To keep a vice from marring a tang, I use ice cream sticks. I went to a hobby store and bought a box of wood ice cream sticks. 1,000 of them were around $5.00. I cut them to an approximate length of 1". I use one on both sides of the blade tang. I use them once and then throw them away. I've never scratched or marred a tang using them.
A.T. http://www.customknives.com
A.T. http://www.customknives.com