KnKut5 Piece Carbide Tipped Hard Steel Drill Bit Set

I was a Machinist Mate in the Navy, been a Mechanic for 30 years, normally use Jober drills, or general purpose drills. I have use high quality drills in the past. I got a stuck valve in a valve body with no way to remove except drilling it out. It is 50-60 HRC... and my normal drills, plus other high quality tool steel drills wouldn't touch this. Read the reviews, I 100% support and recommend this drill kit. It cut like butter...low and slow and plenty of oil...drilled no problem. East out was abke to grab and extract. Ended up being bad grind...oversized.

Good product, just what I ordered

The description says you can use in a regular drill but they will snap in a hurry. They work great in a stable drill press. I was drilling a grade 8 bolt out of a trailer hitch and snapped 3 of the 5 bits in the set. When they were cutting. they cut fast.

I ordered a replacement set and am returning this set, because one of the drills (the 3/8s) has some dark spots and streaks that I am concerned might be corrosion. I used a penny that I had on hand to pry each drill out its cutout in the black foam liner. The fit of each of the drills in the foam liner is tight, and the smaller diameter drills fit deeply in the liner. Sizes are marked on the shanks of the four larger drills along with "USA," but I cannot see the sizes to read them while the drills are in the foam liner. I did not find any markings on the smallest drill, probably because its shank is too thin for markings. The drill sizes are not marked on the case, which is metal. There are tool marks in the flutes of the drills. The marks are especially noticeable in the larger sizes. I do not see any issues with the business end (i.e., the tips) of the drills. However, not having used the drills, I cannot comment on their effectiveness.

This was my last resort after my cobalt bits failed.

I liked the bits I used it remove a broken tap

The manufacturer claims that these bits will drill through hardened steel, including broken off easy outs.. I have a set, and I will tell you that the claim is 100% accurate.. I just wish they sold these individually.. I primarily use the size in the middle and I have completely wore it out.. Cconsidering the aggravation of trying to work through broken off taps and easy outs, I suppose it is worth the price for the whole set even though I only need one of the bits !