Many articles I’ve written about tools revolve around some more complicated, some might say exotic, items.
Today, we’re going to deviate and talk about something that is seemingly simple—a specialty drill bit.
Maybe it can help some of you with what may seem on the surface 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 a steering column.
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 of a problem because I could anneal it after trimming it to shape.
After annealing 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 in my tool chests. I tried to drill the hole with three different drills—a conventional 3/8-inch Makita variable-speed electric, a Mac Tools air-powered drill, and a ½-inch Makita hammer drill.
I spent at least two hours on it. Nothing worked.
So 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, he annealed it with a TIG welder.
Once 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 machine shops and after hearing the story, no one wanted to touch it.
After that, my options were to package the part and send it to a specialty shop for EDM (Electrical Discharge Machining) to accurately arc-machine the hole for $200, or to buy different 1/8-inch drill bits and try again myself (using each of the three drills used before).
After thinking about it, I figured I didn’t have much to lose by trying different drill bits.
The first bit I tried was a fresh, sharp high-speed steel drill bit. It didn’t even scratch the surface.
The second bit I tried was titanium-coated. The guy at the tool supply shop said it would absolutely, positively, 100-percent drill through hardened steel. It even said so on the package. Both the tool guy and the package were wrong. It didn’t work.
I searched the internet for answers. 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, that didn’t work either.
Back to the internet.
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. After all, a hammer drill provides plenty of grunt. I bought and tried the fancy hammer drill bit. And it didn’t do any better than the others. Obviously, brute force wasn’t going to work either.
I was frustrated and it looked like the EDM job was my only option.
Stumbling on the Solution
Finally, while rummaging through various drill bits at Home Depot, I spied a goofy-looking one with no flutes that is designed to drill through granite tile.
I didn’t think it had any chance of ever 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 strang-looking drill bit went through hardened steel like butter. It cost me about $13.
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.