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

Needed to make a tight 10mm hole in a collar I was machining out of aluminum. This bit worked pretty well. I only used it for the final cut though, so just removing a few thousandths of material. Worked out well though and no damage to the cutting edge or flutes. My hole diameter came out to within .002 inches of 10mm. If you need a metric drill bit for a tight hole, this would work.

Very good drill , was able to drill 155 hole in 1/8 thick stainless steel with one bit and no lubricant . I have reprder different size due to good quailty for another project,

Tuff solid sturdy good price stay sharp

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.

Works for what I needed it for

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.

Installing stainless steel cable rails. The bit included with the kit wore out after drilling 5 holes. So far I’ve used one bit for 10 holes and it’s still boring holes. Definitely recommend for stainless.

It couldn’t cut a hole on thin stainless steel sheet at all. Expected much more.

Buen producto. Recomendado.

very sharp & feels quality bit.

Buen producto

very sharp

Muy recomendable