I recently bought a KUM long-point sharpener from Cult Pens, but I've had very mixed results using it. Some pencils sharpen well - such as the Staedtler tradition HB - but others break leads almost as soon as I turn the pencil. For example, the Faber-Castell 9008 Steno kept breaking.
I'm still new to this game so it may well be my own fault for being too rough or turning the pencils with too much force. On this design there seems to be a lot of pressure at the narrow end, more so than a conventional sharpener.
If any readers have tips on using this stenographer's sharpener, please let me know.