Hey Guys,

I recently received a catback exhaust, and the flanges that bolt up to the stock cat have bolt holes too small to fit the cat's bolts.

I tried drilling the holes out using high speed steel and also titanium coated bits with a hand drill, but failed pretty spectacularly. Both bits made some progress, but ultimately broke, even though they were only the next 1/64" size larger than the existing hole. With my car in pieces, my only options are to wait for them to ship me a replacement with correctly-sized holes, or get the holes drilled out about 0.1". Since the car is in pieces and is my daily driver, waiting means I'll have to pick up a rental car or something, which I'm in no mood to do.

So I'm trying to plan my attack for tomorrow. Any ideas on a place that may be open on a Sunday capable of drilling this midpipe? There are a couple generic tire/exhaust/brake places open, but I don't know if they'll be able to do it.

 

machine shop. Likely closed on weekends.

Maybe something like uhaul? They have to drill into frames in order to install hitches.

 

You can try drilling them again, but this time use some sort of lubricant on the bits continously and stopping to let the bits cool down.

 

Could you use thinner bolts from your auto parts store?

 

Last 2 suggestions sound line winners. P)

In fact the smaller diameter bolts should work fine since you just need to clamp the exhaust pieces together snug, I doubt slightly smaller bolts would be a problem.

 

A reamer drill bit works best when you want to make holes bigger in thick sheets of metal. You will need a "tapered reamer bit" Use lots of taping fluid.

Normal drill bits tend to break when you try to drill a bigger hole in thick metal

 

take off the cat and bang out the stock studs, then use a nut and bolt to attach it. probably save you a lot of time!

 

When I put my BR catback on, I stripped one of my factory bolts out so I just used one of the factory bolts and one longer smaller grade 8 steel bolt with a lock washer and nut, and worked like a champ.

 

Cobalt drill bits will get the job done, mcmastercarr.com granger.com or any other place.

and also remember to use cutting fluid this will help keep the metal cool and the bit wont go dull,,,, you also need to do it a low speeds do not go fast with the drill

 

what exhaust is this, may i ask?

 

Thanks for all of the suggestions.

I was able to get the holes drilled out using a standard titanium-coated bit. I just let the bit run really slow, maybe 100RPM, and applied lots of pressure. All I had around for lubrication was WD40, but it seemed to work OK in a pinch. It took a few hours, but it got done. Now it's all buttoned up and ready for a couple test drives.

endGameXIII: I'd rather not say at this time, as I've been working with the company through a number of issues, including this one. I'll post a review of the exhaust with all the details once I'm certain everything is installed correctly.

 

Cutting oil is the **** for this...
For the average guy, a 10 dollar bottle of cutting oil will last 20 years.