riddle me this, riddle me that…
can someone explain:
1. if i’m framing an arch and i know the width of the opening and i know how far down i want the arch to come, what is the formula to determine the radius of the circle???
2. similarly, what if i have the same information and i want to frame an ellipse. how do i do that? (layout/mathematically)
thank you kindly.
Replies
Give this a shot.
Simply go back to grade 4 or 5.
pardon me. i didn't realize i was talking to the great and mighty "Hube". i must've been absent in 4th grade when they went over arcs and ellipses.
ps...I must skipped that class in fourth grade too. Don't get caught up in retribution...it'll just poison your dispostion.
blues right with the formula and on the retribution part. I'm pretty sure that wasnt covered in the 4th grade math class though!
Doug
Doug, that was a great formula for me. I use the regular math one and it makes arch building a cinch.
Over the years I've done them a ton of differnt ways....usually I just freehanded them till they looked right.
blueWarning! Be cautious when taking any framing advice from me. Although I have a lifetime of framing experience, all of it is considered bottom of the barrel by Gabe. I am not to be counted amongst the worst of the worst. If you want real framing information...don't listen to me..just ask Gabe!
Your right,You went to the wrong school. It is'nt taught in Reform school.
Gee, thats quit the comeback
And people say your not that quick.
Guess I didn't make that 4th grade math class either...
Hube ...
quit blowing smoke...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Me thinks maybe the focus of Hube's remark was because he didn't know the answer himself, probably missed that class himself.
What the hell is going on in the schools, everybody skipping math class at the 4th grade level, don't you people know that you have to have a good foundation in order to advance in mathematics!
Its no wonder all the other countries are passing us up, they don't skip school.
Doug
BTW, you back home?
Doug, I didn't actually skip fourth grade...but...there were some cute chicks in the class that I musta been watchin instead of the board!
blueWarning! Be cautious when taking any framing advice from me. Although I have a lifetime of framing experience, all of it is considered bottom of the barrel by Gabe. I am not to be counted amongst the worst of the worst. If you want real framing information...don't listen to me..just ask Gabe!
THAT LEVEL OF MATH iirC WASN'T 4TH GRADE LEVEL....
damn caps lock...
TX/NM border...
hey everyody ...
Ruby is fine...
rube doesn't know better
.
he skipped the humanities class all his
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
IMERC
I know that I wasn't paying enough attention in the 4th grade but I'm sure that that damn nun wasn't covering radii either!
Now I see, your at Ruby's, I'm kinda slow!!!
Edited 12/20/2004 6:07 pm ET by Doug@es
No geometry sense, but lots of religion, i'll bet
no...
called when I passed thru /by...
Texline....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Sorry, I've never smoked a day in my life.
Must be your clouded brain effecting your eyesight
QUITE is spelled with an E on the end.
QUIT , meaning to stop or cease. (which you must have done in the 3 rd grade)
Sorry Hube, I'm the worst speller in the world, and spell check cant catch them all.
That's why I went to college for math and comp. science.
I'm fairly sure that your mouth is doing all your thinking for you, there isn't one person on here that believes that finding the radius of an arc was covered in the 4th or 5th grade.
Try that thinking thing next time your mouth starts to wonder.
Doug
It all depends on the Schooling systems in your area.
Oh wise one, why don't you elaborate
Bull Hockey....
and now yur gonna tell us you had CAC III by 7th grade...
so when was physics...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Wow, right ,how did you know that.
And Physics was taught the year earlier, sorry.
I gotta get me new boots and a snorkel....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
way toooooooooooooooo much to shovel............
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
I think with Hube the first liar never stands a chance!
I thought the same....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Half the width of your opening is your radius for an arch.For an ellipse, try half the height, or get an oval cutter at your local wood working store.Wonderful tool.
I do fine in the arch department...
need this be posted to somebody else...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Next
Too deep for ya...?
get someone to make you a pair of stilts
Your right, you were absent, I never seen ya neither.
Anybody who writes "your" when he means "you're" probably shouldn't be commenting on other people's school attendance.
YOU'RE = you are
YOUR = possession
Oh, you do know the difference. So you have no excuse at all for picking the wrong one.
Well, why not jump into this one as our school always beat the Roman Catholic schools at both basketball and math, not even to mention public schools. <G> (Went to LCMS Lutheran grade school).
