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I continue to flounder with extruders. I started with QU-BD and have moved to Bart's modifications, Makergear, and J-Head. J-Head seems to be the rave. I can't get it to extrude though. Without the hot end, you can barely hold the filiment from moving with two fingers. But, I have difficulty getting any of the filiment to go through the extruder even when assisting with fingers. I bought two of the J-Heads for 1.75mm.

Upon disassembly of the extruder I found that I actually had some melted plastic sticking back out the top! I got the head hot and pulled a piece of plastic out of the extruder that is 3.2mm in dia. I checked the unused extruder and the tube going down into it is over 3mm in dia.

Does this mean they sent me the wrong hot ends?

Most likely. Is your J-Head from hotends.com, or some other source? (I'm asking because there are some horrible 1.75mm modifications on eBay, which don't really work.)

You definitely have 3mm hot-ends. They'll run for about a minute with 1.75mm filament, but the plastic starts to fill back up the thermal barrier and then it will jam, as you've experienced. The retailer should fix that, otherwise you can buy or make replacement parts. I would have the retailer take care of it, though.

Thanks for verifying my problem. I have been pulling my hair out.

They are the "real deal" bought from JDS Labs

Never heard of JDS - the "real deal" is Brian at hotends.com - but I think everyone else is right and you've been shipped 3mm versions.

There was a "conversion" kit for the Chinese clones that basically stuck another piece of PTFE tubing with a 2mm inside bore - I've a friend who ordered one from eBay claiming to be for 1.75mm and that's what he ended up with...

tmccafferty wrote:Thanks for verifying my problem. I have been pulling my hair out.

They are the "real deal" bought from JDS Labs

Hmm.... Have I been tricked? I looked back through my email/order and I ordered from RepRap-USA.com and it says "J Head MKV-B Hot-End" but the shipping notice comes from JDS Labs. I understood they were a distributor for hotends.com. Is that not the case?

Ah.... I did find email correspondence I had with JDS Labs that indicates they are a distributor for Brian.

Sounds good to me - and should hopefully be straightforward to get them to send you the 1.75mm version.

tmccafferty wrote:Ah.... I did find email correspondence I had with JDS Labs that indicates they are a distributor for Brian.

That's interesting. I thought JDS Labs only did audio stuff.

Looks like everybody is out of stock. Argh!

Is the only difference the liner tube? If so, I could maybe buy tubes.