Engraving is basically the same as pocketing, at least the way I set it up. RhinoCAM does have an engrave option, but it's more for chisel-type faceted text. The text here is just a channel.

Not perfect, but the lifespan of these tags with my dogs isn't long anyway. Shelby's was first, and I was so happy with it after the whole thing was done that without thinking I retracted the end mill right into the edge. (It was still rotating, so the bit didn't break this time.) I was going to annodize these blue, but the brushed finish is actually really nice. The foam version is the obligatory prototype.

Here's Version 2 in development about a year later. The dogs being, well, dogs, eventually managed to lose their PetWatch identification tags, too. Instead of ordering new ones, I decided to make new tags with all the info as Christmas gifts for them. And my mom said her Buddy would also like one.

I used a piece of busted PVC sheet instead of foam for testing because foam doesn't capture fine detail well. The engraving bits are really delicate and expensive, and I'd prefer not to ruin any by crashing the mill into metal. The holes are for reference when the actual stock is flipped over and repositioned.

The raw cutouts turned out nice. The bridges hold the working part in place so both sides can be engraved, then they snip off easily later.

The engraving is filled with paint marker.

Then it's sanded and polished a little. I found leaving the tag in the blank for sanding keeps the edges from getting rounded, as in Loki's tags below.

But I'm not worrying about excessive cosmetics since these poor tags go through hell. This is Loki's final tag after a little gloss paint, which is necessary because the bare aluminum rubs off on their manes and makes them gray.

Shelby liked hers so much that she celebrated on the counter. This actually happened, on her own initiative — in front of my mom in her own house, and she actually let it happen. That's one entertaining dog!

I also made my brother and his girlfriend tags for Christmas. They didn't get on the counter in excitement, though. The back sides mentioned something characteristically obnoxious.

Part 2, about a year later, came about because the current tags were nearing the end of their lifespan. Buddy's, in particular, looked like it had been run over by a freight train. Instead of redoing the existing design, which would have been straightforward, I wanted to create a true engraving device.

The air-engraver project is documented separately.