I posted this as an idle query in another thread, but since it threatened to derail the thread I thought I'd better split it out. My original query:
> While we're on the subject, can I ask about filing HSS? I'm interested in making form tools – I know I can heat treat O1 or the like but I'd like to avoid the extra faff. I imagine diamond needle files are the way to go here but I'd like to get one decent set that will last.
The reason I'm thinking diamond files is the shapes I need to create are quite small and while a grinder could do some of the work, I'm thinking of things like this:
The blanks were drawn at 5mm (vertical) across, and most would be in this range. The notch in the bottom one is about 1mm wide and deep.