The Drain Tray, NPT Part, and Drain Tray Part 2 all go together. I used superglue to bind them and then used gorilla sealer spray to coat and waterproof the entire interior. You can also use a 1/2" NPT female connector made of metal from Amazon as an alternate. It may provide a more secure connection.

The cutting guide is used to support the horizontal bars while cutting them with a dremel carbon reinforced disk. The guide also has a line to help ensure the correct cut.

The outer shell and insert work with one another. The outer shell is secured to the outer metal frame and the horizontal rods slide into the outer shell's aligned holes. I use a 2mm drill bit to refine the holes on the outer shell before fitting it with the horizontal bars. To create the holes for the M2 screws that will secure the outer shell to the frame, I drilled the four holes with a 1.6mm drill bit and then tapped it with a 2mm tapping bit.

After that, you just drop the scale into the insert, and slide the insert into the shell.