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I am cutting a hip roof with square cut rafter tails(not plumb cut).Is there a way to figure the miter and bevel angles for the hip and the subfacia? Id rather not make a mock up to figure it out.It seems simple, ya right.Any help would be appreciated.Thank you in advance.
Pell
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*
Pell,
What's the roof pitch?
Ken
*It is a 512 ,I am just trying to figure the math out for any pitch roof though.As you know the compound angles change as per pitch.Thank You
*Pell,I'm going to call it a day, but for right now, I'll leave you with this, in case you need the info for tomorrow morning.For a 5/12 pitch, the miter, or face angle on the hip, is 14º. The miter, or face angle on the fascia, is 21º. The bevel, for both the facia, and the hip, is 40 3/4º. Mark the miter angles using a speed square. All of the above angles are rounded to the nearest 1/4 of a degree.Talk to you soonKen
*Oh my God ,You are a cut above Ken Thanks a bunch.Pell
*Ken, I'm somwhat confused by your terms. Or, maybe I'm confused about the question. Do you care to elaborate?blue
*blue,Sure, for a milkbone or 2.When the rafter tails are cut square to the rafters, instead of plumb, as they usually are, all of the jacks and commons are a piece of cake. You just make a square cut at the end of the tail, rather than a plumb cut.The hips rafters are another story. You have to determine the miter angle, or the face angle, and also the bevel to set your circular saw at to make the cut.You might think, that since the hip occurs at a 90º corner, that the bevel should be 45º, but it isn't.For a 5/12 pitch roof, the miter, or face angle, is 14º, using a speed square. The bevel, the tilt on your circular saw, is 40 3/4º.A similar problem occurs at the joint where the fascia meets. As you might expect, the bevel once again, is 40 3/4º, but the miter for the fascia, is 21º, using a speed square.These miter and bevel angles change according to the roof pitch.Now, get the milkbones in the mail, along with the $3500 that you owe me for the steel handrail.Ken
*Okay Ken. I'm now understanding the question. And I almost agree with the numbers. They don't add up though and it's probably because you are rounding or using those terribly inaccurate slow squares.Can you show the math using geometry? If not, trig will do. I'll be sending those milkbones pronto.blue
*blue,What do you mean that the numbers don't add up? What are they supposed to add up to?BTW, the miters and bevels are rounded off to the nearest 1/4 of a degree, as I mentioned earlier.Ken
*Ken, if I knew what they were supposed to add up to, I wouldn't be asking.I'm trying to fit that 14 degree number into a 5/12 equation. Usually, the numbers will fit in somewhere. Tell me, what is the degree of a 5/12 hip? I know the ratio would be 5:17, but can you translate that to degrees? Is it 14 degrees?blue
*blue,In your last post you said "I'm trying to fit that 14 degree number into a 5/12 equation"The problem is, that it won't "fit" into any of the equations that you may know.The equations necessary to figure out the miters and bevels involve square roots, and the trig functions, sine, cosine, and tangent.BTW, 5/12 pitch = 22.6º. and the hip and valleys of a 5/12 roof have an incline of 5/16.97 = 16.4ºBut don't expect the miters and bevels to add up to these numbers.Ken
*I understand Ken...But, somewhere, that number is going to fit nicly into an equation. They always do...How did you come up with 22.6 degrees. I thought it was 22.5. No wonder my octogonal mitres never fit exactly....blue
*blue,I hardly think that the difference between 22.6º and 22.5º, a difference of only 1/10th of 1 degree, would make a difference in your octagon framing. Chances are that you didn't snap it out accurately, or that you're still using that speed square that dropped off the 40th floor 10 years ago and you hammered back into shape..Grab your calulator and divide 5 by 12. The answer is .4166. Now, find the angle that has that number as its tangent, by pressing 2nd, then tangent, assuming that you have a calculator with trig functions on it.That angle is 22.6º, rounded to the nearest tenth of a degree.More accurately, it's 22.61986495º, in case you decide to become a rocket scientist soon.Ken
*Actually Ken, I don't own a speed square. I find them to be the most useless tool ever invented, besides the worm......I don't have a calculator with trig functions. I only use basic geometry for the things I do. The octogon framing thing is just something I noticed over the years. I was under the assumption that the joint was a true 22.5 ( 360 / 8 /2). Isn't there 360 degrees in a circle? Aren't there 8 angles involved in an octogon? Don't you split the angle in half for a mitre?I'm confused...blue
