I got the plan for this dovetail cutter from a Randy Richard video using a screen grab (he’ll email you a copy but it was easy to just grab it). It’s a sweet design using common TPGB321 inserts ($7.25 from Enco). I got these when I ordered the parts for making the champfer tool and made the bozo assumption that all 3/8″ IC inserts used the same screw. Well, no, the fourth letter (“B”) describes the hole (and counter sink) and chip breaker. And B is a 70-90° double countersink vs the 40-60° double countersink of T (CCMT). So the special screws I bought will have to wait for another project. But, at 82°, common flat head screws seem to fit well, in this case a #4-40.
I didn’t have any dovetails to cut so I did a test using it as a fly cutter. It did really well on this semi hardened steel, very smooth, I was a bit worried that large flat part of the cutter would chatter.
The cardboard is a cardboard box blast shield to try and keep the chips somewhat contained (and out of my shirt/hair). The unfortunate side effect is that it acts like a popcorn popper with the lid off.