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 (5/32")

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.

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 own several full indexes of drill bits, most are high end, American made. I was trying to drill a 3/16" hole in the release plate on a S10 parking brake in my 1939 ford. Not one of my bits would even mark the surface. Ordered 2 solid carbide bits from Mars and drilled the hole with one bit. It wasn't easy but got the job done. Pricey to me at $34 for 2 but it worked.

I needed to drill a 5/32” hole through a piece of 1/8” very hard stainless. My first attempt was with high quality cobalt steel drill bits.. I used a drill press and oil with the slowest speed on my drill press. Effort was made to keep the bits as cool as possible but after ruining 5 identical bits with little progress it became clear that something else needed to be tried. This bit did the job easily but I did take the precaution of drilling slowly with a drill press. I stopped several times to clean away the cuttings and kept the bit oiled. I did examine the tip of the bit with 20x magnification afterwards and found two microscopic chips in the cutting edges of the blade. This should not affect the usefulness of the bit. The bits may seem to be expensive but nothing else could get the job done. I am completely satisfied with these bits.

Had to drill 1/4” steel on a boat lift I-beam. Had previously spent hours trying (unsuccessfully) with so-called “hi-speed” bits. Following some You-Tubers advice, I drilled 1/8” pilot holes, followed by 3/16”. As this project was in the boat slip, over the water, I had to use a hand drill (impossible to use a drill press). I used some spray silicone lube as coolant/cutting oil.Worked beautifully, drilled 12 holes in just a few minutes. As advised, these are brittle, and I did shatter two of the bits during drilling. But as I was basically balancing on a 4” wide beam (over water) while holding the drill in one hand and the beam in the other, a little wobbling was not surprising, and that’s how I broke the bits.But I would definitely buy them again. Under normal circumstances (two feet on solid ground), and for sure in a press, I think they’d be great.

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!

Junk used mag press 700rpm volume didn't go 1/4 before dulling lowes Dewalt bits are equivalent

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.