I'm at a loss from a technical standpoint on why you'd ever want to engrave something like that so deep. What's the point? Does it make it more readable? Does it make it last longer? It doesn't ADD anything to it for me. In fact, I think it looks worse than if you would have done it on the surface or very shallow. Plus that's a TON of heat to be putting into something, while removing that much metal.
The photo on the right of those 3, I think look horrible from a quality standpoint. Just my opinion.
Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
Router : ShopBot 48" x 96" CNC Router Rotary Engravers : (2) Xenetech XOT 16 x 25 Rotary Engravers
Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.