Hi everybody, I’m Mike McCrory
and this is Wood U Make It. In this episode, now that I’ve made the cross
cut sled, I’m going to make a couple of jigs for cutting
perfect miter joints. One will be for cutting 45 degree miters;
and the other one will be for cutting variable miters by attaching a simple bar to the cross cut sled. So, I created the cross cut sled out of a
5ft x 5ft piece of Baltic birch. I’m going to make these remaining jigs with
the leftover pieces. I’ve got this piece and I’ve marked four triangles
on it. And I’m going to use that — or part of that
— to build the 45 degree miter jig. And I’ll cut it a little bit oversize. [sound of the table saw] [theme music playing] Now I’m going to just cut out a strip of this plywood. [sound of the table saw] Now what I need to do is route a slot in each
end. That will give me the ability to vary this
angle. [sound of the router] OK, so here’s my first jig. It’s just a straight piece of plywood with
a slot cut in it and now I can create a miter joint at any angle that I want.
So, I’ll set it to 45 degrees. One of the reasons I wanted to build a fairly large cross cut sled like this — I have a 30″ capacity — is so that I can cut larger pieces like this, so with a 45 degree miter bevel set, now I can run along this line and confidently cut and accurate and straight 45 degree miter.
[sound of the table saw] Now I’ll cut the triangle in half and then
I can square it all up with the cross cut sled. OK, now let’s cut down the center of this line. [sound of the table saw] So, there are my triangles.
Now, if I want to assure that this is a 90 degree angle, so that I can cut 45 degree miters this way, I’m just going to use my cross cut sled that I know is square. [sound of the table saw] Alright, so I’ve got a perfect 45 degrees.
What I’m going to do, though, is I’m going to glue these two together so that I’ve got a nice 1 1/2″ thickness for mounting boards against. Then I’ll joint one edge to assure that it’s straight and flat and then I’ll come back here and square it up again and then I will put a 3″ fence made out of plywood along the side. That’ll allow me to cut higher pieces and it also gives me something to use to position
my thumbs against to hold the pieces in place. So that give me an edge to put some pressure against. The triangle is glued up — two layers — so
it’s about a 1 1/2″ thick piece of wood. I’ve also jointed it on all three sided just
to make sure that it’s nice and clean; nice and smooth. I may have thrown it out of whack by doing the jointing and doing the cutting. Oh, and I’ve also squared it up. On the cross cut sled. This is exactly 90 degrees.
And I checked it with my square. I’ve checked it already, but what I did was I checked for
any daylight showing through and it’s perfect, or as perfect as I can get it. So, just a few other checks to make sure that I haven’t thrown the triangle out of whack by trimming it. If this is 90 degrees and I want each of these
to be 45 degrees, I can check it here. That’s exactly 45 degrees. That’s exactly 45 degrees, so I think we’re good. One other final check that I’ll do. This is exactly 18″ wide at the bottom, so
I’m going to mark the midpoint at 9″ and then if I go up 90 degrees from that midpoint,
I should be right at the top of the triangle. And….I’m good. Now what I want to do is use my table saw blade to cut right down the center of that. [sound of the table saw] Now I’ll mark the points in alignment with the T-tracks where I can drill holes in my jig. Alright, so I’ve drilled the holes, and I was very careful to make sure they were an equal distance from the bottom and an equal distance from each edge. Now I will slip in the bolts, get the bolts into the holes. One of the reasons I did this cut line earlier was so that I can bring this back into the
blade and — it’s not perfect, there’s a little bit of wobble — but it helps me to keep this relatively proportional so that I have an equal angle on both sides. This doesn’t have to be perfect. As long as the overall angle is 90 degrees,
if I happen to cut one 42 degrees and the other is 48 degrees it’s still going to add up to
90 degrees. But, for visual reasons, you want to keep
this as close to 45 degrees as you can. And then as a final check I can always measure
from the cross cut fence to make sure I have an equal distance on both sides.
Let’s go ahead and put those in. Then, I’m going to bring this back a little
bit and keep it with the blade. And then I’m going to miter the ends of my
two face plates that I’m going to put here. Originally I said I was going to cut these
to be 3″ but then I realized that my blade wouldn’t be able to cut them off that high.
It doesn’t come up that high because of the fact that I’ve got 3/4″ of plywood here.
So, I’ve reduced it down to about 2 3/8″. Now I’ll be able to cut these off and glue
them on and then we should be finished. [sound of the table saw] OK, the face plates have been glued on and all I need to do now is to cut through the
end. That will give a nice, tight fit with the
blade and leave zero clearance and help to prevent any tear out when I’m cutting the miters. [sound of the table saw] And there we go. We’re done. We’ve got the 45 degree jig for cutting frames and anything else that requires an exact 45 degree miter. When I say exact, what I mean is that the total of the two pieces that you’re going
to join together is going to add up to 90 degrees. Whether it’s 44/46, it doesn’t matter as long as you cut one piece on this side and the
other piece on the other side. I’ve got this other jig for cutting any other
variable angle. I think the only other thing I might do is
put a coat of tung oil finish on this to protect it. But, other than that, we’re done. So, would YOU make it? [theme music playing]