I run most of the indexing for our company. I was curious about the coefficient of friction. The machine gives the gap in MM and " and the coefficient of friction. How is this number configured? And what range is acceptable? I have had guys to tell me to spray the skirts with silicone but if this is a friction test that seems to be defeating the purpose of the test. I look for the gap to be below 5mm. I haven't had a inspector fail any of my units but I'm just curious.