Hi I'm new to ER collets and have just bought one marked as 6-5 which I assume should cover the range 6mm to 5mm. However while a 6mm silver steel rod fits ok when the collet is out of the nut, it is an extremely tight fit when mounted in the nut, so much so that I worry that trying to get a 2mm rod in a 2mm collet would be near impossible without bending the rod. My question is, should these collets cover the complete range quoted eg 6mm to 5mm, or does the range mean 'slightly less than 6mm down to 5mm', in which case a 6mm rod would be a better fit in a 7mm to 6mm collet? Would the alternative of using a 1/4" collet (if such were available) when the 6mm rod would be in the middle of the range be a better solution?
Any thoughts?
Pat