AndyMark 1/2" churro tube .00535 in^4 [Solidworks] VexPro 1/2" round tube .00570 in^4 [Shigley 8th ed. Table A-18] 1/2" round shaft w/ 1/8" keyway .00570 in^4 [Solidworks] 1/2" round bar .00614 in^4 [Shigley 8th ed. Table A-18] 1/2" hex bar .00752 in^4 [Wikipedia]