Even when one has removed the burrs from the holes on the inside of the tube they are still very sharp. I think it was TKO that suggested a Dremel ball bit, not the one pictured, but you get the drift, manipulated inside the tube till you can get the shaft out of the hole then twisted by hand to break the corners of the holes. A small screw with a countersink head and a piece of 400 or so sandpaper taped or glued to prevent slippage turned by hand or with a drill will do the same. I slacked and did not take the time to do this on my last project cuz I was in a hurry for some unknown reason so got the deserved results of the dreadful slow leakage of pressure from the tube. So being in such a hurry I just left it lay on the floor for the last two months while I pondered the reason for my existence. ;^)
I used to have a life. But now I have the forum. I am a sick man?