Necklace Disc

I spent the whole day making a necklace thing, made from stainless steel. My girlfriend has a necklace which is made from a piece of shell. It is a circle with a circular hole to put the string through. I measured it and drew it up in HeeksCNC. I added a couple of extra holes to lighten it a bit. I drew some text in Inkscape, wrapped around a curve. I got a bit of 3mm stainless steel from my Dad.
I made two NC files, one for the text and one for the circles.
I set the feedrates to 50.
I broke the tip of my first engraving tool.
I used another stronger engraving tool.
This did the text OK ( at 0.1mm deep ).
I did the text again, another 0.1mm deeper.
I changed the tool to the 3mm slot drill.
Again feedrates at 50. Depth of cut about 0.52mm ( 6 cuts down to 3.1mm deep )
On feeding down, it broke the tool.
I reprogrammed it with feedrates at 10 and bought a new cutter from my dad.
This worked better, but it was too slow to stand and watch. I changed the horizontal feedrate to 25, leaving the vertical feedrate at 10. Later I upped the horizontal feedrate to 40 and it was still OK. Even so, with 6 depths of cut for each profile, it took at least an hour to cut, with me standing there pouring coolant from a jug.

It hadn't cut all the way through, instead it had pushed the steel down into the wood in a bulge. I had to cut through this with a knife.
I filed the sharp edges and sanded it with "Wet and Dry".
The default vertical feedrate should be lower than the horizontal feedrate.
The profile operation, in HeeksCNC, is not remembering the previously entered feedrates.