3D printed massager. Weight is a large nut placed within the rotating component.
The motor is reclaimed 12V motor from a old printer. The spring is from tractor motor valve spring and the shaft connecting head to body is 3mm 3D printer filament. The filament part is the only one that could wear out but its flexibility was more important. The tractor valve spring is a little on nonflexible part of the spectrum but it enables you to press in without much flex.
The valve was covered with an electrical shrink tube to reduce the possibility of getting anything pinched in the spring.
There is no power on/off as it was added to the power cord.
All files can be found on the GrabCAD page here.
