This will do

[opabinia]

until bottleimp sends his extra-eeevil rotating version:

Thanks to industrialsteve, the skilled machinist.

The 1" steel pipe is center-suspended, meaning that any asymmetrical pull will destabilize the movement. There will be no cheating on these pull-ups.

That rope is theoretically strong enough to hold me up single-stranded. I doubled it over, just in case, because plenty of tensile strength is lost in knots and such. Still looks kinda thin; that gives me extra motivation to go slow and tight. Fortunately, this is a grind move, not a ballistic (pronounced "potentially rope-snapping") drill.

[...]

Woo!