Nozzle Part 2

Work continues on the nozzles,  these are almost complete.  All that remains to be done is to thread the base to 1/4"-28.  I had made 8 blanks, so I drilled 3 to .5mm (0.0197") and 3 to .3mm (0.0118"), leaving 2 "blank".  I think I'll try a little smaller at some point, perhaps .25mm or .2mm but I want to get the larger sizes working reliably first.  I might also want to attempt to get a smaller filament to make such a small nozzle size easier.

These are the thermal break tubes.  303 stainless steel was used because it machines so well while retaining much of the qualities of stainless steel, such as a relatively poor heat conductivity.  The diameter is reduced right after it connects to the heater block.  This will hopefully further reduce the amount of heat transferred upwards.  The wall thickness here is ~.025".  The bore was reamed to size for the smoothest finish I could get.  The upper portion will contact the aluminum heatsink. The only thing left to do on these is to cut the wrench flats on the largest diameter section.  

These are the blanks for the heatsinks.  1" thick, and 40mm square to match the fan.  There are a bunch of operations to do on these before they are ready to use as a heatsink.  The altered slightly from pictured earlier.  Instead of a separate duct part, I've made the heatsink match the fan size, one less part, and it makes the whole thing smaller.  I'm still not 100% that this arrangement will provide enough cooling, but it's worth a shot.  With any luck I can get these and the heater blocks done by the end of the weekend.  PLA has been ordered, but has not yet arrived, and I have pretty much finalized the extruder drive design.  

As is often the case when building things, I get ideas for how I can make it better.  Thinking about the construction of the nozzle, it occurs to me that given the right sequence of draw dies, one could easily draw cartridge brass to the right shape, without machining.  The wall would be no thicker than the original material, so the reduction would be very small.  A flange could also be molded on the end to attach with a flare style nut, perhaps even using an off the shelf fitting.  Something to think about for next time.