Hi I have managed and learned i need help and I don't no what I'm doing wrong I am useing vetric to cut out letters and numbers I put it in to computer to do 6" high when it cuts its only doing about 5" some times smaller has anyone got any tips or help I'm useing 18mm mdf and doing 6 or 7 passes as recommended by cnc people thanks my number is 07900614166 I'm from halifax