Being the skinflint that I am and reluctant to waste my stock of solid brass rod I salvaged part of the old tap for the ferrule.
The ferrule is quite thick walled, it adds weight to the business end and I like it that way, the rear finial on the handle just locates above the thumb-forefinger joint.
The Split Wedges were from the tap but are basically piece of 3/8" brass rod, sawn down the middle, filed flat on the inner surface and re-assembled with a sliver of card material between and a drop of CA, turned to size, domed and slight taper machined on them, then split apart with sharp knife.
I used the metal lathe but you could use wood lathe and HSS tools for both jobs.