*blue,yes, you're correct.The angle at the octagon corner is EXACTLY 22.5º, or 67.5º, depending how you look at it.Your hear many framers, when cutting these angles on their plates tell someone "cut a 22 1/2º angle, or a 5/12".The point is, that a 5/12 isn't exactly = to 22.5º, but it is very, very, close. If you use 5 on the tongue of your framing square with 12 on the body, you should get the angle that you want, EVEN THOUGH, it's actually off by 1/10th of 1 degree. That's just not enough error to make a difference between a good cut and a bad cut at an octagon corner. There's a misunderstanding in these threads that I participate in, that I use a speed square a great deal. I don't. I rely almost exclusively on a framing square for rafter cutting and other types of angle and bevel work.I've noticed over the years however, how few carpenters carry a framing square to the job site. So, many times, I give answers in speed square angles, rather than settings on a framing square, for other peoples benefit.It's a simple matter to convert one to the other however.Ken
*Pell, blue, others,I really don't feel like going through all the math, but here's the miters and bevels for most common roof pitches. All angles and bevels are rounded off to the nearest 1/4 of a degree.Just copy them out and use them when the situation arises.Ken
*Well that explains it Ken. I was always under that impression that a 5/12 was exactly 22.5. I simply believed it because it was presented to me as fact. I've always presented it as fact, but now will be more careful.Incidently, I usually mark the angles using 10/24. That slight.1 degree does in fact ALWAYS show up. The angles are never precise and I've always wondered why. Now I know.So, what is the exact number that I should hold my sqaure to, if I'm using 24 as one of the numbers, on these octogons?blue
*blue,I'm going to stick with what I said before, and I'm going to explain why.If you want to draw an EXACT 22 1/2º angle using a framing square, you would use 12 on the body with 4.97 on the tongue. Or 4 31/32" on the tongue, instead of 5.I'm sorry blue, but that's just not going to make the difference between a good cut and a bad cut. For a 2x4 plate, the long point would be LESS THAN ONE HUNDRETH of an inch longer using 5, instead of 4.97.If you use 24 on the body, the correct setting on the tongue would be 9.94, or 9 15/16ths, instead of 10. In this case, the long point would be less than 1/50th of an inch longer. It's just not going to make any real difference.I maintain, that if your cuts aren't working, then either the lines aren't snapped out properly, OR, your framing square is SLIGHTLY out of square. It wouldn't take much.Ken
*Ken, maybe you don't notice the difference when you hold 10 vs 9.935, but I do. And I certainly notice that the cuts do not fit. And I don't use framing squares that are out of square. I know how to snap lines. Welcome to a new world...Remember, since I've been holding 10 and 24, the error would be doubled. That makes it a 1/8 gap. Thanks for the new numbers...I'm sure the cuts will now fit!blue
*blue,If you use 24 on the body, you can find the tongue setting, by multiplying the tangent of 22 1/2 degrees by 24. Like thisTan 22.5º = .4142.4142 x 24 = 9.94 ( or about 9 15/16)Now suppose the plates are 2x4. We can set up some simple proportions to see how much difference this would make in the cuts.10/24 = x/3.5x = 1.4583also,9.94/24 = x/3.5x = 1.4496The difference between the two results is .0087", or less than 1/100th of an inch. ( in the long point measurement)If the plates are 2x6 instead, you can use the same logic and find the difference is .0138, which is slightly more than 1/100th of an inch.Granted, this error occurs on BOTH plates, so if we double the 2x6 error, we get2x.0138 = .0276, LESS THAN 1/32"This means that when you put the 2 2x6 plates together at the corner, you will have a very, very,slight gap on the inside corner. Good enough for trim work though.Ken
*blue,I was posting #21 while you were posting #20, so I hadn't read your post before I posted mine.But let me point out an error in your thinking.The difference between 10 and 9.94 is very close to 1/16th of an inch. But that's for 24 inches. Your plates are only 3 1/2" wide or 5 1/2" wide, so the error is considerably smaller, as I pointed out in post#21I'm sure you can snap em out with the best of em blue, that's why I'm suggesting that perhaps your framing square is a bit out of square.Ken
