What I need is I have the 3/8 one and need to know what size to make the slot, and what do I need to make it. I have a mill but it is 1/2 , Iam new at all this. It took me a 4 weeks to figure out how to run it, go thing for youtub, What Iam doing is making a milling plate out of 6061. It is 24in, long 9in wide 1 1/2thick, got it cheap thanks Brett