Drilling Hardened Steel With Masonry Bits - Not A Lifehack

A bit of a shorter video this week. Gearing up to do a long build series (something to the tune of 10 weeks/videos) so a short fun video like this is all I could get out this week. Stay tuned. Cheers EDIT 22-5-2023: I think I might have overlooked a discussion on regrinding the tip, maybe better for drilling steel. Seems like other people have faired better than me in doing so. I thought I could get away with using the standard grind, which might not have been the best assumption. Definitely something useful here, but best used in specific situations.

You definitely need to sharpen the end

I have used one running backwards to drill out a broken tap - had to re grind the carbide tip so the cutting edges were on the opposite side . Also don’t throw away your used parting tool inserts , you can braze them to a steel rod to make small drills - takes a bit of grinding but you essentially create a spade bit type of drill .

Masonry bits don't really "cut" as such - it's the impact that creates the hole, and the rotation between impacts serves to keep the hole round. Basically a rotating chisel. So it'll definitely need grinding to cut steel!

Done this for years for hardened spring steel. The trick to not chipping the carbide is go slow when you are breaking through the back side. I've found , that's when the chipping usually occurs. Obviously not for precision location holes, but on clearance holes for bolting things together, hard to beat the price.

I have experience with this, I did my apprenticeship in a toolroom making press tooling for sheet metal parts. In a few situations wee needed to drill through dies after they'd been hardened, start holes for wire EDM modifications etc. So it was usually hardened K110 or Calmax which is pretty tough stuff. Solid carbide drill, yes they could do it but tended to shatter after a while because of the chatter and forces involved. The masonry drill was perfect for this because of the soft steel shank which let it absorb vibes and bend without shattering. The key though is sharpening the cutting edges with a fine grit diamond grinding wheel. Then it works perfectly for numerous uses. Also have to keep it cool with lubricant or else the solder melts and the carbide goes bye-bye. You can do a starting spot with the solid carbide drill.

If you want to go through hard steel, not quite as hard as HSS or tool steel, you can grind a standard drill bit to have a very shallow angle on it. Almost a flat bottom drill but with just a slight tip angle. And I’ve actually drilled through some hard metal with cheap drill bits and it actually works really well. The hardest part, no pun intended, is getting the drill started without it walking.

I keep a bunch of masonry bits around. I regrind the carbide tip for cutting metal and they work great. Not only can they stand up against harder materials, but they are essentially a spade drill, so they don't wander like twist drills.

Thank you for your video, I came on here looking for help I spent 3 1/2 hours trying to drill through hardened steel I got about half way through it was only 1/8 thick. My hands were starting to get blisters that is when I found you and your video which saved my hands. I had high speed metal bits broke two of them I knew I had 3 masonry bits the same size but used so I finished the other half in one hour instead of 3 1/2 hours and if those bits were new who knows how short the time would have been. I got my one whole drilled and saved me from going to the big box hardware store. So it does work and when that tip is gone your out of luck I am glad I had three used ones to finish. Thank you again. Don

I've ground a cutting edge on the drill with a green stone on my bench grinder in the past... worked reasonably well for the one hole I needed.

What a wonderful tip! Used an 11mm concrete drill to widen the neck of an impact socket just enough to accommodate the long bolt I was trying to get out. Great!

Depending on the part being drilled you can also anneal it in the drilled area if that isn't an issue. You can typically use regular hss drills doing that. We used to anneal induction bar for drilling back in the day before buying proper carbide drills.

i have successfully done this many times. My late father in law, an experienced machinist, showed me how. They do it in the work shop for small jobs where the right sized bit is not on hand. The crucial thing is sharpening the carbide tip, to give a workable relief angle. Pretty easy to do. I have drilled stainless and hardened steel (old files). Also, using cutting lubricant/coolant helps to prevent overheating and failure of the drill bit.

Decades ago, I used a drill bit like this to drill a hole in a piece of hardened drill because the only drill of this size had died in combat. As a coolant, I had only water available, drilled with an ordinary market drill. In some situations, even using a nail as a drill bit can help get the job done.

It works fine if you sharpen the carbide tip a bit first with a diamond wheel or file, it will last many holes then.And a dab of cooling oil wont hurt either :) The only thing you need to watch out for is heating it up to he point were the brasing melts!

While I haven't reground the tip before, typically a masonry bit is my home-shop "emergency dill" method. If I accidentally overheat what I'm working on and it becomes annealed, or if I'm drilling something hard, the next step is a Carbide Masonry bit. I have however, taken a little time to ensure that I have decent ones (sometimes $5-10 each). They work decently, however as noted, they don't make PRECISION holes.

That's awesome I was trying to drill through hardened steel and I just couldn't do it without buying carbine drill bit I just couldn't do it came across your video and was able to finish a job thank you so much

I've used masonry bits on hardened steel several times. When necessary, I use a center punch first to keep the bit from walking.

I started a project needing to bore through what wasn't really hard steel but it quickly dulled the carbide bits I had. Most of the whole set since I varied the bits I would use to size up to the hole. After one round of dulling the factory sharpening and another of dulling my own sharpening, which happened much faster than the factory sharpening, I decided to use the half inch masonry bit I had left over from a one off job I did for someone. After seeing how much better that worked, I bought a pack of five eighth inch better quality carbide bits and got through the remaining four fifths of the drilling part of that project in the time I spent on the first fifth. Masonry bits don't come in a very wide range of sizes, but if someone wants to compensate for the cost of drill bits with their time, planning a project around the size of hole you're going to get with a masonry bit, is worth it.

To stat a hole use a small bullnose grinding stone and create a small dent so the drill will follow in as when you do a center punch