*Ken, my square is square. It's a very simple check, and I check it occasionally.9.94 is not close to 10. It's .06 away. That's alot to me, when I'm trying to get something to fit. I don't deal in generalities when I'm trying to fit something. Either it fits, or it doesn't. On all my octogons, they don't fit. If I don't care that they fit, I simply lap cut and eyeball everything. My eyeball lapcuts fit better than the 5/12 cuts that I mark....ever so accurately...with a sharp pencil....etc. It's always baffled me. Not any more.Incidently, I've often tried to make this cut work for soffit work. The gap is always too wide for my tastes on the 12" ply soffits.blueblue
*blue,It's been fun chatting with you as always. I'm going to catch a little shut eye now, but would like to go a little further with this tomorrow if you have time.Tweet dreamsKen
*blue,Try this little experiment tomorrow, if you get a free moment.On a 2x4, using a very sharp pencil, draw a line as you have in the past, to mark the octagon corner angle, using 10 on the tongue, with 24 on the body of your framing square. This should result in a 22.6º angle.Now, using the same long point, draw a second line, using 9.94, or 9 15/16 on the tongue, with 24 on the body. This should result in a 22.5º angle. A difference of 1/10th of one degree.I think you will find that the 2 lines are so close to each other that there is barely a difference. As I said earlier, the difference at the short point should be less than 1/100th of an inch.This is why I maintain, that if your cuts aren't coming out good at your octagon corners, then there is another reason for it.Ken
*Blue,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Joe...You are informative. So quit the bullshit attacks of Ken or anyone who asks you to be nice like me.Grow up! You act like someone kicked the living shit out of you for your whole childhood. Where the hell are your manners?near tne stream,ajYOu are just as bad as rk. You need to be in the spotlight and you seem to need to rip into anyone else who may have a spotlight on them. Tell me a good joke. Tell me more of flunking out of Brooklyn High. And tell Ken you would like to be nice for a friggin change and work with him instead of rant against him. now wipe your nose little boy and put on some fresh underwear.
*And the blue type...and the logo...and the site that you illegally advertise.It all screams "look at me"Well we look...we laugh...we like your posts for the info...and we like em cause big egos are such fun to fool with! Lets play with fire now little boy...near the whacky stream,ted
*Go ahead and flip out on me...I've had my say and will enjoy your rant.love and kisses,nanuke
*Person with many names. . .,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Thanks for the formula Joe. I don't think it will be helpful for me, because I don't use trig, but at least it's a formula that is available to me, if I want to go to the trouble and learn trig. If I'm feeling inclined, I might investigate a geometric formula. I doubt that I'll pursue it however because I have only worked on these type of cornice work a few times in my career and probably only in commercial applications, which I don't do anymore. If I have to do them onsite, I'd use the old trial and error method and find the true angle on the first or second try. I still don't care what Ken says...I can make perfect 45's work and make a square, but haven't been able to make a perfect octogon work. Now, I now why...blue
*Oh yeah Joe. I agree with AJ!He's not drivelin....he's giving you good advice. Ken does not deserve to be attacked. He stated right away that he didn't want to explain. I'll agree that he also didn't post the formula, as you did, but you could have posted the formula, without adding an insult against Ken. Ken, thanks for attempting to prove that I can't tell the difference because it's only 1/100th or whatever. I'll find out if it matters on the house I'm working on. It has a bay, and I'll know right away if the cuts will finally fit.blue
*You're on it Blue...that little .1 degree discrepancy, times eight cuts could certainly add up to the gap you see when you build octagons.This post reminds me that you should never, ever use the "degree" system and the "x/12" system interchangeably. They are two completely different systems that will never jive, except every 45 degrees. Framers can get away with it because, on many cuts, a couple degrees this way or that way doesn't matter. So we get fooled into thinking that the two systems are interchangeable.
