I did a search and didn't really find anything. Forgive me if this has been asked before. I like to make hidden tang knives with a pierced guard. I don't have a mill so I drill holes and connect them with a file or dremel and then file the slot to size. I may leave a little more filing than some guys as I have missed the mark a time or two by drilling the hole to close to the size of the slot. I generally get a pack of the cheap HF needle files with the plastic handle and then just toss when they don't cut good anymore. I would be glad to know if there are needle file that remove more material faster. Wouldn't mind paying extra for that.