I've been pretty busy with work, but I'm taking some time this weekend to put together the E3D hotend.
Getting the thermistor in was rather fiddly, making sure the sleeving didn't slip out. My first attempt didn't go so well - you can see one of the bare wires:
I retried and got this, which looks acceptable:
Assembling the rest of the E3D was pretty easy, but mounting it showed a bigger problem: The E3D mount is a lot bigger than the J-head: 16mm wide with 12mm groove width, where the J-head is 10mm wide with 8.5mm groove. The hole in the extruder is 10.5mm.
I thought I had done my research properly, and indeed everything I find says you can mount an E3D on a Wade's Extruder. The reprap.org Wade's extruder page makes it sound like it's a 16mm hole, so why is mine different? Is mine a weird mutation on Wade's? I got it from reprap-fab.org, but when I go there now, a) my order is no longer visible, and b) the item with the same name is entirely different - it has a similar-looking hotend, though. I don't think this is an early J-head after all, but some other piece
Regardless of how this came to be, I now have a crappy hotend that fits my extruder and a shiny new hotend that doesn't. This leaves me with three choices:
1) Try to get/make an adapter (but that could make the assembly too long for the fan duct +Thomas Riedl so nicely printed for me).
2) Get (or have someone print) a new extruder (part).
3) Get a hotend that fits the existing extruder.