Angles of attack

Now time to cut some angles and finger joints. The two angled cuts need to be done at 98 degrees. This joint is where the seat and back come together. This is super quick and easy. I just set the table saw at 98 degrees, and make the two cuts.

 
Ta da! Finished already. Look at those sweet 98 degrees in all their glory!

Now I know what you’re thinking, sheesh, this chairs seems to be coming together pretty easily. It doesn’t look too hard does it?

WARNING: The above steps is ridiculously easy. Things from this point on get difficult. Way difficult. If you have young children, or are the nervous type, now is your time to erase this bookmark, and maybe go here.

Next step; I'm going to cut the joint where the seat and back come together. The Cassina version uses a dovetail joint, but since I have no (expensive) dovetail jig for my router, I will be using a finger joint. I've set up an old sled (previously used for dado cuts) and made a few modifications to it.

So what I've done is take 2 pieces of MDF, cut a 98 degree angle on one edge of each piece, glued them together, and then glued them to the sled.

So you can see here what they look like from the side. These two pieces are supported by a few other pieces of MDF glued to the sled.

Now I get my dado set out, and install the blades and cutters.

 Ooooooo, look at that, it looks like an angry shark ready to rip something apart.

Now I lay out the areas to be cut. 

I made a test cut, and it's perfect! No kidding, first cut with the dado's and it came in perfectly. This rarely happens.

I put the first piece in place, and check the alignment carefully.

 

 

I made the cuts, and they look good. Nice sharp edges too. 

I put the baord back in place to show how it was cut; I had C clamps on either side to make sure the piece did not move when being cut. 

Using the cuts in the first piece, I laid it on top of the second piece and traced the areas to be cut. This is the back piece of the seat, and these joints are wider. It will take about 1.5 passes with the dado set for each cut to create the right width.

Now all the cuts have been made. So far so good. Here's a word of caution: when making these cuts it is VERY important to carefully mark out the front / back of each piece, and triple check where you are cutting. At this point it would be very bad to accidentally make a cut on the wrong side, or a wider cut when it should have been narrow. "Measure twice, cut once".

I fit the pieces together, and a few of the cuts were just a hair off, so I had to sand some areas. An hour later and they fit great; nice and snug, but not too tight.

Here's how it looks from the side. A nice clean fit, and looking great at 98 degrees. This is a relief. This step was difficult and nerve racking. But now we can go do a few other things that aren't too challenging.