How would I cut out lettering from a stamped piece of thick-sheet metal I have a piece of thick-sheet metal that has letters stamped in it that looks like this 

to which I am looking to cut the lettering out of the metal.  I am curious what tools would work for this?  The metal itself isn't too think, but is thicker than a normal piece of sheet metal.

I have seen a few metal cutting tools, such as snips and nibblers, but they cut through the metal to get to their point of interest, which I only want the lettering to be cut.  I have also read that laser/water-cutting nozzles can get caught in stamped grooves, which could damage the nozzles, so that option is out.

I originally was looking to get one of these tools

https://www.amazon.com/SCRAPER-SC-1000-DEBURRING-TOOL/dp/B006KLGZJI/ref=sr_1_15?ie=UTF8&amp;qid=1475102130&amp;sr=8-15&amp;keywords=deburring+tool+noga

and try to shave off little bits of metal alone the way.  This would be the most tedious, but would probably produce great results (I hope).

I am curious if anyone have any recommendations on what tool would be useful for my needs?  I think the grooves would provide good support for this tool so it wont cause mistakes, and I think that since it's stamped, it should be easier to cut through?

I also am looking to provide additional lettering (non-stamped) and curious if this tool would work if I had some sort of stencil/guide as well?

Thanks.
A jewelers saw (also known as a piecing saw) should do the job these have very thin, fine toothed blades, almost a like a flattened wire which can handle very intricate cutting jobs. 



Image from micromark.com

You may also want some needle files to tidy up the cut edges afterwards. 

You will need to drill a small hole where you want to start the cut. Then you can disconnect one end of the saw blade from the frame, thread it through the hole and reattach it. 

These saws to take a bit of skill to use effectively but if you get the basic technique right you can achieve good results with care and patience even if you don't have much experience. The big advantage over power tools for something like this is that you have a lot more control over the rate at which you cut so there is less chance of making mistakes. It is also important to use the correct blades for the job, which is largely determined by the thickness of the material. If you use too coarse a blade for the thickness of the material it will tend to snag and jam. For metal around 1.5mm thick you are looking at around 50 teeth per inch. 

Similarly you need to set the correct blade tension (do this by flexing the frame of the saw against the bench as you attach the blade), it should give a clear 'ping' when you pluck it like a guitar string. 

Also bear in mind that the teeth are directional and conventionally you should be cutting on the pull stroke (downwards if you are using a bench peg) this means that the work is pulled into the peg, keeping it stable and the blade is only loaded in tension.