Here's some pictures of my finally-finished chairlift chair swing!
I had a local fabrication shop weld and powder-coat the 3" steel tubing frame to allow the chair to swing, built in three pieces to allow for transport and assembly. Toughest part was figuring out how to use the original cable clamp while permitting swinging in both x and y directions - I suppose I could have just forced the side-to side motion to be rigid, but for some reason was reluctant to take that shortcut.
Official color is "Chairlift Blue" even though actual chairlift chairs built this century all seem to be galvanized (Zinc-plated, silver/gray) instead of painted.
Total cost for fabrication and painting: $2,175. The frame is bolted to four concrete footings 10" dia. x 2 ft deep. I used a couple of raft straps to gradually lift the chair up onto the bushing that replicates the cable attachment point.
No safety bar on this (approx.) 1961 chair, might have to disinvite my one particular ski-buddy who annoyingly swings his skis while riding the lift. Greatest hazard of riding this chair-swing is from stray golf balls off the first tee, across the street.
Construction photos:
Two pillow-block bearings, plus the original cable clamp, well-greased to preserve the original old-chairlift riding experience of grease dripping onto ski pants.
Lifting up and securing the cross-bar was the toughest part... needed another, taller ladder.