*Blue,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Thomas,There's no question, that if you take a very small error and multiply it by 8, that the error will grow.However, as I understand it, that isn't necessarily blue's problem. What I believe he is saying, is that after he snaps out ANY corner of an octagon, and makes his cuts using 10 on the tongue and 24 on the body, that he gets a gap at EACH corner.He feels at this point, that the reason for this is that he has been incorrectly assuming that 5/12 ( or 10/24), is exactly 22 1/2º. As I pointed out to him, 5/12 is just slightly larger, about 22.6º, or about 1/10th of 1 degree larger.I also pointed out that he can get a 22 1/2º angle by using 9 15/16ths instead of 10 on the tongue, with 24 on the body.Even though this 1/10th of 1 degree will cause a very small error, it won't be enough to create a gap where the plates meet, that will be significant.To demonstrate my point, I'd ask you to perform the same simple experiment that I suggest to blue eyed. devil.Using a framing square, mark a line on a 2x4 using 10 on the tongue with 24 on the body, marking the tongue. Next, using the same long point, mark a second line thru the long point, this time using 9 15/16 on the tongue with 24 on the body.I think that you'll see that the 2 lines are so close to one another, that they practically coincide, and cutting one, or the other, will give you pretty much the same cut. From what I understand, blue is getting about a 1/8" gap, or more, at his corners. This is far more than what will be created, by using 9 15/16 rather than 10, on the tongue.That difference of 1/16th between 9 15/16 and 10 on the tongue of the framing square, sounds like alot. But remember, that's 1/16th in 24 inches, so the error for a piece of wall plate, only 3 1/2" or 5 1/2" wide, will be significantly smaller.Ken
*Mr look at me....or should I call you Usama Bin Ladin....Tolerance is the key to life. Certainly we all show it of you...And blue! Blue...you know what I'm talking about you libertarian!So how about forgiving whatever mis-steps anyone has had with you Joe. I certainly believe in tolerance...and humor...just don't memorize jokes very well!Blue...we need a joke....Love and kisses to all,GeorgeOff ta work I go...hi ho...hi ho...
*Person of many names,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Thanks Ken. I might have misunderstood where Blue was getting gaps.By the way, your reply could have ended after the second paragraph.
*Thomas,Thanks for posting that. I'm sorry if I beat that to death. My apologies.Ken
*Joe...this is your millionth attack post.Just thought I would drivel that fact to you.near the stream,Joe
*
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Person of many names,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*All of this content is useless....i Dyslexia Sucks! ICQ:41132556 ICQ Activelists: 50218085, AIM:fvcon123i 12 and counting and that's a fact. i "The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it."i Aristotle BORING!!!!!!!!!!!!!!!!!!!Sharing drivel near the stream,BOO!
*Person of many names,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Thank God you know how to find quotes to post...as your thoughts seem to be very limited yes!?near the empty stream fishing amongst the rocks,aj
*Person of many names,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*This will make you say mom upside down. WOW
*Wait just a cottin pickin' minute there Joe. I did say thanks, and was genuine about it. And I didn't offer any opinion. I waited a post to offer that opinion....that doesn't count against me, so there!You can call him Ken. It sounds a lot less passive aggressive.Ken passed on offering the explanation, and instead gave a chart that give the answers. I'm thanful for that, because I know that anything that you, Ken, or anyone offers here is a gift. I truly appreciate the gifts that I've received from this site.I did want that formula too. I wanted it to see if it was simple enough for me to pursue the understanding of it. Remember, I never really learned trig (I skipped out permanantly after one week in high school). I only use geometry and your equation was over my head and I just don't want to invest any more time in that particular aspect of the trade. Like I said, I might attempt to construct a geometrical equation, but probalby will not.Anyways, if you want to take me to task for jumping on AJ's bandwagon, you'll have to admit that I made a pure and simple thanks, without the negative comment attached to it. Check the time...I waited at least a minute...blue
*Ken, I'm not saying that I always have an 1/8" gap. I am saying that the cuts NEVER fit. I know the difference between an exact fit, and a fit that is not exact. My cuts have NEVER fit exact, and I've always wondered about it. I will be cutting the plates on the bay, in the next day or so. I'll let you in on my results. I'm going to use 9 15/16 and 2 and anticipate a perfect fit!blue