Don't know about 4th grade, but definetely knew basic circumferential relationships in 5th grade, and remember 6th grade when we were given task of finding out how far the earth moved around the sun in one month (same arc problem). Also recall having to discuss electron orbits and how small the radius and circumference numbers were, which was an introduction to scientific notation.
Also recall we had 9" asphalt tile in the classrooms, one of the math problems was how many yards of carpet would it take to cover it (we could count tiles to get the room measurements, and were supposed to do this without pencil or paper even)
I wasn't going to say anything about your "go back to grade 4 or 5" remark but I think I will. When someone, anyone, asks a question the best and polite thing to do is answer them the best you can. Off handed mean remarks discourage questions, I don't know if you meant to do that but show more thoughtfulness next time. That was a sincere question it deserved a sincere answer. DWT
Oh oh.....
blueWarning! Be cautious when taking any framing advice from me. Although I have a lifetime of framing experience, all of it is considered bottom of the barrel by Gabe. I am not to be counted amongst the worst of the worst. If you want real framing information...don't listen to me..just ask Gabe!
And my "sincere "reply was....go back to 4th or 5 th grade."
And, obviously, if this cant be accompished, maybe some reading up on some of the math /geometry books,etc that are available would give the answer.
For a good ellipse reference go to http://www.josephfusco.org/Articles/Ellipse/Ellipse.htm and
http://mathworld.wolfram.com/Ellipse.html
Edited 12/18/2004 3:14 pm ET by TIMUHLER
People can mean lots of different things with terms like "arches"; the exact geometry depends on the style of the architecture.
Thebozer....your in luck...that question was answered just recently by...I think...Joe Carola!
I hope I'm crediting the right person.
When I saw his formula, I realized that it would be very helpful to me, since I was just starting a job that had a ton of them and I didn't really know how to do it using a formula.
Now.....let me try to remember, before I go chase down the info.
Forget it...I'll just go cut and paste.
Here's Joe's posts....I was right...THANKS AGAIN JOE! Those formulas were very helpful.
You said your rafter length is 144" and the depth or height of the curve is 12".
You would take your Chord Squared ÷ 8 x Height + Height ÷ 2
Chord = 144"
Height = 12"
Formula - [C² ÷ 8xH] + [H ÷ 2] = Radius
144 x 144 = 20736
8 x 12 = 96
20736/96 = 216
12/2 = 6
Answer - 20736/96 = 216 + 6 = 222" = Radius
Using a Construction Master Pro Trig Plus III.
Enter 144 [Inch] [Run]
Enter 12 [Inch] [Rise]
Press [Conv] [Diag] Returns 222" = Radius
There you go Thebozer...compliments of Joe Carola!
blue
ps...I must skipped that class in fourth grade too. Don't get caughy up in retribution...it'll just poison your dispostion.
Warning! Be cautious when taking any framing advice from me. Although I have a lifetime of framing experience, all of it is considered bottom of the barrel by Gabe. I am not to be counted amongst the worst of the worst. If you want real framing information...don't listen to me..just ask Gabe!
I will throw out another system which works mechanically and actually gives you a full sized drawing faster than you can normally look up the mathematical formulas. You take a pair of straight edged boards (plywood rippers work well) that are at least a foot longer than the width of the arch. You place a nail at the lower edges of the arch (or on a layout board in a position representing these points). You then place a third nail at the highest point of the arch (centered of course). Set the two legs of your straight edged boards so that they rest against the top of the two lower nails and overlap at the peak resting against the nail that marks that position. Now screw or staple the two legs together at the peak where they overlap to make a rigid vee shaped unit. Remove the nail at the peak and hold a pencil or scriber in that position. Slide the corner down until your marker reaches one of the lower nails and then slide it back up and down until you reach the nail on the other side. This will describe an ellipsoid arch that has the proper height and width to form the arch you are intending. If your arch is half as tall as it is wide it will give you a semi-circle but in that special case you could draw it with a compass system more accurately.
Another variant is to place your three nails as stated and get a long, thin, lithe, flexible strip of wood and bend it around the three nails. This will give you some sort of curve, perhaps spline.
~Peter
Martha Stewart wants a toy HO train set and 462' of track for Christmas. Er, "Good Holiday Cheer" season.
This my help you out a bit as well.
http://www.josephfusco.org/Tips/tip0018.html
Edited 12/18/2004 5:51 pm ET by Flash
You asked...."what state did I attend school in"..... the answer is..."with a clear, willing to learn, open mind". (that was the state ,lol, I attended school in.
