I think I stumbled onto a way to make a true “one machine to rule them all” for tiny home gyms, and I’m buzzing to sanity-check it with folks who mod their gear.

Concept: a rack with dual weight stacks hidden in the uprights and a quick-route “cable manifold” that lets you click between modes without rethreading. The same stacks would drive:

Belt squat/Belt deadlift
Low row/Lat pulldown
Jammer arms (lever press/row/landmine-style)
Assisted pull-up/dip
Smith-guided bar (carriage locks onto uprights)
Hack squat/leg press via fold-down footplate + rolling seat
High/low adjustable pulleys for everything else

Key twists I haven’t seen done cleanly:

A fast mechanical selector to swap 1:1, 2:1, and 4:1 ratios so you can go heavy for compounds, then flip to finer increments for isolation without swapping cables.
A take-up system to kill slack when switching stations (thinking constant-force spring or a tiny counterweight sled inside the upright).
A “stack combiner” that can sum both stacks for heavy moves or separate them for unilateral work without cross-talk.

Questions for the hive mind:
1) Variable ratio selector: Is there an off-the-shelf flip-block/cam solution that’s safe under ₄₀₀-600 lb equivalent, or is this bespoke? Any sketches or parts you’d recommend?
2) Cable and sheaves: Anyone run Dyneema/Amsteel in a home gym? What diameter line and pulley size kept friction and wear low while staying quiet?
3) Jammer arm drive: Best attachment point to keep the force vector clean through the arc? Yoke both sides of the arm vs. capstan wrap vs. offset tab?
4) Stack combiner: Equalizer pulley “Y” vs. dogbone yoke-how do you prevent one side from stealing travel on unilateral work?
5) Slack/tension: Favorite low-noise take-up approaches that won’t fight you at end range?
6) Safety: Passive failsafes if a pin slips or line fails-ratchet pawls on sleds, friction dampers, UHMW “catchers”?
7) Footprint: Anyone get a fold-down seat/footplate to clear <30″ depth and still feel solid under heavy hack/leg press?

If you’ve built or seen anything similar, I’d love pics, part lists, or “don’t do this” lessons. If this is viable, we could have a blueprint for a quiet, apartment-friendly, truly multi-use machine without the usual compromises.