[TowerTalk] Joining Boom together

[Denis Coolican]

I would think that your 2.5 inch Al tubing has a 0.65 wall which would make the inside diameter 2.370 inch. Now 2 inch sched 40 has an OD of 2.375 so that is why it does not fit in the 2.370 inch hole. 
I would suggest you take your 2 inch sched 40 Al pipe and turn off .010 inch which would leave you with an OD of 2.355.  If you turned off .005 instead you would have an OD of 2.365 inch. 
Things would fit nice and snug. Turn it off in a metal lathe.

Denis ve6aq