amoolo 5/16" inch Cobalt Drill Bits(10Pcs), M35 HSS Metal Jobber Length Twist Drill Bit Set for Hard Metal, Stainless Steel

This doesn't work as expected. Too high price

Bits work great and at a great price

I bought these drill bits in 1/8 1/4 and 6.5mm for drilling out stainless steel rivets. They worked very well. Drill at slow speed for best results on SS. The 1/8 size, extra care is needed as they are small and break if to much pressure is used Never broke any of the larger sizes

very durable and cuts clean, sharpness last long depending on how you use it

Good quality

Proved ideal for drilling out a stripped Torx stainless steel screw, whilst cheaper that M42 cobalt bits. I've not cut hard metals before, so I did some research first, which proved essential: Stainless steel is very tough and generates massive heat when cutting. Red-hot temperatures can be achieved within seconds if cutting without regular applications of lubricant, so be cautious and keep your cuts small. Stainless Steel DO's: ALWAYS use lubricant - WD40 is fine. Apply HIGH pressure. Use LOW drill speed - If using a power drill pulse the drill to prevent high RPM. Allow the bit to COOL between cuts and apply fresh lubricant. STEP UP TO SIZE - drill incrementally larger diameters holes BEFORE drilling the desired diameter. Stainless Steel DON'Ts: DRY CUT - without lubricant, your bit will BURN within seconds of starting. Use HIGH RPM - excess heat will cause the bits cutting edge to deform. Use BLUNT bits - if you can't see 'wiring' from the cut, it's blunt. Cut TOO MUCH at once - you'll FLATTEN the bit heads. Use the WRONG bits - don't use masonry or wood bits to cut metal. It won't work. Most of these tips come from makeitfrommetal.com 'Pro Tips: How to Drill Stainless Steel'. I found Johnathon's guide extremely useful, and hope others will too.