Artu USA Inc 01505 Multipurpose Drill Bit Set

I discovered these a couple years ago while looking for a way to drill out some tempered Knife blade tangs. in my drill press on max rpm you just press firmly and watch the thing plough right through. the part you are drilling will throw cherry red shavings and while typically that's a bad sign with traditional bits, these seem to work best under those conditions. the bits don't seem to get damaged, even after several holes. most recently I used the 3/8 bit to convert some 10 round sig mags to the standard 15 round. I accidentally bought the California legal mags and couldn't return them. sig mags are made of fairly hard tempered steel and this bit converted them in a few minutes with nice fairly clean holes. you still have to chamfer the edges a little to remove the sharp edge but the bit went through like butter. I haven't tried these on more exotic hardened tool steels like S7 or 10v, and I have a feeling those kinds of steels will probably destroy the bit because they are sometimes difficult to even professionally mill and very hard on tooling. but regular general purpose stuff like 1095 or 01 haven't been an issue.

Saved the day (and an expensive part) by drilling out a hardened setscrew that some idiot had welded in place!

I drilled a few holes in high speed steel, the bits drilled just fine but in the end the tips broke off. That means for the price, it's not worth it. Compared to drilling advertising through other bits, this is false advertising!

Good bits. Can give them a lot of pressure without them breaking. Used them to drill out broken bolts in a power head. Only bad thing about them is the tips wear out fast and you have to sharpen them.

I was drilling 1/4" holes in the lip of a garden tractor bucket (to mark holes for a UHMW Poly cutting edge for snow removal). I started with the 1/8" using high speed and cutting oil (as recommended on the box - 2000+ RPM). It chewed through the tip immediately. I tried the 3/16 going slow with cutting oil. Same result. I then tried the 1/4" fast, then slow, with same result. (3) bits without tips at the recommended speed and using cutting oil each time. The bits say USA on the front but the back says it's made of "European components assembled in China". They disintegrate so rapidly I'm not sure what component is from Europe? I later drilled 8 of the 9 holes using a cobalt bit with no problem.