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Ok carpenters, I know how to use all the graphs on a framing square but one. If you are holding the square in front of you with the short lag to your right and down, there is a graph down the middle. 5,10,15,20,25,…, with four marks between each number. WHAT IS THIS GRAPH FOR??. I do know it is not angle degrees.
Thanks So much
Charlie
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Replies
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sounds like the diagonal scale for determining the 100th's of an inch....
b but hey....
*Thanks MikeI thought of that but it's not.Thanks very much for your input.Charlie
*Charles,
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*Hay thanks JosephHow does it work????Charlie
*Charlie,I believe it is called the "Eight Square Scale". In conjunction with a pair of dividers you would use it to lay out the profile of an octagon on the end of a square timber. Not that I have done that recently, like since before 1980 when I bought the Craftsman square that came with a little booklet describing this procedure. If I had a scanner, I'd post the graphic in the book. Doesn't seem to be much else you would use this scale for unless one of the local layout wizards here on breaktime has another idea.
*Hi Charles Morrison,The table on the face side of the tongue is the Octagon Table.The dots indicate equal spaces with with every fifth space numbered, as 5, 10, 15, and so on.Its used to make an octagon from a square. A compass is used along with the square to locate and snipe a square's corners.That's para phrased from "Roof Framing" by H.H. SiegeleThe Diagonal Table appears on many squares and also uses a compass in measuring.
*Charles...You are Orlo's buddy, right ?b : )Probably Louis as well.
*Dan-O, is Siegel's book still in print?
*Hi jcallahan,To my knowledge, "Roof Framing" by H.H. Segele is still in print. The copy I've got was published in 1982 by Sterling Publishing Co., N.Y.(orig.1947)The preface says, "This volume has been prepared so that every carpenter, and particularly every carpenter apprentice, will have available a book that gives in a practical way the fundamental things about roof framing..."Its boiler plate stuff. Two thumbs up!
*Sorry I do not know those fine people
*Thank You very much Dan O.Charlie
*Charles, The scale you're wondering about is called the octagon scale. It can be used to lay out octagons up to 67 inches wide. To use the scale, you start by laying out a square. If, for instance, you should want to lay out a 38-inch rough opening for a 36-inch octagonal window, you begin by carefully framing a square 38-inch opening in the standard manner. Next find the center of each side of the square opening. From each center point, measure out in both directions a distance that is precisely equal to the distance from the zero point of the scale to the third dot after 3/5 (which represents 38 on the scale). That distance is about 7 7/8 in. Marking those eight points marks the eight corners of the octagon and all that remains is to cut and install the four angled pieces to frame the octagon. Each piece would be double the distance on the octagon scale or about 15 3/4 in. long.The reason for the dots? In the days before WWII, many carpenters used dividers to transfer small measurements. The dots are small dimples into which the carpenter can insert the points of the divider, making it easy to set the divider to the desired length.The editors of FHB have in their possession a two-page article on this very topic (written by me) with drawings and, maybe, a photograph. They are just waiting for a good place to fit it into the magazine. Hopefully, it'll appear sometime this year. Also, I discuss using the octagonal scale on pages 50 and 51 of my book, "Measuring, Marking & Layout." In the same chapter, I also discuss how I lay out octagons larger than 67 inches, such as the foundation for a gazebo.
*John,
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*John:I can not thank you enough for this level of information. I teach a 8000 hour four year Journeymen / Apprenticeship Carpenter Course for the Associated General Contractor of America, Oregon - Columbia Chapter in Portland Oregon to men and women that work more than 40 hours per week in the industry and then put in an additional four hours per week in one of my classes. The materials we use are from the National Center for Construction Education and Research (NCCER). I find them to be quick lacking, for such a common tool. I was to the point that for my classes I was going to write up a complete guide on the use of a Framing / Carpenter Square. In all my time in the construction business, since 1967 working as an architect and as a commercial general contractor, I have never had the opportunity to use that graph on the square. I use a computer aided design drafting software called AutoCAD since 1981 when I needed to do some really off the wall stuff.How can I get your book for use as a reference for my classes? and what can I do to push on FHB to run your article, I am sure if I am looking for this information, there is a lot of others out there that would want the same info. Here is a good one and I have the answer even though it took me a weekend thinking on it. One of my students asked me that we use a 45 degree angle often, and 22.5 as half that. On the square for the 45 as you know we would call out 12,12. Then he asked why can we not use 6,12 to get 22.5 degrees?Thanks AgainCharlie Morrison
*Charles,The reason that the degree equivalent of 12/12 is not twice 6/12 is because the curve representing the angle of pitch (if you were to graph the angle on an "x,y" graph) is not linear. It's not a straight line. It also asymptotic, meaning that one can never reach the 0 or 90 degree points on the graph. In other words, one can never reach horizontal line if there is any number other than zero on the numerator of the pitch symbol. Or, one also can never reach plumb by increasing the numerator. If 12/12=45 degrees, then 24/12 is 90 degrees? Of course that's not the case. 24/12=63.4 degrees. Maybe Joe can post some graphics to explain this better, but I will admit that I was also wondering about this one for a while a few years back.Jon
*Thanks again JonYes I got the same answer, and went as far as CADDing up a graphic to show the students why. I just tried to send a graphic on another question by someone else, but my graphic never came over. Once I can find out how I might use "Attachments:" to post my graphic along with my posting, I will put it up for all you guys to see.Does anyone know if chat program will allow for TIF files, I saw another guy post a GIF file along with his posting.Charlie
*charles..easiest way for me to get graphics into this site is to export a .bmp or .dxf to a file.. then convert it with a photo shop type program ( i use ThumbsPlus4 or IrfanView ) into a .jpghere's IrfanView (it's freeware)...http://www.irfanview.com/english.htm.jpg 's post easy here, and most will not have any trouble opening them.tifs do not open for a lot of people here..
