The Padauk I bought for this project was rough sawn and quite a bit thicker than I needed it to be so I used my thickness planer to plane it smooth and to about 20mm thick.
The board was 150mm wide, I wanted it to to be 125mm wide though. This will make the depth of the finished box 125mm. I first trimmed a thin piece off on my table saw. Then I could move the fence to 125mm and cut the board to size.