I’ve made a lot of boxes over time, and most of them have sides that are under 4in tall, and often have a slide top so the front face is small, sometimes just 1.5 to 2in.

Well, this was a three mistake process. First, I was lazy and didn’t change my planer blades after planing some hickory. I use one set for super hard woods that trash blades, and another set for normal hardwoods and soft woods. The first set leaves a lot of marks because it has taken a beating.

So my pieces come out with some pretty ugly marks, but whatever, I’ll sand later I said.

The box is all assembled and those marks are staring me in the face. Normally I just suck it up and hand sand, but I was lazy and decided to try and use a 5in ROS on box walls that were barely 3in tall. I’m sure you can see the problem here… a good inch of the sanding pad is going over the side, and as we all know there is some flex to sander bottoms, so I accidentally destroyed the nice edge on every corner and top/bottom. It was so bad. It wasn’t even a uniform rounding.

The third mistake was more laziness and I didn’t check what grit I had on my sander. Normally I leave 120 on it and start there. Well, I’d been sanding a book matched top down and had 60 on there to quickly get a mediocre glue up seam flat.

So not only did every corner get trashed, but because of uneven pressure I took nearly 1/32 more off of the bottom edge than the top, and it looked like a literal slope.

Box ruined. Never sand a small box with an ROS that is larger than the box height.

Fortunately it was just some poplar, so I didn’t lose a valuable piece of wood.