What is the easiest way to hone a marble wall? It is taking forever to hone with a small three inch diamond.

You are right. It will take forever to hone a wall with a three inch diamond. The fastest way is to attach a seven or eight inch drive pad to you hand machine and use a diamond that is at least that size or you can arrange three-three inch diamonds on your pad drive.

TIP Several marble and stone tool suppliers make larger machines that are capable of honing and polishing wall surfaces. There is also a flexible shaft machine which is somewhat lighter than the conventional electric polishers.