I think I got mine on ebay but this one is exactly like mine by the dimensions they give.
https://www.the-carbide-end-mill-store.com/m5/955-4059—htc-955-4059-1-5mm-carbide-ball-end-mill-standard-length-4-flute-gp-30-uncoated.html
1.5mm cutting diameter 4 flute 5mm flute depth with a 3mm shank ball nose. I don’t use dremel stuff because their not as good as of a bit or end mill made for a actual mill. I have a mill so this works for both purpose for me. These last for a very long time, carbide is good stuff. I have had this one since this project here.
Thanks for all the great comments guys. I milled the center out using a milling machine with a DRO and one of these. 1/16 carbide 4 flute end mill. ![image]! If it wasn’t for the DRO it would make this task more difficult. The DRO allows me to travel precisely the same distance down each side. The end mill leaves little round corners on the aluminum pcb that had to be filled square. This is a pic of a amc7135 with the end mill so you can see how tiny this is. ![image]! When I…
I just found more info in that thread. Those pics contain the part number and show the actual bit, the one in the link above doesn’t show a actual pic. You really wouldn’t have to have a ball nose just a 4 flute end mill with the dimensions above.