I bought a set of MT3 collets from RDG and they woudn't hold the tools , I have some metric collets also new these held well , comaring the two the scuff marks on the metric ones were at the larger end and the RDG ones on the smaller end , as this was solid no wonder they didn't work , turned down a mandrill and clocked up a 20mm metric collet , turned down to 3/4" and ground off 0.002" this made a huge difference in the holding of a tool , did the same for the outher ten , only had one oops set the paper alight covering the bed .
