2/Pack Solid Carbide Drill Bit for Hardened Steel Hard Ness HRa 91.3 Aerospace Standard K20 Tungsten Carbide Jobber Length Twist Drill for Metal 118 Degree Four Facet Point Fractional Size (1/4")

I rarely write reviews. However, I had to write one for these bits. They are AMAZING. Ate through my hardened steel like a hot knife through butter. Are they expensive at what is effectively $20 per bit? Yeah. Are they brittle and can break easy if you are ham-fisted with them? Oh yeah. But do they work and work WELL?? Absolutely! I can vouch that they are WELL worth the money! If you are on the fence about them because of the price, buy once cry once. These things are great! Take it slow and easy, and use a press instead of hand-held if you can (though I used them hand-held and didn't have any issues with breakage). I didn't even need to use any cutting oil, though that would be ideal. These bits spat out the finest steel chips I've ever seen. Like shiny metal shaved chocolate on a mousse! I can finally say that I know what it's like to use quality drill bits, 'cause these things rock!! MILES beyond any other bit I've ever used! Get 'em and you won't be sorry.

Before ordering these drill bits from Mars-Tool, I thought I'd save a little by buying one from a local big box home improvement store, then a second b big box home improvement store, and finally from an auto parts store.. The packaging for all 3 bits claimed they would cut metal. None of them did as advertised. These bits did the job.

I purchased two of these to drill out a hardened steel bushing on my mini excavator for a grease fitting. The first one I broke right away using a hand drill and realized these are extremely brittle. The second one I took my time with and was a steady and smooth and patient as possible. I was able to drill out both holes. I have a high quality cobalt drill bit and it didn't not do anything to the hardened steel bushing. One started this bit drilled through it pretty easy. I made sure to keep oil on it as I drilled. Very happy with the product.

Don't hesitate to buy these drill bits. I broke a bolt extractor off inside of a glow plug and was in big trouble. I went to every hardware store and bought all of the best drill bits of different brands. Went home and six drill bits and a couple hours later I was only able to drill a small simple in the extractor, not much bigger than the center punch mark that I had made for a good center start. I took a break and got online and found a video on these bits, which had a link to Amazon . I bought them and within 24 hours they had been delivered. During that 24 hours I had tried a few more times to find a drill bit locally that would actually do more than just spin without actually getting anywhere into the extractor. I really didn't think these were bits from Amazon were going to do much more, but I had a little hope. I put the 1/8" drill bit in my Dewalt drill and slowly started to drill at a slow speed with little to almost no pressure and to my disbelief all of a sudden long metal shavings were falling out of the broken bolt hole........I could not believe what I was seeing! Within maybe two minutes of slow drilling, I had drilled through the one inch of broken extractor!!! I then jumped up the 3/16" bit and went right through it again. Still in shock, I can't explain how crazy awesome that was. I then had no longer had a broken off extractor to deal with and could get back to dealing with getting the broken seized bolt out. And now I'm no longer worried about ever breaking an easy out or extractor again, knowing that these bits with cut through like drilling soft wood. Both bits are in great shape and show no wear. I would recommend these to anyone that needs to drill through crazy hard metal!

I snapped off a torx bolt in my chainsaw, then foolishly tried to remove it with a cheap easy-out, which only made it harder. Then I tried every other drill bit I could find, in every way. Slow speed, with oil, without oil, high speed, spent hours and got almost nowhere. I made a little progress with cobalt bits, but dulled out two of them and only got halfway through. Then I tried these solid carbide bits. Nice and slow, cut right through in 20 minutes. One negative -- I did break one of the carbide bits; more my fault, got impatient and pressed down a little too hard. But these bits saved my chain saw.

I bought this to drill holes to build racking from salvage galvanized 2x2 angle iron. Did 96 holes on my dad's drill press and it worked like a dream! The bit was definitely worn despite copious amounts of oil after that volume of work in a drill press. I also had great result using this it with my corded Makita drill in an SDS adapter (not in hammer mode) for pieces that wouldn't fit in the drill press. Use any household oil (I used mineral oil) to cool the work and the bit. With the drill set straight into the material and with good pressure, this bit will drill holes very nicely even with a corded drill. I would only use this in a cordless drill hand driver if the material was thin, such as metal studs or sheet metal. I could see the bit snapping from not being perpendicular to the work on heavier material and the user bending the bit as it bites. Not happened to me (yet). Definitely glad you get two bits per order, just in case.

If you are looking for an item like this then you found the right one here. The quality and craftsmanship of this item is far superior to many other items like this. I have looked around for this item and have found that this one is one of the best based upon quality, craftsmanship, price and ratings. I would highly recommend going business with this Vendor.

Excellent bit for hard material. Extremely sharp. Needs LESS pressure than regular bits. I broke part of a flute off with my first bit trying to drill a bearing cap grease hole. Less pressure, less speed, and less torque completed the hole with the next bit. I re-pointed and sharpened the broken bit with a diamond wheel to get it back in working order. BE CAREFUL with these bits! They have very specific uses -not general drilling- and do not tolerate misuse.