The middle section is only tricky since there is a rectangle you need to cut out (for a hand hold) and then build a box for the back to glue around it. The cuts are easy. The clamping for glue might be tricky.Awesome job! What type of wood did you use? I just need a few pointers to get me started - my woodworking skills aren't good.
The middle section appears the most difficult to make.
I'll post pics soon and can provide dimensions if you need them. Every cab is going to have some fit and finish issues so YMMV on the dimensions. Plus I measured them in inches when I probably should have used the metric system (these cabs are Japanese).
The wood I used was 1/2" thick Sande plywood (you can get it at Home Depot in 2 ft by 4 ft sheets). I bet others have other (better?) opinions. This is close enough for me for the back doors. Again, these cabs are Japanese and used some Japanese plywood I bet originally.
