4AA to 4D Adapter Tube

I just purchased a new automatic trash can and it takes 4 D batteries all in series for a total of six volts. I didn't have 4 D batteries nor did I have a six volt adapter. I do have a bunch of AA batteries and a 3D printer though!

I designed this tube to simulate 4 D batteries all put together end to end. 4 AA batteries go inside. Since AA batteries are shorter than D batteries you will need to find something solid metal about 1 1/2" long to make the space in the tube. I used a 1.5" #12