I have a piece of Peek tubing with an ID of .025" that I want to drill to .0492" with a depth of .48".

I've tried a few different bits, high speed steel with titanium-nitride and nitro-carburized finishes, and cobalt steel drills. The most luck I’ve had so far is using the high speed steel with TiN coating at about 5200 rpm. Even when using this set up, the drill bit seems to wander after already entering the ID and make a sub standard cut, often making a crooked cut.

I use air-cooling since my set-up doesn't allow for any liquid cooling/lubricants to be used.

Is there some way I can get more consistent results?

Thanks!