Many of the articles I’ve penned tend discuss some complex (or once in a while, exotic) items. This time around I’m going to deviate a bit and talk about something that is seemingly simple – a specialty drill bit. I’ll share it as a personal experience and maybe it can help some of you out with what on the surface seems like a simple dilemma:
I needed to drill a hole through hardened steel – in this case, the piece of steel was what was left of the lower shift lever on the steering column for a Nova I was working on. The steering column was a three-on-the-tree assembly converted to a floor shift application with a new bowl, but parts of the shifter linkage remained. The idea here was to trim the remnants off and then drill a hole in what was left so that it could be safety wired shut. I knew going in that by cutting (with a cut-off wheel) and grinding the linkage it would work harden. That didn’t seem to be too big a problem because I could anneal it after it was trimmed to shape.
After I annealed the piece, I tried to drill a 1/8-inch hole in the linkage with a conventional high-speed drill bit. In the process, I tried pretty much everything reasonable I had in my tool chests. I attempted to drill the hole with three different drills – a conventional 3/8-inch Makita variable speed electric, a Mac Tools air powered drill and finally, a ½-inch Makita hammer drill. I’ll bet I spent at least two hours on it. Nothing worked.
Because of that, I went to a local machinist. He dragged a file across the linkage and quickly came to the conclusion that the steel was actually hardened (and not so much by me). Next up he annealed it with a TIG welder. Once it cooled, the column shaft was clamped into the vise of a Bridgeport mill. The end result (following several attempts – all with more annealing) was a small dent in the hardened shift lever using a 1/8-inch bit. That “dent” measured approximately 0.010-inch deep. It wasn’t looking good.
I checked with a couple of other local machine shops and once they heard the story, they didn’t want to touch it. After that, my option was to package up the part and send it to a specialty shop three hours away and EDM (Electrical Discharge Machining – where the hole is accurately arc machined) the hole for $200 or buy some different 1/8-inch drill bits and try again myself (using each of the three drills used before).
I thought about it a bit and figured I didn’t much to lose by trying some different drill bits. The first bit I tried was a fresh, sharp high-speed steel drill bit. It didn’t work. It didn’t even scratch the surface.
The next bit I tried was a Titanium coated example. The guy at the tool supply shop said it would absolutely, positively, 100% drill through hardened steel. It even said so on the package. The tool guy and the package were both wrong. It didn’t work.
Fair enough, so I searched the Internet for an answer. I found a bulletin board post where someone said a masonry drill bit would work perfectly for my dilemma. I bought a masonry bit. Unfortunately, it too didn’t work.
Back to the world wide web. I found another bulletin board post where someone suggested I use a drill bit designed to work on a hammer drill. Since I had a hammer drill, I figured I had nothing to lose. I was certain this would work. The guy at the tool supply shop agreed. Afterall, a hammer drill provides plenty of grunt. I bought and tried the fancy hammer drill bit. The truth is, it didn’t do any better than the others. Obviously brute force didn’t work.
I was starting to get frustrated and it looked like the EDM job was my only option.
Finally, while rummaging through various drill bits at (of all places) the local Home Depot, I spied a goofy looking example. It has no flutes and it is designed to drill through granite tile. I didn’t think it had any chance (ever) of going through hardened steel, but I didn’t have anything to lose. I tried it with the 3/8-inch drive variable speed drill (on low). And guess what? That strange looking drill bit went through hardened steel like butter. It cost me approximately $13.
The bottom line here is, I highly recommend you try one if you have to drill through hardened steel! For a closer look at the drill bit selection I went through in the process, check out the accompanying photos.
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This is where the saga began. I removed and sliced off several pieces of the shift linkage (with the column out of the car) and what remained of this three-on-the-tree steering column setup is what I was attempting to drill through. You’d think that would be a piece of cake! 
I have six different drills in my tool collection and I used three of them on the little project. I thought for sure if all else failed, the brute force Makita hammer drill would burn through the steel piece. After all, I was only drilling a 1/8-inch diameter hole. 
Here’s a collection of the 1/8-inch drill bits I tried that didn’t work. From left to right: A fresh, sharp high-speed steel bit, a titanium coated drill bit “designed to go through hardened steel”, a masonry bit and finally, a fancy hammer drill bit. 
This was the solution: The funny looking 1/8-inch bit is actually intended to drill through granite tile. And boy does it ever slice through hardened steel (using the variable speed 3/8-inch drive drill)! 
Here’s a close up. Note that it has no flutes. 
This is the entire purpose of drilling the hole: I simply wanted to safety wire the remnants of the shifter linkage to the column so that the steering column bowl didn’t flop around. Seemed like a simple enough task in the beginning!