Any tips for widening the ebay exhaust mounting holes?
 

My ebay exhaust is on its way - I wondered if anyone had any tricks for widening the mounting holes in the stainless part that mounts to the cylinder. I know they have to be about a half inch.

I can get some tungsten carbide bits but this looks tricky on such a large existing hole. Those that simply cut it open at one end, what did you use?

A step bit like Rangerscott suggested or a thin cutoff blade on a grinder work great on stainless steel for cutting the ends open.

It's not that tricky to drill the existing holes. I widened mine with a cheap set of titanium coated bits from Harbor Freight. The real trick is to spin that bit slowly, lubricate the bit with cutting oil (or any kind of light oil), and step up the sizes. The number one cause of burned up bits is heat, and heat is caused by high speed, high pressure, and friction. So spin it slow, let the bit do the work, and remember that you can never have too much lube ;)

Thanks all - very useful.

Nip the ends out. Takes five minutes with a Dremel, tops. Cuts fast with little effort. I chose this method as it will allow it to stay centered as it expands and contracts in the exhaust port. Done two this way, zero issues.

That is the way I recommend doing it...ARH

I didn't think of the dremel! What bit did you use? I'll need to get one as I don't have any cutting wheels or anything like that, just various grinding stones and sanders.

I used the little cutting wheels. Four little cuts. They're super cheap at any Lowes, etc....

I did it with a bench grinder, using the edge of the stone.

I did it the 2LZ way with cutoff wheel. Took all of five minutes