Adrian's PTFE LIned Nozzle

Adrian posted a new plan for a geared extruder nozzle withPTFE lined PEEK thermal insulation and brass nozzle a couple of days ago. This looks easier to make since it doesn't involve tapping threads. I'm wondering if the PEEK over brass joint would be prone to leaks since the plastic would expand at high temperature. The PTFE tubing would expand inside the brass so perhaps that's enough to seal the joint.

Yeah, as long as the coefficient of expansion of the outer piece is lower than the COE of the inner piece, the increase in temperature will cause the innner piece to seal itself against the outer piece. The COE of the plastic seems about four times that of the metal.
[www.engineershandbook.com]
[en.wikipedia.org]

i like where he is going with that idea, the less you have to thread metal into plastic the better i think. on the other side though it dose seem to involve a more intricate design to fabricate. no more so than the big head from makergear i would think though

i do like it though