Antique & Classic Cars Blog

Conventional wisdom holds that Triumph’s TR6 was built in England. New evidence suggests otherwise–or at least that the rear bumper bolts were not. Given their insane hardness, a more likely source is Krypton. (You can imagine how much force someone from the Superman or Superdotter family could apply with a wrench, or heaven forbid, a breaker bar.)

So some of this Kryptonese hardware got into the rear bumper on my car and, outrageously, rusted. When I put a wrench on the two bolts in question, they snapped off.

Drilling out a broken bolt seemed like a useful blog post. You file the break point flat, rap a center punch in the middle, and start a metal drill bit in the indentation, running it all the way through the remaining bolt portion and out the bottom, right down the center. If you’re a little off, you can angle the drill bit back toward center and correct the offset. Run a few increasingly larger bits through until you’ve drilled out just about everthing except the threads remaining in the bolt hole. Take a fine-pointed punch, stick it between the clinging threads and hole and give it a rap. Gradually, you can peel the threads out in a coil.

But NOT if the bolt is from Krypton. I managed to get some combination of my old bits much of the way through. Then no more. Bought some regular high speed bits. Krypton laughed. Returned them and bought a set of titanium bits. Krypton shook its head.

The titanium were not my first choice, though everyone knows titanium is nearly as tough as Kryptonite. So finally I bought some individual cobalt bits, which I’ve had luck with in the past. One of these did some damage, then seemed to go dull.

The hole is pretty well centered now. Just need to get through the bottom of the bolt and run a couple more bits through it. But a morning’s worth of effort hasn’t put a bit all the way through. It will be a disappointment for me if I have to take a simple drill-out to a machine shop, but when you’re dealing with extra-planetary stuff, that’s what it might take. If the shop that advertises “we can deal with the hardest metals” has a stocky guy with wavy black hair and glasses, who grins a little when I describe the problem, I’ll know I’ve found the right place.

This entry was posted on Wednesday, February 13th, 2008 at 2:25 pm and is filed under Car parts. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.