[Brightcolours]

 Well , after a battle on the lathe infinity focus is achieved.......however the war is not over as every now and then at infinity focus the mirror just clips the rear element.....focus a little closer and all is fine........so a couple of mm will be required to be removed from the rear element's housing, there is enough meat there fortunately.......will do that tomorrow!

Which reminds me to take my EF-S 10-18mm IS STM for a spin again today (on my 6D... Talk about the possibility to hit the mirror ). Don't forget to paint the bare metal surface black again! Jealous of your lathe ability and skills.