Here's my take on a straight Morse code key!

Non printed parts:

• M3 hardware for the contacts, stopper and spring holders. I used 15mm & 25mm lengths but you can get away with longer lengths and cut them down etc.
• M8 bolt and nut for the bearing axle. 45-50mm length.
• 608zz bearings (22mmOD x 8mmID x 7mm thick)
• Any old wire as long as the OD is less than 3mm to fit through the holes.
• Couple of crimp ring terminals to fit M3 screws
• Tension spring (I have a collection of springs as I always keep them from stuff so cant link a source but the centre distance of the two M3 screws when the lever is flat is about 27mm so you will want a spring shorter than that to create tension)
• 4mm Banana plug binding posts from Ebay >>> https://www.ebay.com.au/itm/4PCS-New-4mm-Banana-Socket-Binding-Post-Nut-Banana-Plug-Jack-Connector-AS/183599007580?hash=item2abf5a875c:g:WHcAAOSwqfNXoweU

Note: It's still a work in progress and needs some improvements - there is a fair bit of slop in the axle assembly both laterally and vertically but it gets the job done for the moment.