*Right AJ! Joe, don't post all those other guys sayings. Post your own.I've got a few...I'll try to remember them. It getting hard because I'm old and over the hill...blue
*Thanks Ken and Joe I do appreciate the info,with Kens table and Joes formula I can check my math out as I am not a mathmatician but do need to use trig.Thanks again and I even know quite a bit more about circular railings now.lol
*Holy Cow i figured it out and it makes sense.Except for the hip face cut its the same cuts as a hip roof but for the "counter pitch" of the roof pitch used.For a i2/12 roof the counter pitch is 12/12, for a 4/12 it's a 36/12(4/12=18.43',36/12=71.56' the complimentary angle of 18.43')The face fascia angle is the same as plywood would be cut on that hip,the fascia bevel and hip bevel the same as that hip's backing bevel. The hip face bevel is the counter hip pitch degrees (36/16.97) plus the roof pitch hip pitch degrees(4/16.97) subtracted from 90 degrees(the left over degrees on the square hip end) or 64.76' plus 13.26'=78.02'.That leaves 11.97 degrees to be cut off of 90 degrees.So starting with the common roof pitch, get the "counterpitch" and work it out like a hip.This is for regular 45 degree hip roofs.Of course i could just get " the roof framers bible" and not risk screwing up but it is interesting to "get it".In 27 years i can remember one roof with square rafter tails and we did it the just do it way. We scribed and eyeballed it.Anyway does this make sense ?Will Holladay in his book A Roof Cutters Secrets uses the rise of the roof pitch and the line length of that pitch in 12" on the square,the rise side of the square being the fascia face cut. For the bevel cut of the fascia and hip he uses the line length in 12" and the unit run 12", the unit run side giving the bevel.For the fascia face cut i got the same answer but not for the hip/fascia bevel.Anyway since the counter pitch method makes sense to me ,i'll remember it as opposed to an abstract formula or equation.Abstract to me.I tried Joe's equations but i think im pushing things wrong or in the wrong order on my calculator because i cant come up with the right answers.It is interesting to figure this all out without a calculator with a pencil and square and drawing.Dang look what time it is."Counter pitch" is a term H. Siegle (i think thats his name)may have used in his book on roof framing, when rafters were "stepped off".
*boyd,Good analysis boyd. That's about all there is to it.Those are pretty much exactly the same ideas that I used in solving the equations.Once I wrote the equations, I put them in a chart, for easy use by others. ( Post #17 )The key idea here, as you said, it that the fascia can be considered as the sheathing of a roof, that has the counterpitch of the roof you're framing. So if you determine the "plywood cut" for the counterpitch roof, you are finding the fascia face angle, or fascia miter.In Pell's example, 5/12 pitch, the counterpitch is simply the pitch of the roof "turned upside down", or "inverted". So the counterpitch of 5/12 is 12/5.If we set up a simple proportion,12/5 = x/12, we find x = 28.8. So the counterpitch for 5/12, is 28.8/12. The "plywood cut" at the hip corner for this counterpitch roof, using a speed square, is 21º. So that's the face angle for the fascia.The circular saw BEVEL, to cut both the hip and the fascia, is the same as the backing bevel for the hip of the 28.8/12 roof, which would be 40 3/4º. There are a variety of formulas to calculate this bevel. The one that Joe shows in post#26 will work fime.The face angle on the hip, as boyd mentioned, is the result of adding the roof angle of the hip, to the roof angle of the counterpitch hip, then subtracting the result from 90º.The pitch of the 5/12 hip = 5/ 16.97 or 16.417ºThe pitch of the 28.8/12 hip = 28.8/16.97 or 59.492º16.417º + 59.492º = 75.9, or very close to 76ºTherefore, the speed square angle, for the face angle on the hip, is 90º - 76º = 14ºboyd, I'd like to add that, in my opinion, and as you suspected as well, not all of the formulas that Mr. Holladay shows in his book, "A Roof Cutter's Secrets" are correct. Your ideas, and the ones I've shown here, I believe are.Once again boyd, nice analysis.Ken
*In my post #17, I provided a chart for making the various cuts on the hips and the fascia, for most common roof pitches. The angles are measured using a speed square, and of course, the bevels, are the circular saw tilt angles.For those of you that would like a fairly simple formula to make this calculation for the face angle on the hip, at 90º corners, look at the diagram that I've posted below.In a 5/12 pitch roof, 5" is the "unit rise" and 12", as always, is the "unit run". The "unit rafter length", is exactly 13". 5,12,13 is a perfect right triangle, just as the familiar 3,4,5 right triangle is.Now, if you divide the unit rise by the unit rafter length, you get 5/13 (see diagram)Also, the unit run divided by the unit rafter length is 12/13.Now, multiply the 2 fractions and then multiply by .7071,.7071 x 5/13 x 12/13 = .2510Finally, find the angle that has .2510 as it's tangent. That's the face angle , or miter angle, on the hip.Tan-1(.2510) = 14ºFor those of you that are comfortable with trigonometry, an equivalent formula would beFace angle= Tan-1(.7071(sin roof angle)(cos roof angle))BTW, .7071 is simply the value of the cosine of 45º, in case you were wondering about this "mystery number"
