Walterronny

Hi there, i need to make a piece that expand a tube with size 73mm OD X 1.5mm thickness (70mm ID) , to 75mm OD , it should be to make a piece with 72mm OD i assume that would expand up to 75mm OD... does this correct? i was wondering about stretching ,etc that not be enough a piece of 72mm OD for expanding and get 75mm OD..any input¿? Thanks in advance!