Also, if you look again at my post (# 3) on this subject, I never said it was TAUGHT in grades 4 or 5. I said ..."simply GO BACK to grade 4 or 5.
That 's where the basics of Math/Geometry are taught.
But it would prove to be starting point for more bigger and more intricate solutions.
After many years of absence in math and Geometry ,in order to pick up on it again one would be best to start at a lower level and work on up to the problem at hand.
Ever hear of the phrase...." you got to learn to creep before you learn to walk "...
And I'm not trying to stir the pot.
it's too thick to start with.
I'll stir a little for fun, not aimed at any previous comments in particular.
Did a web search on K-12 curriculum, etc. Wisconsin state curriculum has geometry (basic circle stuff like talked about here) starting in the 6th grade. Found very few web sites for public schools that detail by grade curriculum, probably did not search well enough in a 5 minute search (e.g., not a single google hit on ( "grade school" "educational curriculum"). Found a few private schools with quotes like "near 100% of graduates are accepted at upper level Ivy L schools" that apparently start 'circular' studies in 1st grade - tried to find a tuition cost for one of those, unsuccesful, but did see a student teacher ratio of 8:1.
Interestingly, the WI school system has a 5th grade computer class that lists making multiplication tables up on spreadsheet. Found that level of 'expertise' interesting, as the son of a friend wrote a working word processing program in computer language on the old Trash 80 computer when he was 10 YO.
If anything not 'fun' about this addition, it maybe is a comment on the sad state of much of education nowadays with diminishing returns on investment.
In case your original question is still unanswered, I came up with a solution for the constant-radius arch.
Solving for the radius, R
R = (x^2 + y^2) / 2x
where y is half the door width
and x is the vertical height of the arch
For example, if you have a 30" wide door, and you want the arch to rise 6", then x=6 and y=15.
Solving for R, you get R = (6^2 + 15^2)/2*6 or R=(36+225)/12 or R=21.75"
As to Hube's contention that this problem can be solved using 4th or 5th grade geometry, I disagree. Not to toot my own horn, but when I was in the 5th grade, I was placed in the 8th grade classroom for math. After that, the school just handed me an algebra book and put me in a room by myself.
The above problem would have an easy geometric solution if the radius were known. However, when unknown, I had to resort to an algebraic solution. And I don't think algebra is typically introduced until the 8th or 9th grade. [If anyone is interested, finding the solution simply involved identifying a right triangle and then using the a^2 + b^2 = c^2 thing (Pythagorean theory, I believe).]
Hube -- if you can describe a geometric solution to the problem (one that doesn't involve trial and error), I'd love to hear it. I'm not saying it doesn't exist; but it's not at all apparent to me, at least.
Please read my reply - #45
Also, look again at post #3.
It says go back to grade 4 or 5. (meaning, get some books,etc on it and work up)
it does not say it was taught in these grades., but its sure a good starting point for someone who has forgotten the basics of math/geometry.
Edited 12/22/2004 2:41 pm ET by Hube
Hube,
When I read your post #3, I sure didn't interpret it as being anything other than a slam. However, if you say your intention was just to direct the poster to go back to the basics and work out a solution, then I'll give you the benefit of the doubt. I know from personal experience that it's easy for others to misinterpret written comments at the boards.
Was notposting to you Bro.
Posting to the thread.Hopefully to Hube who needs some help.
Hube comunicates this way often....
it's called "b!tch Baiting".........
he's trying for a verb slot here and succeding....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Maybe we can hook him up with Bob. :)
Bob would eat him alive!
Regardless of what you think of Bob's posts, there is no substance in Hube's.
Doug
The other verb?????
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Sorry -- apparently I'm too dense to get this joke tonight. Can you give me a hint?
some of the nouns here have been using a style that makes them a verb...
ain't a joke...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
I think it was about the fourth or fifth grade that I learned how to punch an arrogant wise-azz in the nose. Just thought I'd share. Have a great Christmas! LOL
is there a line forming?????
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Hube
I got out of high school with nothing more than general math(math for daily living). Only had one year of math in high school, thank god its changed.
Went to college in my late 20's early 30's, I have a degree in math/CS.
I didn't have much of a math foundation, certainly didn't have any geometry/trig. My first college math class was college alg, up hill from there on out.
Your reply to go back to the 4th or 5th grade seemed like nothing more than an attempt at being a dickus.
Doug