*Notice that the formula and methods that I showed in my post#55 apply to regular hips at a 90º corner. It's possible , of course, to work out the mathematics for this face angle cut for other regular polygons also. ( hexagons, octagons, etc..) Suppose that P = the Plate angle, which would be 1/2 of the total corner angle. For example, for an octagon, there are 135º in each corner. So P = 1/2( 135º ) = 67 1/2º Also, Suppose that R = the Roof angle, which is just the pitch of the roof expressed in degrees. You can find the face angle on the hip, using the following formula, Face Angle= Tan-1(((cos²P)(sinR)(cosR))/sinP) Most carpenters don't find these somewhat complicated mathematical formulas very usefull, which is exactly why you seldom see me posting information like this. But there it is anyway, just in case anyone is interested. Ken
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Joe,You've got 8 left parenthesis and only 7 right ones.Fix it up so that your formula is clear, and I'll take another look. Ken
*bravo this...who made you king shit.near the stream,aj
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Maroon....!>?....somewhere between red and purple!>?near the moron apparently,aj
*Joe,No, actually I worked those out about 7 years ago for your information.Now, is your "all around formula" good for all plate angles, or just for 90º corners?
*Earth to Joe....Earth to Joe.....
*Joe,Obviously my question sent you into the tank.Do you need help?
*Joe,I asked you a simple little question. Try not to make a career out of answering it.
*Joe,It's not that difficult Joe. If you need help, just ask.
*Joe,Maybe you should look in the Roof Framer's Bible
*Joe,Maybe an AutoCad Sketch in 22 colors would help?
*Joe,Here's something else for you to think about.You know that public apology that you want me to make to you?You can expect it at about the same time that George Bush receives a dozen long stem roses and a box of Ghiradelli Chocolates from Osama bin Laden. Ken
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Person of many names,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*That's it...yaa fell on your head as yaa flunked outa high school...or was it elementary school?Anyway...a little blood dripped out...somebody said the blood looked maroon and you thoughts they wuz callin yuz a moron! And the kid saying it was a math wiz too...so now yaa get all full chested and beat on math wiz's on the internet!That's my drivel for today buddy...near the stream,aj
*Person with many names,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Joe,Yeah right. You were watching a movie, and I was playing GO FISH.That's been your pattern in the past Joe. When you have something to say, you post your brains out. But when you can't answer a question, you run and hide under the covers.So let me answer the question for you.I asked you if your "all around formula", that you stated in post#58 was good for all plate angles, or just at 90º corners. Here's your "all around formula"Hip miter = Tan-1((((sin (roof angle))*(cos (roof angle))) * cos(joint angle/2)))!The answer is NO. It's only good for 90º corners. Therefore, Joe, in the formula, cos(joint angle)/2),will always be equal to cos 45º, or .7071. In other words, it remains CONSTANT, so you might just as well express it that way, and write the formula at 90º corners as,Tan-1((.7071(sin roof angle)(cos roof angle)) EXACTLY THE WAY I ALREADY SHOWED IT in my post #55. Now, doesn't that look a lot more user friendly to you, compared to your "all around"?For plate angles other than 90º, I took the time to show the formula in my post #57. Here it is again,Face Angle=Tan-1(((cos²P)(sinR)(cosR))/sinP),where P is the total plate angle, and R is the roof angle.You claim in your post #58 that the cos² in my formula makes you dizzy. You're a pretty dizzy kind of guy anyway Joe, so I'm sure it really doesn't bother youi that much.But to unwind your head, here's an equivalent version of the same formula,Face Angle= Tan-1((cotP)(cosP)(sinR)(cosR))In the future, feel free to call on me when you need help answering a question.I'll be here for youKen
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*What is happening to this board?I am grateful to anyone that can help me learn. There is a ton of wonderful information in here. But I am getting tired of wading through all of the shit to get to it.Grow up assholes.
