Hot end dimentions

I want to make an extension for my hot end but do not know what size of drill bit to get for 1.75mm filament. I was reading THIS page and the PTFE liner they use is 3/32 and it looks like the J-Head's use a liner with 1/8" ID.

What is the best size to drill through my 6mm rod so I do not need a liner??

2mm for 1.75mm and 1/8th for 3mm

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1/8th being 1/8th of an inch, or 3.175mm.

yep

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Stainless steel seems to be the choice nozzle material for all metal hot ends but it is a pain to machine. I can do brass, aluminum and steel. Which one would be the best second choice?

Also because stainless has such a low heat conduction you can get away without a PTFE liner, if I change to another metal do you think I should even bother making one without a liner or am I asking for trouble?

Edited 1 time(s). Last edit at 10/22/2013 07:06AM by uMinded.