Hi Jack
You are asking the $64,000. dollar question (am I dating myself). At any rate you might look back trough the past postings. I myself have brought this question of cutting speed up in the past, but never received a clear answer. The question is not how long it should take to cut a rock, but how long it takes your rock vise with no rock in it to travel one inch and what this vise travel range should be for a relative medium hard material to rock that is really hard. Of coarse there are a lot factors that come into play when selecting a rock vise travel speed, but after hardness of the rock. The second most important factor to consider is the amount of contact the blade has with the rock. On your rock this could as much as four to five inches. But this still dose not answer your question. From what I gleaned from past experience I would say your speed of 30 minutes sounds ok, but remember slower is always better unless you have a lot of money to replace dished saw blades.
Good luck and please keep me posted on how this speed question works out.
Bob

From Bob Place - February 01, 2010 at 10:50:40
Email: replace[ ]tds.net

Message: 68730