This pen was my last prototype fountain pen and has been in use continuously for six months to determine its durability - and survived the experience well despite the fact I'm notoriously hard on my pens. The Blue and Black Pearl blank I used is absolutely gorgeous. This pen is one of my favourites even though it's design leaves something to be desired. The section shape could be better (see my pre-production pens) and it needs to grip the feed rather better. The cap to barrel thread is a single start, but none the less, it works well. The black finial and brass ring were an experiment that didn't entirely work, so I've simplified the design since.
Next to a 1948-1954 vintage Onoto 6233 in blue Celluloid.
The pen has a friction fit nib and feed inside a black Delrin section. The cartridge convertor spigot is machined into the back of the section. The pen is very light, and with its section shape it can be used all day. The dimensions are as follows:
Length Capped: 145mm
Length Uncapped: 132.5mm
Length Posted: 185mm
Barrel Diameter: 12.0mm
Cap Diameter: 14.0mm
Weight: 19g
This pen convinced me I was on the right track and gave me the confidence to invest in a triple start tap and die to get a better cap to barrel engagement. The clip is machined from brass sheet, and is not really nice enough or quick enough to make to be viable as a production design, so future pens will have bought in clips.