The hole for the thumb stud for the Benchmade 670 is beveled on the stud side, but not on the screw end side, and therefore switching the stud around does not work (the screw end protrudes when switched around), so am wondering what's up with getting this model to work for a lefty other than using a dremel to bevel out the screw side? Have tried looking at the Benchmade site, but no info there. Any help appreciated. (NOTE: answered my own question after having finally reached benchmade customer service and was told that while the 670 orginally came with ambidextrous thumb studs, it is now strictly right-handed and benchmade would have to retool for the blade to fit ambidextrous studs, as I had determined after having takng the stud apart and examined the way the holes were formed on each side. Too bad they don't mention this on their web-site info for the 670, although, in truth, they do tell you if a particular knife has an ambidextous thumb stud if you happen to be looking at a model that has one. Guess I'll make my own mod.)