Summary

Some of the newer versions of the Wahl vibrator don't come with the wedge attachment. But now you can print one.

Instructions

Print the wedge part and the cylindrical mounting part, then file as needed and superglue them together.
Print at 20% infill using rectilinear mode. Honeycomb structures absorb vibration!
It required a bit of trial-and-error to get the cylindrical mounting part to connect with the attachment point on the vibrator. Having the file in two pieces reduced the amount of time needed to get the cylindrical part to the exact correct size. The settings in the file were printed in PLA with an 0.4mm nozzle.
The printed attachment is a little noisier than the original, but it works fine and produces similar effects.

Wedge attachment for Wahl vibrator