Looks interesting,
Have you seen this though ?
[
www.thingiverse.com]
I like the quick release/lock.
As for the hot end,
I've made my own, bronze bar turned down for glass fibre wrapped nichrome wire, M6 inside thread, a small hole coaxial with the M6 thread for a 100k ntc thermistor and a brass bolt machined to a pointed end, 2mm drilled + the very end drilled to .4mm. this butts on to a SS M6 threaded rod with about 6mm thread on each end and a turned down section between for about 8mm length for the thermal insulation. (Stainless steel is a really bad thermal conductor compared with most metals.
On the top end, the SS threads into some hex aluminium shank that I cut an M6 thread into the inside of, I cut a fine M10 thread onto the outside and this screws into a piece of aluminium bar stock that I have fitted to my delta effector. Seems to work reliably, though I'm still working on my firmware as I designed my own custom ARM Cortex based PCB some 4-5 years ago, I'm only just finishing it off now after a break of 4 years!
My hot end isn't completely refined yet, but It looks better to me than the J types I've seen on line as it's smaller. Less thermal mass and area has to be good!
Graham.
My CNC/extruder creation: [
grael-minifactory.blogspot.com]
