First off the bits are supposed to last 400 to 600 hours (thats what the rep told me when I bought my first one) From experiance I can tell you it will take abought 3 hours or more per peice that you are trying to make. It all depends on how much detail you put into it. And also what quality setting you have it at. I have done similar prodjects at best quality and thats where I get my time frame from. It doesnt seem to matter what kind of wood you use because the machine doesnt go any faster or slower based on the type of wood you use. GOOD LUCK..
Teach the little ones right, they are our future.