Tube squaring antics

One remaining nagging point about this kit is that none of the tube ends are even/square.  I think the longest these 7.5" tubes are manufactured is 60" so I would have guessed that at least ONE of the four ends would be square and usable as a reference for the other ends -- alas this was not the case.

     This unevenness looks bad and increases the chance than the payload and sustainer won't distribute loads evenly and worsen the chances of buckling during flight.  Since these tubes are comparatively large I had to be clever in squaring them up.  I tried several things but in the end I settled on an L-square ruler and spirit level (both of those have proven so handy during this build!). I verified that my kitchen countertop is perfectly even with the level then laid the 20" payload tube horizontally on that surface.  I then aligned the long edge of the L-square along the top of the tube so the short edge dangled downward.   This allowed me to find/mark high spots on the tube edge and iteratively sand down those spots and recheck.  When one end was even I repeated this technique on the other end.  

     Once that tube was square I used it and the coupler tube to square off the sustainer tube which was WAY uneven.  Duh.  In any even all four tube ends and the motor tube end are now square and looking nice.