ATOPLEE 1pc Cobalt Step Drill Bit,M35 5% HSS Co,Spiral Flutes and 1/4 Inch Hex Shank,Unibit Step Bit for Hole Drilling in Metal, Copper, Aluminum, Wood, Plastic,9 Steps,4-12mm

I've mostly used this to open holes in 1/8in mild steel to 10mm in tight spaces(inside a powered recliner). Between mine and another a coworker used, we've drilled out ~50+ off these holes for repair purposes with no degradation in cutting ability.I'm a believer in cobalt bits for constant steel use. Sure HSS will work for mild steel, but won't stay sharp nearly as long in my opinion. This bit also is much shorter than a lot of dedicated bits in the size range it covers which is also helpful for my purposes. Metric stepped bits are hard to find domestically so this had been great.

Makes short work of 304 stainless steel, that's for sure! Very heavy duty and well made. Drills fast and especially handy if you need to quickly enlarge a hole, but don't require reaming accuracy.

Works great for drilling holes in thin car sheet metal!

Excellent bit high-quality hardened.

Works as it's supposed to

Works great.

Get a better set from harbor freight.... This things dull...

Broke after 1st use drilling through mild 1\8" steel. Disappointed!