Framing Square Pro Tips

okay so let's talk a little bit about the tools that are used for cutting rafters cutting the pitch on rafters but before we start that the difference between a rafter and a joist joist is always level whether it's a floor joist holding a floor diaphragm that's level or a ceiling joist that happens on top of the wall and defines the ceiling of a roof system the joyce's level the rafter is sloped okay this is a mistake people make sometimes they call it roof joist ceiling rafters this is backwards a joist is level of rafters pitched this is a speed square very handy tool this is a framing square people call it a carpenter square or a steel square the framing square is a profoundly underappreciated tool and frankly you have to have a little education to be able to use it you also can't carry it with you all the time I mean there's no way to carry this and climb around and be agile this is meant to use on the ground at ab and Jetta set of software system this is an adaptation of some of the critical aspects of this tool it can be carried in your bag use just as a simple square or subscribe or as a gauge but primarily people think of it as a way to put the pitch on a roof this is a 312 roof pitch and here is how a framing square identifies that pitch on the short leg you put the three flush with the edge of the board on the long leg you put the 12 flush with the edge of the board and that describes a 3 12 pitch 3 inches of rise 12 inches of run now let me show you how that works with the speed square you put the pivot of the speed square on an edge of the board and then you rotate the speed Square and read the pitch designated a number of inches of rise per 12 inches of run bring it down and tell the 3 is flush with the edge of the board you will know that this leg of this right triangle is plumb or vertical so this is called the speed square for good reason and probably 80% of the people that own these use them for making square lines a hundred percent of the time they're fast it's like this full square that's a speed square now they alternative of course if you have the framing square is nearly as fast a little less certain square line but you just can't beat this speed also comes in equation establishing the rook pitch as we just demonstrated it's fast to throw that down on the board at the pivot swivel to the mark and mark contrast that with the framing square you have to deliberately set the mark on one edge deliberately set the mark on the other edge capture them and see it moved captured a speed square is pretty handy but it will not do the things that this will do let me show you how these rapper table people are I go in sick corpse me I'm inside eat it no one near that square PA well so on a real framing square there will be rafter tables and as you can read there are six different tables on this side of the square as an example length of common rafter four foot of run on this little building it's a three 12 pitch and it's 8 feet wide but the run is the amount of horizontal distance that an individual rafter is spanning so for one of these rafters the run is 4 feet minus half of the thickness of the ridge so you would calculate that that's 3 feet 11 and a quarter inches you would put that in a decimal equivalent and then you would come down this scale to the number value that is right directly below the 3 because the 3 signifies 3 12 pitch on a 3 12 pitch the length of the rafter per foot of horizontal distance is 12 point three seven inches where are we 12 point three seven is the distance on this rafter on what is the hypotenuse of this triangle it's twelve point three seven inches from here to here those values are all given on this set of numbers on this wonderfully versatile tool and can be used to calculate the rafter length without measuring anything in the structure but rather just working off a set of plants in addition to the tables that give length of common rafters per foot of run for each of the roof pitches length of hip or Valley rafters per foot of run for each of the roof pitches we have a table that gives difference in length of Jack's that is the intermediate rafters that go from the ridge to the hip or the ridge to the valley let me say that again from the plate to the hip or the ridge to the valley on 16 inch centers or 24 inch centers we also have tables that give us the sidecut of those jacks which is not necessarily 45 degrees so this will give us the sidecut and it will also give us the sidecut of hip or valley Jack's handy if you're a roof cutter you've got to be able to use that so this table is a brace table so this is an example of a knee brace it's not a great example but you see that this 2x4 is located in the hypotenuse of this triangle and the breaks table on a framing square describes the length of that brace or that hypotenuse for instance if we were going to come down 24 inches by 24 inches on the leg of a triangle then the knee brace or the hypotenuse of the triangle would be thirty three point nine four inches long if the brace was going to originate 48 inches from the 90 and die 48 inches from the 90 then the hypotenuse of the triangle or the brace would be 67 point eight eight inches long this is a brace table that ranges from 24 by 24 to 60 by 60 and I expect that that is a 30-60-90 triangle this table is a sort of multiplication table many of the tables in fact most of the applications of this square for cutting roofs have been obviated by construction