Some things in woodworking are just not that exciting and cutting backs and bottoms probably falls quite nicely in that category. So why am I even covering it, because I have had a number of emails and comments from subscribers on the topic and I know if a few people comment on something, there are probably hundreds who also have questions but just don't ask the questions.
So, cutting backs on cabinets or bottoms for boxes is really exactly the same thing. All you are doing is cutting rabbet around insides of the cabinet carcass to allow for the inserting of a back. The back could be plywood, or it could be a series of boards. Either way, the best way of putting these backs on is in such a way that the back of the back - is flush with the back of the carcass or it can even be inset a bit more, but definitely not sticking out from the back of the cabinet of box.
Back in the day when I first learned serious woodworking, we always cut the backs using a dado blade on the table saw. That's just the way things were done then. There wood routers, but they were uncommon, had very few bits and were really still in their infancy, so weren't even considered for this function back then ....
The only other option was to cut the rabbets with a rabbeting plane, which I have also done, and to be honest, it's not that much fun. Not that I don't like working with hand planes, I actually do love working with hand planes, I just like to work with them when you can see what the results are like. Cutting rabbets that are going to be hidden around the back of a cabinet or underneath a box are not nearly as rewarding.
Cutting backs on cabinets and boxes is always a bit frightening because you you are now working with what we call "stopped rabbets". That is a rabbet that starts part way along a board then stops before the end of the board. We do this that we don't end up with a little square hole somewhere in out cabinet that then needs to be filled with a little square piece of wood. Yes, I have done this too and have found that making the stopped rabbets is quicker and less frustrating than trying to make little square pieces of wood to and gluing them into place and hoping not to get glue elsewhere on the project that will later show up as a blemish because the stain cannot penetrate it.
Using the table saw to cut rabbets works well and if you are using it, now need to change if it is working well for you. A few years ago when I was making some sort of a cabinet, I don't even know which one now, but I remember that in my anxiety to get the carcass assembled, I had forgot to cut the rabbets in the back that would take the plywood back. I decided I didn't want to nail the back on top and that I still needed to cut those rabbets somehow. I started off with my rabbeting plane and quickly lost interest. It was big cabinet and I felt there was a quicker easier way. I tried using a sharp boxcutting knife and a chisel, but that was tedious and not very accurate. Then I remembered that not long before I had purchased a rabbeting bit for my router, and maybe this would work.
I first installed the rabbeting bit in the router table and set is all up, then I wondered why I had to use the router table? I would mean I have to hoist this large cabinet on to my router table and balance and move it around to make the cuts ... my could I not do this freehand with router and rabbeting bit? ... and so I did and it worked so well, and so quickly I started to wonder why I had not been doing this before. The results were at least as good as the table saw, and if I wanted square corners, I could still cut them out with a chisel, or ... I could simply round over the corners of the back and get a custom fit. You can't tell from the inside of the cabinet that the backs are rounded over, only if you look at the back, and when you do, it looks kinda cool !!!
Hence was born, my new way cutting rabbets, well, new for me, I'm some many, many other woodworkers are already doing the same thing, but for those who aren't here is yet another option for you to consider ..
Copyright Colin Knecht