I have a project I have been working on for the past few months where the entire purpose was to make mortise and tenons. It is a high chair. I don't plan on selling these plans, I will make an easier version to sell. Being true to my self, I was making two, one to donate, one to sell. Each chair takes 18 mortises. So here is what I have learned so far.
First, I have a set of cheap bench chisels. I have a good sharpening system so I sharpened them up. They worked well for what I can compare it too. I did notice a couple of things with them. I have heard that the nice bench chisels are sharp on the sides. This is to cut the wood cleanly in the corners. Mine have about an eighth inch of flat on the sides that crushed the fibers. Not a big deal because no one would see them.
Second lesson was about a marking knife. I never saw the point of one. A pencil always seemed to worked for me and a knife line was always hard to see. I heard that I needed to use a marking knife on mortises so I used an X-acto knife for a marking knife. The reason is because to edge of the chisel will sit in the knife mark not on a pencil mark. This helped keep my mortises consistent in size.
The third lesson came from the dry fit. Mortises need to be cut straight. I believe it was the first couple that cut were not straight and caused the entire project to be bent out of shape. I might have been able to fix it, but I cut a mortise on the wrong side of one of the legs which was repairable. So now I am down to one high chair to donate.
I am having fun learning this, however it does take a lot longer than exposed dowels. The dry fit showed that it was a much stronger chair. Hopefully it will be completed in a month.