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Joe,Go ahead and order a copy of the Roof Framer's Bible.Your not going to see any of my work in there though.As a matter of fact Joe, that book contains several small errors in the hip and fascia bevels, which he incorrectly refers to as the "miter".In his charts, he rounds off the bevels to the nearest degree, but in two cases, his results are incorrect.For a 4/12 pitch roof at a 90º corner, the correct bevel is 42º, not 43º as he shows.Also, for a 6/12 pitch, the correct bevel is 39º, not 40º, as he shows. It might interest you to know Joe, that I've never used this book for any purpose whatsoever other than seeing what is available to the reading public.As I've mentioned to you before, I had worked out all of the formulas in his book, as well as many others that don't occur in it, several years prior to even knowing that the book existed.Unlike you, Joe, there are some of us out there, that have had a good handle on this knowledge for a long time. You're a newbie to this knowledge, but you don't know it.Ken
*I'm out of here for a while Joe.Stop asking me to do this or that. I've already posted my information. YOU go do the calculations if you're so interested.Or do you have another movie that you have to watch?
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Joe,No Joe, I'm not done. You may be done however. In fact, you may be overdone. How's the Wednesday afternoon movie today BTW?
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Joe,Since I'm leaving for a short camping trip in the morning, I'm going to honor your previous request, and examine the results of our 2 formulas.Let's take the same roof pitch that Pell was using at a 90º corner, 5/12, and see what our formulas predict the hip miter to be for a regular octagon.For the sake of simplicity, let's letP = the Plate angle, or what you call 1/2 the joint angle. The angle that the hip makes with the plate, in plan view. For an octagon, each corner has 135º, so the Plate angle = 67 1/2º, andR = the Roof angle, which for a 5/12 pitch, = 22.62ºI've already shown in a previous post, that,sinR = unit rise/unit rafter length = 5/13, andcosR = unit run/unit rafter length = 12/13Now Joe, your "all around formula" says we can find the hip miter by using,Hip miter= Tan-1((sinR)(cosR)(cosP))Hip miter= Tan-1((5/13)(12/13)(cos67.5º))Hip miter= Tan-1(.1359) = 7 3/4ºI say the correct formula is,Hip miter= Tan-1((cos²P)(sinR)(cosR)/sinP)But since the cos² makes you dizzy, I'll use an equivalent form,Hip miter= Tan-1((cotP)(cosP)(sinR)(cosR))Hip miter= Tan-1((cot67.5º)(cos(67.5º)(5/13)(12/13))Tan-1(.0563) = 3 1/4ºSo whose formula is correct? Mine our yours?Ticky Tocky..Ticky Tocky.....Ken
*Joe,Helloooooo....Ticky Tocky...Ticky Tocky
*Joe,Don't tell me you're watching another movie.I ain't buying it....
*Joe,I'm leaving for my camping trip i tommorowmorning.
*Joe,I see that you're in the tank again.Tell you what. I'm going to load some firewood and camping supplies in the van, and I'll come back and check on your progress in about 30 minutes.And Joe, you can't come along on my camping trip to discuss this over some roasted marshmallows, so answer the question today please.Ken
*Joe,Hurry up. At 4p.m.Eastern, HBO has Greystoke:The Legend of Tarzan, Lord of the Apes, and I know you don't want to miss it.Ken
*Would you like me to repeat the question?
