Jhead conversion from 3mm to 1.75

Anyone knows how to convert a Jhead, latest version from 3mm fillament to 1.75mm.

I read on the Wiki, but dont really understand it, and besides I am more looking for a place to get the parts, without having to replace the whole hotend.


Cheers,

Jonas

Unscrew the brass piece from the black plastic piece and replace the plastic tube inside for a smaller one.

The inner plastic tube is made up of PTFE or PEEK and can be purchased at most online reprap stores.

Try Makerfarm or hotends.com or ultimaker or anywhere.

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-Tom

The inner tube is made of PTFE. You need a piece of PTFE tube that is 0.25 inch (6.35 mm) outer diameter, and approximately 0.08 inch (2 mm) inside diameter.

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Like the others have said you just need to replace the PTFE liner with one that has a smaller ID. If you have trouble finding a tube with the above mentioned dimensions another option is to purchase .25 OD PFTE rod (McMaster 8546K11) Then just drill it out to the proper size. I use this method for my j-head style hot end. Also PFTE rod is cheap (2.33 USD per foot)

Just for arguments sake, couldnt he also use PEEK or even metal tubing? I was under the impression that some people do this for printing at high temps with PC as PTFE will melt at extreme temps.

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-Tom

Sniper4395

PEEK has a lower temp them PTFE, and is not as "slippery" as PTFE. PEEK is used as the main housing just for its strength compared to making a whole housing out of PTFE. This is why the PEEK NEEDS to be cooled if printing in ABS.

Metal can be used but it also is not as slippery as PTFE, and if you drilled the ID out yourself could have some small burrs or drill marks that will catch soft ABS or PLA.

You are right Metal is used for printing at higher temps, but a J-head is not a hot end designed for such high temps. Even if you swapped out the PTFE with a metal tube the high heat would transfer up into the PEEK and melt it.

doesnt the nozzle also need to be replaced? for one that is properly machined? or could someone simply insert a 2mm ID 3mm OD PTFE Tubing and a washer with about 0.25" OD 2mm ID after the set screw to keep the whole thing together?

>This is why the PEEK NEEDS to be cooled if printing in ABS.

The PEEK does not need active cooling when printing ABS.

There is no such thing as a single "ABS filament". What one outfit sells works at 215 degrees, what another outfit sells only works at 235C (same setup for both, printing same object, sliced the same way, same speeds, same / same / same). If you run into an ABS that needs a true > 230C, you will need active cooling on your J-Head. The PEEK is only rated to 235. Depending on the batch it'll soften / melt somewhere between 237 and 247C.