Been a long time since I've notched out a 4x4, I used to use a speed square for this job and cut from the "outer side" first.

Not bad, I have used this method before but a tad different, I'd cut the sides first then bang out the middle waste with a chisel and mallet, a couple whacks and it's out in seconds, then clean up the bottom by moving the saw side to side. But ya, great technique.

 

On that same note, this same operation can be done with hand tools quicker than the power saw, while he's spending all that time going back in forth with that thin kerf blade to clean up the middle waste, I'd already have the two sides cut down and the center banged out, and cleaning up the bottom.

But again, it's another great tip to skin that cat! Thanks for the video!

 

I liked it for the accuracy at the end of the cuts.  I wouldn't cut it all out either.

Thanks Dan. Good example there's more than one way "up a tree".

Thanks! Looks like that hammer is about ready for a better handle