Carving out a sign

hi all , so i posted up a problem with text on a oval , i fixed that problem by playing each letter around the oval, so i finish the design and got a bit of craftwood to see how it work before i cut in to the timber one… the craftwood one worked amazing , to bit cut 1/8 and a v cutter 60 degrees . timber was white cedar. so the first cut was ok , the second cut not so good , it left bits in the letters and some bit it did not cut . dont know if it could have been because the carftwood was 10 mm thick and the white cedar was 40mm , i had to clean a lot of things on each letter , any thoughts , thanks marc