5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 2pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO

Cobalt drill bit worked great with tapping fluid. Used for boring 6061-T6 forged aluminum. Made sure to re-apply tapping fluid when feeling slight friction before continuing. Also used it for tapping 5mm threads in the same 4.2mm drilled hole as recommended for best clearance. Thought I wanted a hex shank but the round shank is better for less wobble and precise concentric drilling since i used a hand held drill. Worked like a charm!

Great bits very sharp

Cut through steel and aluminum EZ PZ. I used it for cutting holes in my trunk to mount a spoiler on my sports car. Worked great!

Bought this to keep in my RC plane field tool box. I'll only be drilling plastic and balsa, I don't need the most expensive drill bits available. Disappointed to see when it arrived the clear plastic cover of the bit holder case was shattered, but that's probably an Amazon's delivery/handling issue. For the price I'll keep them.

Tuff solid sturdy good price stay sharp

These actually cut into my 30 year old exhaust bolts that I've been trying to drill out for weeks. Gotta keep em oiled and go slow and they will literally shred heat tempered metal. If you see smoke you are not doing it right. Slow down, you should see long coils of metal coming down from the bit, not tiny flakes or smoke, if you see those add oil and slow down. Cobalt is a brittle metal, don't push too hard, be very careful when it finally breaks through so you don't snap them off. If you push too hard, you'll snap them off. The slower you go the better, heat is not your friend! If the bit gets super hot it will get dull so keep it oiled, keep it slow, and take breaks if it feels like the bit is getting too hot.

Functional and proper metric sizes. Used in plastics and metal.

Do Not Buy! These bits broke the first time we used them! A waste of money. I bought some good ones at Home Depot.

Buen producto. Recomendado.

very sharp & feels quality bit.

Buen producto

very sharp

Muy recomendable