Reporting back: @Barryg41 suggests a torque of 1.15Nm,
and it got a thumbs up from @JonRaymond. Though the discussion wasn’t specifically about H2D, is it reasonable to suppose the same spec would apply?
For comparison, Grok recommends a lower torque:
For safety in 3D printer applications with soft materials like aluminum, aim for the lower end (e.g., 0.5-1 Nm) and consider using threadlocker like purple Loctite for vibration resistance.
Which raises a good point: in most cases, are we not threading directly into aluminum on the H2D hotend? i.e. we should account for the softer material? Or, if not, what material are we threading into? I haven’t taken an H2D hotend apart, and I didn’t pay enough attention when last I was tightening the screws to properly notice. The whole assembly is put together so tightly I’m not sure I even could notice just from looking at it in its fully assembled state. No obvious way to probe the screw holes with magnets either without possible confounding from nearby parts.