Speed square basics - How to use one

haymakers this is Mayfield modify I'm Justin and today we're going to talk about speed squares because it's so fast alright so here's a trick for using a plumb bob and a speed squared for finding a level line instead of a plumb line so first you take your plumb bob I've got to screw up here and you hang it to get a plumb line take your speed square and use your pivot point and we're going to mark low try not to disturb your line pivot point and you go right through 45 degrees and you draw your lines those are level lines and we'll check it yep between the lines level with plumb has speed squared okay so this is a really good trick when you all you have is a plumb bob and a speed squared you need to find the pitch of a roof so this piece of wood represents at the outside rafter of a home and I put a screw inside of the wrapper and I'm just hanging the plumb bob there to give myself a plumb line and then you just take your speed square and you slide it up you take the seven-inch ruled side of the square put on the underside of the rafter and you slide down to meet the pivot point so your line crosses through that and you can see that through the pivot and down through the common line delineations it's on seven that means this roof is a seven inch pitch or a seven on twelve roof pitch a couple common speed squares that you can find at any hardware store the real obvious difference between these two right here is this has a conversion chart and that information can be found elsewhere in the square and I can show you that later this one has an open area so that the scribe marks are available and I prefer to have that and rather than having redundant information on a square so the rest of the talk will be about the Swanson speed square in particular and its attributes and first off it's a square so you can use it to check you know the square of the end of a piece of lumber to be a stud or something and then of course marking square lines so there's your square line it also has a 45-degree leg so you can drop 45 very quickly it also has described lines I talked about earlier so there's quarter-inch lines it can scribe so that's real handy for layout it also has a ruler in a couple locations it has all the way up to seven inches out here and I think three and a half one to three and a half on this section here so that's really handy if you want to draw a line say maybe two inches from this line you just slide it out to the two inch mark draw a line and those two are two inches apart now what if I want a two inch square just mark two inches there find the scribe line now I've got a two inch square the other thing is a protractor and it has from 0 to 90 degrees and anywhere in between 1 degree increments we can take a look at our 45 degree mark that we drew earlier and line it up to the square leg and you'll see that 45 comes right through this line so that's how you use the protractor if you want to mark let's say a 10 degree cut line you would swing ten degrees to the edge from the pivot of the square and you'll get a 10 degree mark the pivots marked on pretty much all squares at this point and it usually is labeled pivot I think the other one says it too yep pivot most of them have that and that's the point where you're going to be rolling either way this is I'm spinning the other direction here's 10 degrees the opposite direction same point same reference same side okay don't be discouraged by the rafter I'm not going to talk about roof framing too much I just want to show you the other attributes of a speed square in particular the common scale in the hip valley scale those specifically have to do with rafters and in this case this is a roof rafter the edge view of the double plates of a wall and a stud and this is a 612 pitch and in this case the pivot point is sitting along the top edge of the rafter and the incline of the rafter goes through the sentient six inch mark that is a 612 pitch and it allows the 90 degree leg of the square to draw the plumb cut of the tail and the ridge and the side of the bird's mouth or what they call the seat cut in a rafter if you were framing a roof that had hip rafters or valley rafters you would use this scale so in this case I would go all the way down to the six inch mark to cut a six inch pitch valley rafter or hip rafter and the math for those is a little different I'm not going to go into it but this this Inc the set of increments allows you to achieve that pitch for your Neath also the diamond here has to do with a method for drawing a seat cut along with this little mark by the five and kind of goes through the 80 inch mark or the 80 degree mark those marks have to do with marking out cut and I'm going to show you those later remember that chart I was talking about on the other square this is how to get that information without needing this okay so let's just say that you have to build a seven inch pitch roof and you want to cut everything on your chop saw but your chop saw doesn't have the common set of increments on it it just has degrees so now you need to convert your pitch your common pitch to degrees so you can use that in this case you're going to take the pivot of your square on a straight edge and you're going to rotate until the seven goes through and you're going to look at the degree increment on the outside of the protractor and in this case it looks like about a little more than thirty of maybe I'll say thirty and a quarter and you see in this chart seven is thirty and a quarter so let's try maybe ten twelve so same thing start on a straight edge rotate until ten goes through that edge it looks like forty is what ten is so you would set your saw at forty degrees let's look at the chart yep forty degrees so this can be rendered with just the information on this there's no need for that chart this is going to be a way to find two angles that add up to 90 degrees another way it's called a complementary angle you would need this if you're going to do an uncommon miter rather than just two 45s to make a 90 or if you were doing some roof framing and you needed to know those those angles in this case this is the easy way of getting the second angle without having to do any math in your head or with a calculator you can just use the protractor to find the angle so I'm going to draw a 90 degree mark just for reference and to start my pivot point and let's just pick a number like the model 31 so let's say I have 31 degrees I'm going to roll my at my pivot point on my straight edge I'm going to roll out to 31 degrees on the protractor and then I'm going to draw a line on the 90 degree leg of the square and I'm going to spin it back make sure I'm back on my square line and I have a mark right through 59 so 59 and 31 make 90 and necessarily so because they're both inside of this 90 degrees system let's say that I have to draw an angle greater than 90 degrees say for example 115 degrees well I'm going to draw a reference line for a sake of discussion here I know that 115 is 25 degrees larger than 90 so in order to add 25 to 90 got your 90 here you just pivot your square 225 degrees strike a line and now you've got what is equivalent to 115 degrees from here to here and also it gives you a chance to find out what the difference between the straightedge and 115 is to get your supplementary angle and that's 65 degrees we talked about the diamond in this other little line on the square these are used to achieve the seat cut in a rafter and it helps you decide or determine how tall to cut this to get a width of a seat cut to match your framing lumber in this case these are both for three and a half inch lumber so to show you that I'm going to get another rafter and and we'll go through the process this is a six twelve roof so we'll do the same thing on the other rafter let's say we want a seat cut in here somewhere so I'll just draw another plumb line and what I'm doing is I'm running my pivot through the six inch mark and I'm drawing a plumb line that's just reference now what I want is kind of a seat cut here and take out this material now the easiest way to do this with the diamond is just slide it over until the top and bottom of the diamond have the line going through them and you draw your line now I'm not too keen on this particular way of doing it it renders an okay result the other method is to use the little tiny lines here through by the five and through the 80 degree mark and you kind of line those up with your plumb mark and there's a little bit more distance to to align your Square and you that up side down with your protractor marks along where the level cut of the seat cuts going to be and what you do is you line this up parallel with that line until the 45-degree mark runs into the rake of the roof though you just draw a line almost exactly the same now I prefer another method it's a little more accurate what I do is I'll take a straightedge and I'll draw my pitch I'll swing my square to the pitch mark in this case we're using six I'll draw a line and I'll get the complimentary angle in this case about sixty one two three and a half sixty three and a half I'll come back to the rafter and I'll put it back in the same orientation as with the diamond and I'll run the diamond through the line but I'll check the sixty three and a half to make sure that I'm certainly going through the complementary angle and in this case we did that all three rented a pretty good result I just like using the complementary angle because I know I'm certain that I didn't get off by using these really small references

Channel: Make Build Modify

Views: 4,457,425

Rating: 4.8365045 out of 5

Keywords: speed square, fast, easy, tool, layout tool, square, protractor, rafter square, roof, roof framing, framing square, carpentry, triangle square, Swanson Speed Square

Id: BBJHQNR05xo

Length: 12min 34sec (754 seconds)

Published: Sun Nov 06 2016