The first Chester 12" 3-in-1 I bought would not operate alla three funsctions due to the moving beam being machined incorrectly. No spares to hand, so the machine was replaced & the second one works fine.
The quoted 1mm capability in steel is an effort to shear, though I have used mine mainly on sub-1mm aluminiun for which it is quite easy..
It has not had much use & is currently greased up under a bench pending sale – it is in the small ads on here , collect from Huddersfield for a lot less than a new one, plus it has already been deburred !
Nigel B.