What is good electric knife sharpener that won't ruin a knife? I use a large comercial style triple stone for myself. every few months my dad brings over a handful of his horribly dull knives and wants me fix them up. I was thinking a good electric sharpener would be a good christmas gift for him. Needs to be pretty much foolproof. I've worked in butcher shops that had knives that were sharpened by some kind of sharpening service, obviously done on some kind of grinder or machine or something that were plenty sharp. The guys in there didn't know how it was done though.