A model that has an adjustable-length spacer under the hard drive. Print four side holders and attach two of them with a screw to the hard drive and all of them with a screw to the Raspberry.

Also includes a parametric-ish FreeCAD model with a spreadsheet where you can adjust most figures in case you need to adjust them (for example, the specification for the 2.5" form factor allows for a 0.25mm variation in the width of the SSD; and you can also adjust the size of the Raspberry to fit other models). Some tolerances set manually.

Includes an optional washer.

If you prefer to have your Raspberry sideways, resting on the side holders, use the updated holder model that also includes a screw hole for the bottom of the hard drive. The minimum screw ingress acceptable to a 7mm drive is 2mm, which means that with the unmodified model, you will do fine with a M3x12 screw for the bottom mount.

Toggle parameter in spreadsheet to produce model for Raspberry Pi full size or Raspberry Pi Zero.