Mitering a Perfect Octagon

Lots of projects call for perfect octagons like on the face of this clock and this can easily be done here at the table saw, if you have the right set-up. So, let me walk you through what I would do to get an octagon like this cut, so it comes out just right. First off, let's start talking about the material. My preferred way to make this is to start with one long piece. So, I've got one piece, in this case of oak, that is long enough to make all eight pieces that I want for the clock face. Now, notice that my parts are lettered. What that tells me is, the sequence in which they were cut. So, see how the grain comes back together on those. I'm going to pay attention to that as I cut my angles and then later as I assemble my parts, so that I get some amount of grain flow through them. Now admittedly, when I cut the angle out I'm taking some wood away, but still by paying attention to this it's a nice little detail that is gonna help make the face of your octagon look a little bit better. I've got these cut in length really, really close to what I need for a finished length. Same thing, I want to make sure that I take away as little grain as possible so that I optimize the flow when I put my clock face back together. Here at the table saw, we need to figure out what it is we need in order to make an eight sided object. So, if you take a calculator and you take 360 degrees, the number of degrees in a circle, divided by, we're gonna have eight sides, which means 16 different mating components, that's gonna give you 22 and a half degrees. In some cases, it's embedded right onto the tool, so in the case of this miter gage it says right here, eight sides, 22 and a half. Now, what you do want to do is make sure that your miter gage is accurately setup so that when I swing over here, to 22 and a half, that's the angle that I am gonna get. So, I've taken the time to setup my miter gage, make sure it's cutting perfectly and then what I know is that, when I come over here and I lock in at 22 and a half, that's exactly what I am gonna get. Now, the first step is to get our boards on here, get one end of every piece cut. Then we'll flip and have a look at getting them cut to their exact length. Now, for our next step we want to guarantee that they all come out identical in length, so I'm going to be flipping them end for end, using this flipstap in order to lock that length in. Now, part of the key to this, with any flipstap is that, it's possible for the long point of an angle to work its way under there and over time that flipstap to climb up, so you wanna make sure that, like this one, the flipstaps, once it's down, is gonna stay down, so that that length setting doesn't change on you, otherwise you're gonna lose your accuracy. I've gotta sneak over just a little bit more. Right there. Now, I'm gonna come back and make the second cut on all of our parts, then I'll show you just how well this octagon is coming out. Now that I've got my parts in this band clamp, you can really see a couple things there. One, how nicely all the joins close, thanks to the good quality cuts we got off the miter gage. Two, the grain flow that we get around this, so the pattern does kind of follow as we work our way around the octagon, of course, until we get back to the last one, my H piece and my A piece, cause those are the extreme ends of my original board. If you need to profile the edge of a board like this, the edge of an octagon like my clock has, it's better to do the glue up first, because then it's really easy to use the band clamp, then route the edge after the fact. So, you can see that using your table saw and a miter gage that's well tuned, it's easy to produce perfect joints on an octagon like this one, whether you're making a clock face or some other project, that's gonna stand up very well over the test of time.