1/4 Inch Cobalt Drill Bits 5pcs Heavy-Duty Metal Drill Bit Set for Steel, Cast Iron (1/4" x 4")

These worked exactly as expected and I am very happy with the purchase!

I used these drill bits to cut 3/8" holes in mild steel angle iron and tubing pieces. The steel material I had to cut through was real, 3/16" thick, not the 1/8" cheap stuff from the hardware store. I was really impressed how easily these bits cut through that steel. The holes are straight and smooth, really professional looking. There was no wobble to the bits in my drill press. The pilot part of the bit kept the bit travel straight. I've drilled 20 holes so far (about 4 inches of steel) and still on my first bit. That bit isn't showing any signs of slowing down. I'm very happy so far.

Nice

These were very sharp and cut through mild 5/16 steel with ease. The downside is they are very Brittle. They work perfectly in my drill press for normal drilling. I use these for horseshoes that sometimes need to have a rectangular hole enlarged. While drilling round holes in a rectangular opening is not ideal, nor their intended purpose, its often what I need them for. Other brands took my abuse with less breakage. Even with a good lubricant i snapped bits. Needs a light touch but ok for the money.

I built a no weld go-kart out of steel. As you can imagine I had to build brackets for everything so that everything could be bolted together.For the bolt holes, the thickest steel I drilled through was cold rolled quarter inch steel. These bad boys pierce right through on medium drill settings. You definitely need a sturdy, variable speed, reliable drill and of course a good punch to start your holes.Unfortunately, I cannot say how accurate the starter tip is, as even with using a punch to plot and start the holes, the bit/hole "walked" a bit at the end of the day. Note that I was drilling this freehand without a drill press though.. I'm sure a drill press would have made things a lot better. Out of 5 bits in the pack, I drilled hundreds of holes and still have one bit left over. I would definitely recommend these.

I do a lot of holes in hardened steel and steel up to an inch thick. These cut right thru most things.

slow cutting on steel perlins

Good quality. Haven't broken one yet