So I was using a Titan Aero with an E3D heat block, random pack of Chinese nozzles and TH3D Tough from the heatbreak up. Until I went to change the nozzle to 0.6mm for a spool of wood filament. Then this happened:
So now I'm back to my stock Creality hotend.
Which is a better design structurally I think. In the E3D design the heatbreak walls have to be thin for thermal performance, but not to thin or it can't handle the structural stress. In Creality's the heatbreak doesn't handle the structural duties alone - the screws help handle the load. Similar to the Mosquito.
I can go a little faster now, but I miss the small retractions and linear advance on the Aero.