One of my main projects recently has been an interchangeable-tip crochet hook system for sale that's based on a taper fitting instead of a discrete spring the way the kit ones use. I've successfully made one instance, but I'm having trouble getting consistency making hooks by manual filing. Partly this is due to being a bit intermittent about getting it done, and partly this is just not having developed the skill of repeating them fully.

I do think that the feel and quality of the result is quite good when I do produce a good set, but I've been considering how I can get a more predictable process.