Drilling Airholes Into TBC-2 RBA

[iz2sick]

I drilled out two airholes in my TBC-2 rba today and it works great. My question is though, how does one smooth out the airholes after drilling? When I first drilled them out, the metal had that punctured look where the drill came out.

What I did was started the drilling on the stock airhole and just drilled straight through to the other side. So now, on the inside of the first hole, the metal has sharp protrusions. The same happened to the new hole except it was on the exterior of the cap. So I took a larger drill bit and lightly started drilling that new hole from the outside. I managed to get it to go down so no more sharp edges, but it looks like crap now. I can't do anything about the one on the inside of the original hole.

I'm not a handy guy, so I would like some advice here. I appreciate any help. I'll definitely be drilling holes from now on when needed so I want to learn how to do it right.

 

[tmcase]

To smooth out the hole on the inside use a dremel with a grinder bit. I'm not sure if that is what you are asking about but if so then a dremel will work.

 

[sawlight]

A "half round" needle file will work inside, and a full round needle file can work on the outside. Gently rub the half round inside until it's smooth.
On the outside, stick the tip of the round file in the hole and twist it, you may have to hold it at an angle and work around the outside of the hole, careful to not make it larger.
I have a full set of these that I use, 1/4" 82 DEGREE HSS SINGLE FLUTE COUNTERSINK 3/16" SHANK on eBay! which is really the proper way to do the outside.