I have multiple gauges with varying curvature. I fear that if I use a flat stone, the curvature might get irregular.
ceramic rods
touching up regularly to keep gauges sharp is much easier than dulling the edges and needing to resharpen
Mini belt sander/sharpener, belt should contour to the blade shape. I got a cheap one from Amazon works well for most tools.
https://www.amazon.com/gp/aw/d/B07CVN8HV5?psc=1&ref=ppx_pop_mob_b_asin_title
belt sander removes too much material very quickly
Variable speed and fine grit. I have used the one I linked a ton to sharpen all sorts of tools. Also it’s literally listed as a tool sharpener.
veeeeery carefully
jokes aside, an outside radius you can do without a problem on a flat stone, on an inside radius either get yourself a round stone, or wrap sandpaper around a dowel
Find someone with a Tormek sharpening system with the woodturners kit, and beg to use their Swedish shapening marvel.
Convenient way is sandpaper and a dowel of a similar diameter of the gouge. The best way is to get gouge sharpening stones because I hate sharpening on sandpaper.
