres should be half of this, or 54 degrees. |
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Henry E Schaffer
Guest
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| Posted: Sun Apr 18, 2004 11:51 pm Post subject: Re: ?on miter cut. |
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In article <seEgc.50010$aD.286@edtnps89>,
Chris Melanson <cabmaker@telus.net> wrote:
| Quote: |
... 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.
|
What if I *draw* a line on a board end, so it is at 54 degrees from
the side? (Using a protractor or other angle indicating device.) E.g.
-------------------------------
54 deg -> . |
. |
. |
. |
. ZZZ |
. |
-------------------------------|
and then, using a saw, cut off the part labelled "ZZZ"? What have I set
my saw to?
--
--henry schaffer
hes _AT_ ncsu _DOT_ edu |
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Chris Melanson
Guest
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| Posted: Mon Apr 19, 2004 12:05 am Post subject: Re: ?on miter cut. |
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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
"Greg Neill" <gneillREM@OVE.THIS.netcom.ca> wrote in message
news:SFAgc.1199$Gp4.131415@news20.bellglobal.com...
| Quote: |
"Graham Walters" <graham@*spam*aceglow.demon.co.uk> wrote in message
news:c5uk4r$3k7$1$830fa795@news.demon.co.uk...
5 sided planter, each corner 108 deg therefore 108 * 5 = 540 deg in a
circle
I know US and UK gallons are different, didn't realise that degrees were
as
well....
Graham
The sum of the interior angles of a polygon is (n-2)*180 degrees,
where n is the number of sides. Note that this has nothing to do
with the _central_ angle of a circle.
In the case of a pentagon, the sum of the interior angles is:
A = (5-2)*180 = 540 degrees
So each of the five interior angles of a regular (all sides
the same length) pentagon is 540/5 = 108 degrees.
Equal-angle mitres should be half of this, or 54 degrees.
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Saudade
Guest
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| Posted: Mon Apr 19, 2004 12:15 am Post subject: Re: ?on miter cut. |
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Ah... 36+54=90. You're both right.
"Chris Melanson" <cabmaker@telus.net> wrote in message
news:CcBgc.49418$aD.40272@edtnps89...
| Quote: |
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
"Greg Neill" <gneillREM@OVE.THIS.netcom.ca> wrote in message
news:SFAgc.1199$Gp4.131415@news20.bellglobal.com...
"Graham Walters" <graham@*spam*aceglow.demon.co.uk> wrote in message
news:c5uk4r$3k7$1$830fa795@news.demon.co.uk...
5 sided planter, each corner 108 deg therefore 108 * 5 = 540 deg in a
circle
I know US and UK gallons are different, didn't realise that degrees
were
as
well....
Graham
The sum of the interior angles of a polygon is (n-2)*180 degrees,
where n is the number of sides. Note that this has nothing to do
with the _central_ angle of a circle.
In the case of a pentagon, the sum of the interior angles is:
A = (5-2)*180 = 540 degrees
So each of the five interior angles of a regular (all sides
the same length) pentagon is 540/5 = 108 degrees.
Equal-angle mitres should be half of this, or 54 degrees.
|
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Chris Melanson
Guest
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| Posted: Mon Apr 19, 2004 12:17 am Post subject: Re: ?on miter cut. |
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If you would like the real formula for a MITER it is as follows
A=(360/x)/2
where "a" is the MITER "x" is the number of sides
For interior or exterior angles it would be
A=(360/x)
where "A" is the interior or exterior angle.
CHRIS
"Greg Neill" <gneillREM@OVE.THIS.netcom.ca> wrote in message
news:SFAgc.1199$Gp4.131415@news20.bellglobal.com...
| Quote: |
"Graham Walters" <graham@*spam*aceglow.demon.co.uk> wrote in message
news:c5uk4r$3k7$1$830fa795@news.demon.co.uk...
5 sided planter, each corner 108 deg therefore 108 * 5 = 540 deg in a
circle
I know US and UK gallons are different, didn't realise that degrees were
as
well....
Graham
The sum of the interior angles of a polygon is (n-2)*180 degrees,
where n is the number of sides. Note that this has nothing to do
with the _central_ angle of a circle.
In the case of a pentagon, the sum of the interior angles is:
A = (5-2)*180 = 540 degrees
So each of the five interior angles of a regular (all sides
the same length) pentagon is 540/5 = 108 degrees.
Equal-angle mitres should be half of this, or 54 degrees.
|
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Bernard Randall
Guest
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| Posted: Mon Apr 19, 2004 12:29 am Post subject: Re: ?on miter cut. |
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"Chris Melanson" <cabmaker@telus.net> wrote in message
news:CcBgc.49418$aD.40272@edtnps89...
| Quote: |
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
"Greg Neill" <gneillREM@OVE.THIS.netcom.ca> wrote in message
news:SFAgc.1199$Gp4.131415@news20.bellglobal.com...
"Graham Walters" <graham@*spam*aceglow.demon.co.uk> wrote in message
news:c5uk4r$3k7$1$830fa795@news.demon.co.uk...
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
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.
Chris, |
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 |
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P©WÉ®T©©LMAN
Guest
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| Posted: Mon Apr 19, 2004 12:37 am Post subject: Re: ?on miter cut. |
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"Bob" <mrbjr@comcast.net> wrote in message
news:PbidnS6mW7ApVh_dRVn-uQ@comcast.com...
| Quote: |
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
|
36°
--
© Jon Down ®
My eBay items currently listed:
http://cgi6.ebay.com/ws/eBayISAPI.dll?ViewSellersOtherItems&userid=lamblies&include=0&since=-1&sort=3&rows=25 |
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Swingman
Guest
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| Posted: Mon Apr 19, 2004 12:56 am Post subject: Re: ?on miter cut. |
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"Chris Melanson" wrote in message
| Quote: |
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
|
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.
--
www.e-woodshop.net
Last update: 4/13/04 |
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