Talk:Geared extruder nozzle
is there a reason the teflon to brass interface is an M7 thread instead of an M6 thread? people already need an M6 tap and die to make the tip and heater block; why complicate it with a weird rare thread?
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Jkeegan 22:41, 8 March 2011 (UTC) - In the push-fit variation, the heater block has a notch cut in it, but doesn't have a hole drilled through the side for a bolt/nut to tighten it. Isn't that missing?
Reifsnyderb- The heater block is pressed into place. The hole, with the slit, has a slightly smaller ID than the nozzle. So, it is basically held on due to the friction between the two parts. No bolt, screw, etc., is needed to tighten it.
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Reifsnyderb- In the original variation, the M7x1 thread interface between the PTFE and brass nozzle can be skipped. If it is not threaded, the tension created by the threaded rods holding the nozzle in place is enough to hold it together without leaking. Without the M7x1 threads, the PTFE is much stronger and is less prone to break.
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Jkeegan 18:00, 9 December 2011 (UTC) - Ok I have another question (on the first design, with the threaded PTFE). I don't understand why the 10mm diameter hole in the PEEK block is drilled down 7mm deep, when the 10mm diameter flange on the nozzle is only 2.5mm thick.. Doesn't that mean that the nozzle will NOT be held up tight by the PEEK block? I was under the impression that that was the entire point? I expected the 10mm diameter hole to go 2.5mm deep, and then for the rest of the hole to be 8mm diameter. It seems that this design, as documented here, would have the flange reach 2.5mm down into the hole, but not actually rest upon anything (since the PTFE would press up against the PEEK block), then there's a 4.5 gap of air inside the PEEK block around the nozzle, then the 8mm barrel would fit snug in the 8mm hole. But that would seem to put tension on the threads in the PTFE to hold onto the barrel? Is this intentional? Am I missing something? Thanks ahead of time for any insight!
Jkeegan 12:07, 11 December 2011 (UTC) - Ahhh, never mind - I see my mistake now. I had the PEEK block upside down. Despite having read the page repeatedly about half a year ago, I forgot the following paragraph, right from the page: "Put the PEEK block on the nozzle and the two M3 rods. The smaller 8mm end of the central hole should be uppermost and should bear against the flange on the brass nozzle. The larger 10 mm hole in the PEEK is to reduce thermal conductivity between the brass and the PEEK, to keep everything cool."