master calculators and by the rafter table book that roof cutters carry around with them it's still good to know how to use this but this gives you the length of two times 8 equals 1 foot 4 which is 16 inches 2 times 9 equals one foot 6 which is 18 inches 2 times 10 equals one foot 8 which is 20 inches 2 times 11 is one foot 10 which is 22 inches etc that becomes useful if you have larger numbers for instance we know being consistent that 16 times 8 is 10 foot 8 16 times 9 is 12 feet 16 times 10 is 13 feet for all of these numbers became a calculator for the carpenters who were calculating the hypotenuse of triangles and common rafters and hips and valleys who were doing the math without the benefit of a calculator and didn't have time to do everything longhand every time but could have if they needed to but here's an interesting characteristic that a lot of people never notice that on this square this scale is divided into inches and tenths of an inch this scale is divided into inches and 12th of an inch you'll notice it in between what are the quarter-inch gradations is divided into three pieces not four and this scale also is divided into twelve while this scale is divided into the customary sixteenths of an inch that we're used to seeing on metal tapes that would help a carpenter as he was converting the rafter tables into hence 12 hundredths it was important for him to have these different references in his length in making his calculations quickly some squares and I'll show you one here in a minute even have a little table on there which tries to give you hundredths of an inch in a one inch segment so that you could at least estimate your decimals back over to fractions so let's do a quick comparison of two squares that were probably made a hundred years apart this square belonged to my grandfather was given to my dad soon after he was married has all of the same scales and capacities that this modern square I bought this at a clearance sale some time oh four or five years ago they're good squares this was made by Stanley this one is made by nickels which was a very well-regarded manufacturer of measuring instruments raster tables breaks tables this does not have the multiplication aid but instead it has a detailed explanation of using the raster tales tables to calculate rafter lengths and jack lengths I'm not going to read that to you you can get that out of any Raptor framing book figure it out or revisit as part of the conversation you had in this video it's not hard but you have to know how to do it interesting that they would print the directions on a square 100 years ago there are a couple of obvious obvious means as I hold these differences between these squares this is made of steel this is made of aluminum I like the aluminum square doesn't weigh much but there are reasons that a steel square could be more desirable steel square stuff it's hard to bend if it doesn't get bent I'll show you how to fix it an aluminum square bends easily doesn't weigh much the numbers are nicely contrasted with a black sort of an agonized finish and a yellow paint down in the bottom of the numbers you can read it rust will disfigure you can see I've polished the stuff I should have done it years ago makes it hard to read the tables when they get rusty in the Sun if you've ever worked in the American Southwest I've worked in Las Vegas a steel square in the Sun will lifter your hand an aluminum square axon is hot but does not hold as much heat and will not give you the same kind of a burn here's how you test your square put it against the edge of a nice straight piece scribe a line flip your square over try to stay out of the shadow describe another line this square is not square and you see that we have about a sixteenth of an inch of gap we have a quarter of an inch of gap this square is about an eighth of an inch too far open we draw a line from the inside corner to the outside of town in order to close this square back to 90 degrees we have to stretch the metal at the outside of the corner we're going to do that with a center punch and a hammer on an anvil I'm going to take this Center punch and I'm going to put about three marks all on the outside of the center of this line which is going to stretch the steel on that side which will bring this square back to 90 degrees I'll come right out about the quarter of an inch back from the corner and set I'll come back about an eighth of an inch and set I'll come back another eighth of an inch said it let's check it and see what we've done and we know that these two lines were square with each other using a square that was in fact 90 degrees we're going to verify against those lines and see how we've done hurry that's how you tune a square I've got to confess some ignorance I have no idea what this table is for these appeared to be 1 2 3 4 fifths of an inch but they're not you see we're lined up with the two but if you come out to 14 which would be 12 inches down the line we do not line up with what should be the 12 inch distance so these are all a little more than one inch apart divided into five increments I have no idea what it's for well somebody out there who knows more about this game than I do please respond and let me know what in the world that table is for on my framing square appreciated you

Channel: Essential Craftsman

Views: 999,705

Keywords: Square, Speed Square, Framing, Carpenter, Carpentry

Id: V1S4ZVHDc9A

Length: 15min 2sec (902 seconds)

Published: Sun Jan 29 2017