Bagman2524:
So you have 1.66” for an o.d. on the 1.25” pipe posts; and 1.38” i.d and .14” wall thk. for the sch. 40 pipe; and 1.278” i.d. and .191” wall thk. for the sch. 80 pipe. Now, look for round mechanical tubing (at most steel supply outfits), various material specs., with a slightly larger i.d. and a comparable wall thk. for either one of the pipe posts, and you’ll be in the right ball park. Maybe 2.125” dia. w/ .188 wall thk. and 1.75” i.d.; and 2.25” dia. w/ .25” wall thk. and 1.75’ i.d., should get you started. The sleeve gets welded to some sort of a base pl. with A.B’s. and it might be 8” long, and is drilled for a through bolt on its neutral axis, w.r.t. its bending stresses (that is parallel to the direction of the railing). The sleeve could also be embedded in the conc. The annular space btwn. the two tends to fill with junk and rust, so you have to deal with that.