I found that most other builders didn’t care much about the cabinet backs. I agree with them but I still wanted it to look decent.
I used 1/2 inch MDF to make the back because the cabinet is heavy enough. I had to cut some special supports to hold the 1/2 inch back flush with the 3/4 inch top and bottom. I glued and screwed them to the inside of the cabinet.
Here is where you can learn from my mistakes. I made the cabinet rear top and rear bottom to match the measurements online without measuring the door opening. I should have realized that those measurements left a 49-inch opening which meant that I had to buy an eight-foot length of MDF instead of a four-foot length. Next time I will make that bottom rear portion one inch bigger so that I can save some money and some hassle.
Here’s another tip: always aim for perfection but keep a rasp and surform handy just in case.
I used Screen’s measurements to draw the hole on the cabinet door. I clamped my rulers and used my router to cut it out. Again, I am not good with a jigsaw.
I also added a support to the bottom of the cabinet door so that it has a lip that sits inside the cabinet. That way, you put the bottom in first, push it flush, and lock it closed.
That reminds me: I need to buy a lock.
Kindly ignore that white patch on the upper right side of the cabinet. I noticed a slight chip in the cabinet and threw a ton of patching compund on it. I'll sand it tomorrow and hopefully it won't be noticeable when it's painted.