*Joe, Your web site is simply awesome. I have learned much from your comments on this forum and from your web site.Charles, Both of my books, "Measuring, Marking & Layout" and "Working Alone", are published by Taunton and can be purchased from their online book store. Not to get greedy but, if you decide to buy them in quantity for your classes, you can get volume discounts at Taunton (please forgive the pun). They are also available at most Home Depots; they are in a rack near the pro checkout counter. You can also get them at amazon.com or barnesandnoble.com. I hope this doesn't sound too much like a commercial but you did ask where you could find it.To help expedite the appearance of my article, you might send an e-mail to Andy Engel, who referees this site and is also the senior editor of FHB.Concerning your student's question, I would simply say that degrees and roof pitch are two separate and largely incompatible ways to describe angles. They developed independent of each other, not unlike two languages. About 3000 years ago, the Sumerians divided the circle into 360 degrees. No one knows for sure why they did this. It could be because it takes a little over 360 days for the earth to circle the sun. This number is evenly divisible by 12, the number of times (approximately) that the moon goes around the earth in the same period. The division of the circle into 360, however, is not divinely decreed. But for the Sumerians, we might have had a circle divided into 100, 200 or, perhaps, 400 degrees. As it turns out, though, we're stuck with a 360-degree circle.This 360-degree circle has very little to do with roof pitch, which is a simple description of the relation of rise to run. However, both degrees and pitch can be used to describe the exact same angle. We can "translate" pitch into degrees and vice versa but a simple approportionment of a unit of pitch to a degree of angle does not exist. Such a translation requires trigonometry.Joe and Charles, It is nice to meet you in this forum. I am honored by your kind words regarding my book.
*roof framing by a man named gross first name escapes me was sold by craftsman publication's this was god send when we started out. this just supports my belief in a proper apprenticeship program. this still help's at 9pm until ? and after 23 yrs. the pages are dog earred
*Ok let us see if I can get the graphic to attach.Charlie Morrison
*Mike SmithThank You very much on the tip to use .jpg files. I am new to this site and the first time around I tried to send a .gif file.I used Photoshop 6 to convert my AutoCAD drawing. I saved the drawing as a image file (.tif) opened it in Photoshop and resaved it as a .jpg.Thanks Again.Charlie
*Another way to look at the Degrees relative to pitch thing is like this:A 1/12 pitch is 4.8 degrees, or an increase of 4.8 degrees above a horizontal line. (Or zero degrees)A 2/12 pitch is 9.5 degrees - an increase of 4.7 degrees over 1/12A 3/12 pitch is 14.0 degrees - an increase of 4.5 degrees over 2/12A 4/12 pitch is 18.4 degrees - an increase of 4.4 degrees over 3/12A 5/12 pitch is 22.6 degrees - an increase of 4.2 degrees over 4/12A 6/12 pitch is 26.6. degrees - an increase of 4.0 degrees over 5/12It's sort of like the law of diminishing returns, I guess. The number keeps going down. The difference between 11/12 and 12/12 is only 2.5 degrees. This concept is hard for everybody to grasp right away. Every truss designer I've trained has struggled with it. Don't feel bad if you don't catch on right away.
*BossThanks for the info.CharliePS. Check the attachment I left down below this posting under my name.
*Charles, Another way to show your students the reason a 6-in-12 pitch isn't a 22 1/2 degree angle is to make a drawing superimposing a triangle representing pitch on a circle with degrees. I've attached a drawing to show what I mean. The circle in the drawing doesn't have degrees on it and the triangle is a 7/12 but I think you'll see what I'm trying to show. This is my first attempt at posting a drawing so I'm not sure the darn thing will even post.
*Here are two drawings that show how to use the octagon scale to lay out a 49-inch octagon.
*And
*John CarrollThank you for this outstanding information, the drawings tell the whole store.PROBLEM: the pitch block and circle.jpg will not load. The other two, Oct Scale A & B jpg did load and look great.let me know if I ever can be of any help to repay for this information.
*John,
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Ok carpenters, I know how to use all the graphs on a framing square but one. If you are holding the square in front of you with the short lag to your right and down, there is a graph down the middle. 5,10,15,20,25,..., with four marks between each number. WHAT IS THIS GRAPH FOR??. I do know it is not angle degrees.
Thanks So much
Charlie