Some Jig or trick to made this to an 40x600x8mm steel?

[samsagaz]

hi guys, i want to know if is possible to made to an piece of steel with 40x600x8mm the following modification.

I want to remove from one of the ends (40mm) to the other, so on sheet having gradually from 8mm to 2mm.


will post a pic to see if help to understand me

Sorry for my english, hope that understand me