I've used the brass tube technique in many places. You really don't even need a drill, as long as your tube is sharp. In my experience a sharpened brass tube will make a hole about 10times cleaner than any drill bit too. Its a very precise hole. I've done holes up to 1/2"... A tube will not leave any jagged edges, will not tear the wood as it exits, none of that.... and.... the coolest thing... you can angle your hole as you need... as in push-rod exits... very very cleanly. Most everyone has a tube sitting around in a junk space... I think those who haven't tried it really should... you'd be amazed. Be sure to sharpen the inside with an X-acto, just stick the blade inside, spin the tube so your cutting the inside... it doesn't hurt to hit the outside with a little sandpaper, but thats really not necessary. Find a scrap piece of balsa and check it out.. then cut some angle holes too... I wouldn't be without my tubes for making holes in balsa... you can get some serious angles too.. I have found with the bigger diameter holes.. as someone mentioned.... just dremel some teeth into your tube... just put the tube to the wood and spin in.. in thin balsa, you can make a hole quicker then you can grab a drill... in thicker balsa.. you can make a hole quicker then you can set-up your drill... I'm obviouly a fan of tube-cutting balsa...its one of the best tricks I've learned over the years.