Hey David. I use a 1/16th bit and cut 60 in/min and .06 depth per pass. To get 11 hours you must be cutting really deep. I only go as low as .1 or .12 and it takes me ~ 2.3 hours to carve. Try going down in .05 increments. Top text at 0 depth, Last name down to .05 and background down to .1. My signs are usually 7.5" X 18".