Chiloskit 5pcs M3-M8 Pilot Slotting Counterbore Mould End Mill Cutter Solid Slot Countersink End Mill Drill Bit

These have no problems counterboring some extruded v-rail for 3D printer frames.

Worked perfectly for counterboring a steel scope rail.and they are extremely sharp,they cut through steel like butter

Picture attached has my own labels with my own measurements of each size. I've cut 1018 steel and 304 stainless steel and plastic. They seem to do the job. As for packaging labels, they where hard to read, thus I relabeled them. Keep them oiled for rust prevention.

Good quality at a good price. Thanks.

I drilled 16 5.5m holes and needed to counterbore the 16 holes. I ordered these Pilot Slotting Counterbore End Mill Cutters to use and after 3 holes the pilot tip broke and now I will have order another cutter to finish my job!

The edge that cuts the bottom of the hole should have a rake ground on it so that it cuts. I used the M3 size on aluminum and really had to crank on the feed handle. I can't imagine this working in steel.

Everything

For m5 button head screws, you need a cutting diameter of 9.5mm, and for m6, 11mm. The product description states that these are the cutting diameters, but they’re way off from what’s actually received. I contacted seller and she offered to refund 50% of the purchase price if I keep it, but why would I keep these expensive paperweights? I exchanged the first one for a new one to get the correct product. Second one I received was the exact same dimensions as last time. Overall, no, these do not work as stated and if you need the correct cutting diameter listing, order a different brand.

Vendor sent 2m3pieces There was no m8 as stated in specs