14-Pieces Screw Extractor and Left-Hand Drill Bit Set, Easy Out Broken Bolt Remover Reverse Cobalt HSS Steel Drill Kit, Ez Out Stripped, Rounded-Off, Damaged Bolts, Screws&Studs Removal Tool(Yellow)

I needed these for a broken M10 stud that was a motor mount .. grade 8.8 drilling so the bits needed to be cobalt not HSS.. so many are sold that claim to be cobalt but fail when you put them to something hardened like an 8.8 or grade 10 bolt... these did the deed with no drama but required care and proper drilling technique to have them work properly... if you spin these at 3k rpm ,with no lubrication and light pressure, you will assume they dont cut...Thes cobalt bits literally carve and chew thru hardened steel but need Low rpms, cutting oil and some decent pressure on the drill.. the flutes need to be cleaned every 10 secs and relubed ect.. with that in mind, these cut like a knife and do not snap or dull..I went thru 1.25" for hardened stud and out the other end, then went progressively larger to widen the hole... Dont start with the tinest bit,applying pressure and not expect it to snap.. use common sense here.. I started with a 3/16 bit for the pilot hole.. these are left hand bits so it goes without saying, make sure the drill is spinning counterclockwise.. do Not overtorque the motor when these begin to bite hoping to back out the bolt.. thats where Any bit could snap.. commonsense... drill larger till little of the shell remains.. I am hesitant to try the extractors because Thats the part most people end up snapping off in the process of extraction.. its safer to drill it out and retap if needed.. anyway, Great Real cobalt bits , beautifully packaged, includes a punch and matching extractors.. great price..

Best value for money on Amazon. Even though I haven't used it as yet, I am confident it will do the job effectively. Built quality seems top notch.

For my application, to remove a stainless steel bolt from an electrical box outdoors, it barely made a dent on the broken screw.. I tried slow, I tried fast and used lubricant. Since the exact material is not specified, I am assuming it is 35-CR-MO carbide, which in many cases would work, just not in my application. I will be buying a M42 left handed carbide bit to make the extraction. I have included some photos

Outstanding product for the money.

Wow, very nice . Good quality . Best one out there . Made in USA . Lifetime warranty . Look no further .

This extractor kit works well and made well.

Perfectos lo que necesitaba

Broken immediately. Using on car engine. Not sturdy enough.