You are doing this to promote adhesion for the epoxy, correct? What size hole are you drilling? Something you may want to consider is running an undersize tap through such that it just forms a slight groove in the wall. That groove will provide a mechanical lock for the epoxy so that it will take significantly more force to shear the tube from the hole. We do this all the time when pillar bedding rifle stocks and its a common assembly technique in industry. The trick is finding a tap that is sized for what you need, though it isn't hard to grind one undersize or single point it in a milling machine. You still want to have the hole surface prepped properly using the hone or sand paper, but I always do the tap when I can for peace of mind.