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How to Cut Miters More Than 45 Degrees

– There are times in both carpentry and woodworking where you're gonna need to cut really steep angles. So in today's video, we're gonna learn how to figure out those angles and then learn how to cut them on a miter saw using a simple homemade jig. Because steep angles show up in both carpentry and woodworking, in this video we're gonna show examples of each of those. Plus, by the end of the video, you're gonna be able to use all the skills that you've learned to build a unique but simple shelf. The first step is to find a tool to help you quickly solve for the various angles that you're gonna be working with. And one of the best tools for that job is an angle finder. There are plenty to choose from, some, of course, more expensive than others. This one here is from Trend tools. This is their larger version, which has these really long blades, which makes it very useful for what we're doing today. With this tool, you could find or copy angles or you can make up your own. And those are the two methods that we're gonna be looking at today when it comes to finding angles. With that, let's start by looking at the first method, which is how to find or copy an angle. In the carpentry world, one of the most common places to find steep angles is in stairs. For example, the top of the staircase, there are two pieces of trim that come together to form a steep angle. What I'd like to do is install new pieces of flat trim here and here, and use a separate piece of base cap molding to tie the two together. And it's this base cap that's gonna require a steep miter cut. Okay, so let's look at how to find that angle so we can copy it over on the miter saw. The first thing to do is to zero out the angle finder. And for that, all you have to do is put the two blades together and click the zero button. Now work the gauge up into the existing angle, making sure that both blades are tight against each side. It looks like it's coming in at around a 42.5 degrees. Now, a common mistake here would be to simply split that angle in half, (saw buzzing) and head off to the miter saw, and cut two pieces at 21 degrees. But here is what two pieces at 21 degrees would look like. On the other hand, the correct way to calculate this would be to take 180 degrees minus the 42.5 degrees to get the complimentary angle of 137.5 degrees. Now, if you take 137.5 and divide that by two, you get the angle setting for the miter saw, which is 68.75 degrees. In a similar way, if you want to duplicate an angle with this tool, you simply zero it out and then line up the blades on that existing project. Here, for this project, the angle comes out to be about 50 degrees, which means 180 degrees minus our 50 degrees equals 130 degrees, divide that then by two, and that gives us our miter angle of 65 degrees. But wait a minute. Most miter saws don't cut beyond 50 degrees. So, how do you make that cut? Well, that's where the use of a jig comes into play. But before we look at that, let's look at the second method which is how to come up with your own angles. One of my subscribers reached out to me because he saw this project somewhere online and was wondering how to figure and how to cut for these steep angles. Because I didn't have any plans or dimensions to go by, I had to figure it out for myself. And here's how I did that. I started by taking four pieces of 1/2 inch or 12.7 millimeter thick by 2 1/2 inches or 63.5 millimeter wide stock and laying them sort of haphazardly out, until I found something that sort of resembled the example project. Then to find the first angle, I simply use the angle rule to determine the first angle. And in this case, I decided to go with 50 degrees. I then trace out the top and bottom of the piece with a pencil and then measure down from the bottom line 5 7/8 or 155 millimeters and drew a pencil line. What the parallel lines do is allows you to continue to lay out the pieces so that when you're done and everything's assembled, the top of the shelf will be sitting level and not slanted, unless that's what you're going for. From there, I transferred my 50 degree angle to the board below using the rule and continued adjusting, measuring with the gauge, making the angles, and drawing until I had everything laid out. Now that all the angles are found, let's do the math. The first three numbers are calculated as we did with the stair trim by subtracting them from 180 degrees, and then dividing by two. This angle, as you already know, is a 50 degree angle. And once we do the math, it works out to be a 65 degree angle on the saw. The next angle down here is 65 degrees. And after working out the math for this one, this turns out to be 57.5 degrees. And the last one is easy here because it's a 90 degree angle, which means that it's gonna be a simple 45 degree cut on the saw. This angle down here worked out to be 25.5 degrees. And because this piece is just ending flat to the line with no miter. You simply need to subtract 25.5 from 90 degrees, which is 64.5 degrees. And that's the angle that needs to be set on the miter saw. Okay, so now that you know how to find or make up your own angles, so you know how to do the math, let's go ahead and look at how to make the jig so you can cut those angles. So this is a jig we're building. Both the right and the left are identical. So once you make one, all you have to do is make a mirrored copy. Each saw may require the need to some adjustments to the size or the style of this jig. But the main design should work for the majority of miter saws. Both the right and the left jigs are made from one piece of 3/4 inch or 19 millimeter thick finished plywood. That's cut down to 8 inches by 25 inches or 20.3 centimeters by 63.5 centimeters. I'm gonna be using my miter saw to make all of my cuts. But if you can't, for some reason, you need to use another saw, just make sure that all of your cuts are as accurate as possible. With the plywood laying on the saw like this, measure from the right side in 11 inches or 28 centimeters, and make a mark. Swing the saw to the right 45 degrees or if you're using a different sawing method, lay out a 45 degree cut just to the right side of that 11 inch mark, and make your cut. Now take the cutoff piece and spin it around and put it on top of the other one. Line up the two pieces and draw a pencil line on the left side, laying out what is an exact copy. With that marked out, don't make the cut just yet, but rather spin the piece around and start cutting your 1 1/2" or 38 millimeter pieces that will make up the rest of the jig parts. And you may be wondering why I'm showing it to you this way. And it's simply for safety reasons. If you make your big 45 degree cut first, you're gonna be left holding smaller pieces of wood, which are gonna be decreasing as you cut the remaining parts of the jig. This jig requires that you cut six 1 1/2" pieces. (saw buzzing) So let's do that now. Once that's done, you can set up the trim off

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