Probably a good time to talk about tools. So if you don't like to read about tools, then skip this post. Actually, if you don't like to read about tools then you probably shouldn't be wandering around in this section of the Forum.
I have always enjoyed working with wood, everything from framing to furniture and have a lot of tools. I did need to add a few to get this job done though. I mean what worthy project doesn't need a special tool or two (or a dozen)? For once, I did try to limit my purchases to the bare essentials as I am pretty sure this will be a one and done project. If you were going to do this for a living then there are much better (aka more expensive) choices that one could make.
First off I needed to either get comfortable with doing a lot of hand sawing or I needed a portable saw that could cut at least 3" depth for the tenons. Several manufacturers make 10 1/4" and 16" beam saws. These are just very large circular saws in either worm drive or direct drive configurations. I never knew such an animal existed and have lived in a 7 1/4" circular saw world my entire life - amazing. I already have the Makita 36v 7 1/4" cordless worm drive saw and really like it so I opted for the 10 1/4" 40v worm drive Makita cordless. I never really considered a 16" version as that just seemed like a recipe for disaster. I guess if you were cutting larger beams, like 8x12 then it might make sense. So far the new Makita has worked really well and isn't particularly difficult to handle.
Next up are timber framing chisels. You can spend a lot of money on these and for these I went to the upper end. Since my mortise joints are all 2 inches wide, I needed a 2" chisel. Every article I read touted the 1 1/2" chisel as indispensable for timber framing so I bought one of those as well. I went direct to Barr Specialty Tools for these. They are hand forged in Idaho and are truly works of art. Seriously considering framing them and hanging them in my shop when I finish this shed.
You also need a heavy mallet that you are comfortable using. I have lots of rubber and various dead blow mallets but for timber framing you need a wood faced or rawhide faced mallet. On the advice of Mr. Barr himself I went with a Garland 40 oz rawhide mallet. It is very comfortable to use. I also bought a DMT diamond faced honing stone (fine and coarse) but these chisels are so sharp I am not sure I will need to use it for this project. Time will tell.
One way to cut mortises is to buy a chain mortise machine. They are not cheap. At the opposite end of the spectrum you can just cut them by hand with chisels. Given that this is a one and done project and I am also a mere mortal, I opted for the in-between solution which is to drill out the bulk of the material and then use the chisels to finish the mortise. There are lots of different wood drill bits and you will get both advocates and naysayers on the internet for every single type regarding their suitability for hogging out mortises. I opted to go with a special forstner bit made by Famag and called a "Famag Bormax". They are a German company and make them in metric and imperial sizes. I needed a 2" and an extension as my mortises are 5 1/2" deep. This bit has worked phenomenally so far for me even though many on the timber framing forums don't like forstner bits.
Some miscellaneous smaller ticket items. I needed a smooth cutting 1" bit for the pegs. I went with a 12" Wood Owl Ultra Smooth auger bit. It cuts fast and smooth. I might have considered it for the mortise hogging but they don't make this bit larger than 1 1/2". You need a good handsaw. I have lots of handsaws but many timber framers swear by a cheap Stanley 20" tradecut. I have to say it is sharp and fast and for the price disposable. You also need various squares, framing, speed square, combination, etc. I had everything but a large enough speed square so I picked up a 12" aluminum one. You also need (or at least I need) someway to drill straight holes for hogging out the mortises and also for drilling the peg holes. I looked at various portable drill presses but in the end went with some simple right angle blocks that you can use to guide the bit. They aren't perfect but so far they have been good enough. There is also a technique where you drill a hole in a plastic mirror (like a CD or DVD for example) and use the reflection to keep you straight. I haven't tried that yet but might give it a shot for the next batch of peg holes.
Then there are the tools that most of us have laying around: tape measures, large framing square, carpenter's pencils, etc. I can't really think of anything else I have used so far. Oh I forgot, broom(s), flat shovel, and a shop vac. Mortise and tenon joints make mountains of wood chips and sawdust.
Also these 45 degree joints are very different on the tenon ends of the braces. Plan on starting one today so will report back later on degree of difficulty. 