*Joe,If I knew that one simple question could shut you up for so long, I would have asked it about 3 years ago.I'm going to the store to get some provisions for the camping trip. Do you want me to get the big marshmallows or the medium size ones? I like to burn mine around the edges just a little bit. You know, let them catch on fire, then quick blow them out. How about you?Bring your own stick.Ken
*Joe,It's been almost 3 hours. What are you doing, making a model out in your shop or something?I got the marshmallows. I also picked up a couple of baking potatoes, chips and dip, soda, and corn on the cob. We can wrap the corn and the potatoes in aluminum foil and throw them in the fire to cook.Would you mind stopping by the store on the way over and picking up a couple of nice New York Strip steaks and a couple of bottles of good French Cabernet Franc? Maybe a case of Heinekin too, come to think of it.Ken
*Mr. Drake,
View Image"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Joe,Yes, I knew all along that your formula was only good for 90º corners. As I said before Joe, I worked out these formulas about 7 years ago, so there really wasn't anything much new for me in this thread. (Except for someone calling me a Maroon, whatever that is)I really like the formula that I showed you. Tan-1((cotP)(cosP)(sinR)(cosR))for the hip miter. The derivation was fairly easy, and interesting. I i mayshow it sometime Notice what happens at a 90ºcorner. P, the Plate angle = 45º, so the above formula, which works fori anycorner angle, reduces toTan-1((cot45º)(cos45º)(sinR)(cosR)),or,Tan-1((.7071(sinR)(cosR))which is essentially your formula in simpler form. That's the best form to use that formula in for 90º corners, as I suggested in an earlier post.It's been an interesting thread. Strangely enough, I've actually enjoyed it, even though you can be a real bitch sometimes. But I understand.Don't forget the Cabernet Franc.Ken
*Joe, I think Ken gave you another spanking. blue
*Ken: I have never seen anyone so thorough and so sure of himself in his math as you. You backup and prove everything you put out. I respect that.
*God damn it , me and my jack ass got left in the dust but dang if they didn't leave a trail.The droolers at the back of the class even woke up.Now thats the way to teach.What's interesting ( but baffeling) to me is how reduced or shortened the trig formulas can get in comparison to what i have to go through to get the same answers. Speaking for myself i have to say how helpfull it is to along with the formulas have actual stepped out examples.I'm sorry to say i didn't take high school trig, no but i did take hallucinajins . Didn't make it to the spelling bee either. Come on e-or wur hot on the trell.( i believe Maroons were a group of runaway ( previosly slaved) people in Jamaica that escaped to the mountains where the British got there tails wooped every time they tried to go after them.A tuff bunch not to be messed with. It's a compliment to be called that.
*boyd...great post....and welcome to the Maroon Club as secretary...One Maroon near a stream,aj
*I gotta agree with ya' AJ. I'm beginnin' to like ole' Boyd, even if he is too chicken to wager with this ol' yankee boy.Boyd, I bought me a new Makita today. I'll snap a few pics of it tomorrow and show yall anchor toters how us yankess cut them plates with it...blueps you owe me a few milkbones jest fer chickenin out!
*Blue, All i have is chicken bones .Thats what they call me at work also. Sea anchor is also the name given to my worm drive by these same sidewinder boys.When you bet me on the door plate cutting i ran out in my barefeet to the shed to try it with my worm drive. I cut it square against the table first then set the saw ona 45 bevel , titled it up and cut it at the jack . It was 3/8 short of cutting through. If i had an 8 1/4 worm drive i thought it might get it and sent back a bet to you that a "worm" could do it. You didn't say what size saw so i made the counter bet. I really don't know though and it was sort of a bluff. If the 8 1/4 didn't get it, it was on to the 10' Bigfoot conversion. That ain't an anchor , thats an outboard! Chickenlegs
*Don't fret boyd, I'll take chicken bones on a suckers', oops I mean honest bet. I aint takin any chicken bones on the nail balancing bet though.Also, don't lose any sleep over leaving 3/8" on the door plates. Jest git out yore pocket knife and set to carving. I'm sure you'll have them all cleaned out by the time the carpet goes in....If'n I see you coming up the drive with the 10' bigfoot, I'm getting the hell back to yankeeville! blueSorry I couldn't take pics today. I tried. The batteries were dead as a door nail. Are door nails real dead?
*Sorry about the batteries. Did the octagon cuts fit?
*Sorry Roger, when it came time to do the bay, I opted out and had an employee do it. I'm so bored with framing these houses that I'm now constantly searching for the easiest job of the moment. I also use a much faster method of cutting the plates and don't actually use any tools other than my saw. I don't even use a pencil. It's fast and the cuts always fit! I have used the framing square in my earlier days of bay framing and I also use it when I'm making a complete octogon.I was ready though with batteries and disks. blue
*
I am cutting a hip roof with square cut rafter tails(not plumb cut).Is there a way to figure the miter and bevel angles for the hip and the subfacia? Id rather not make a mock up to figure it out.It seems simple, ya right.Any help would be appreciated.Thank you in advance.
Pell