amoolo Cobalt Drill Bit Set (1/16"-1/4",13 Pcs), M35 HSS Metal Drill Bits for Steel, Stainless Steel, Hard Metal, Cast Iron, Plastic and Wood

Excellent value, sharp 👌 biting drill.Clean hole.

Good quality ideal for drilling stainless steel

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.

Product arrived on time and did the job

Needed to drill off the head of a hardened steel Allen bolt that had been rounded off. My existing drill bits barely touched the steel and having read some of the reviews I was wary of these but I decided that I had to buy and try something to solve my problem. I kept the drill speed slow and the bit well lubed (GT85) and the first drill bit cut through the bolt head like a knife through butter. Beautiful spirals peeling away and in no time at all the rim of the bolt head popped up the drill spiral. All I can say is that these worked very well for me - others seem to have had poor results but I can't fault them.

PleasedIn use

First bits were excellent!! The next set I ordered were poor and broke on their first use!! Not happy.

Unable to drill through metal expecting better