Pulled from real product images (via browser). What's STOCK vs CUSTOM, with the specs + the catch on each.
The real in-place rig: a stationary pulley bolted to the angle + a floating pulley on the spring end, cable routed through both (2:1 block-and-tackle), safety cable through the spring. Pulleys mount right on the angle brace — your punch-angle standoff.
⚠ Resi sheaves = 100–200 lb; your coupling is ~800–1,700 lb → same rig, HEAVY commercial pulleys. Cable routes off these to the drum.
Cast steel disc — center hub (bearing) + spoke cut-outs + bolt holes. The rotating end the slat curtain coils onto.
Sizes ~9.5″ (self-storage) → 12″+ (commercial). The drive ring clamps the barrel pipe near this.
Side-mounts on the tube; disengage it and the chain hoist still lifts. Sits far off the wall on your standoff bracket.
⚠ 8500 needs the monitor-cable adapter (S2) + a routed emergency release (cord + hooks to the side). A commercial jackshaft skips the S2 hack.
Formed plate: center bearing (tube shaft rotates in it) + slotted mounting flange that bolts to structure.
Proof your top counterbalance is a standard sectional torsion setup — bearing plates + tube + springs + drums — just with bigger commercial springs (more spacing, same mechanics).
Grooved cast drums that mount on the torsion tube and reel the cable. Stock + cheap (~$13–18/pair) — 400-8 / 400-96 / 400-144 by door height.
⚠ Stock ones mount by set-screw → use KEYED for your ~800–1,700 lb coupling torque. Drum Ø is your tuning knob: bigger = lower cable tension + more groove capacity.
Large-diameter cast spoked drum with a grooved rim. Real, available (high-lift) — just bigger than the standard little drum.
This solves the load: bigger Ø = lower cable tension (T = torque ÷ radius) + more groove capacity for the barrel's turns. Use this Ø on the coupling.
Grooved drum on a shaft end, bolted to a steel flag bracket at the jamb corner, cable wrapping it (from a low-headroom setup).
Option B for grabbing the barrel: bolt a drum to the barrel's rotating end casting + a bracket → positive drive, no clamp-slip. Needs a boltable rotating face (vs the split-clamp ring where it's a smooth sealed pipe).
Small exposed barrel — no big hood, light slat curtain, little operator on the end. Self-storage / light commercial.
Easy win: the barrel end is open and reachable → clamp/bolt it with no teardown. Light kit = grab the end, resi springs (1.75–2″), jackshaft drive.