So close it’s killing me! Good smooth extrusion is eluding me. If I push the filament, I can get some plastic out, and migrating to the real pneumatic fittings and PTFE made things better, but I just can’t seem to get it to spit out plastic reliably. (.35 1.75 hot end)
When the hotend is hot, gentle hand pressure on the filament (with the extruder idler open) should let you push plastic out easily. If that’s not the case I’d start by taking the filament path apart and looking for a place where friction is too high. You might also have oversize filament, check the max diameter with your calipers…
You could perhaps go direct drive with the j-head and 1.75mm filament. You will then have more suitable drive gears to choose from. The teeth look too chunky on the bolt your using.
It takes a LOT more than gentle pressure to feed the filament. I’ll take a look at it tomorrow, but that’s a helpful piece of info. I wonder if temperature has anything to do with Altitude? It affects cooking, I wouldn’t be surprised if being 1 mile above sealevel wouldn’t affect filament melting .
If it’s PLA you’re trying to extrude, you will need some cooling on the hot end PEEK barrel. I can’t see a fan on your set up.
That’s because it’s sitting on the table next to the printer. 
Sounds like the next step!
I’ve also found the filament is a whole lot closer to 1.80mm than 1.75mm, would that be enough to throw things off?
1.8 should be fine and Ive taken my machine from mile high to sea level in 12hrs and it prints the same either way. Sounds like the hotend is not as hot as it thinks or theres something wrong with the filament path.
It seems that the nozzle is too low. I see there are scratches on the tape made by the nozzle. You should check that a sheet of paper can move under the nozzle when Z=0. The paper shouldn’t move freely but with some drag from the nozzle.
Sounds like a clogged nozzle. Dragging the head on the bed is like putting a cork in it.
Speaking of filament size, didn’t I read that moisture, as in humidity, could be an issue?
Question from a newbie here, not an answer…
I agree with @Brook_Drumm , your nozzle needs clearing. Try running the hot end to temperature, and pushing the filament through. Then pull the filament back out quickly, cut the end to get a clean to, and repeat. This is how I clean my Makerbot replicator nozzles, that clog like they’re getting royalties. After 4 or 5 repeats, the filament should flow better. If not, keep trying. Another extreme option is to take the nozzle off and use a blowtorch to burn the plastic out, then use some fine bus wire to poke debris from the outside inward.
Moisture is unlikely…winter in Colorado is a pretty dry place. Where do I acquire a .4 mm (or less) pipe cleaner? :) the head has been drug through the tape… I haven gotten the dimensions fully calibrated yet. (There’s several things competing for my debugging time.)
Just find some solid core wire. I use wire wrap wrote at work, but you can probably find some solid core cat 5 cable and get a strand out, might be small enough, 28 awg? May need a confirmation on that. Try the filament trick first. Do you have a dust cleaner on your filament? I put a binder clip with a paper towel was clipped in it around my filament. Cleans lots of dust of and makes cleaning the nozzle less painful and less often
what mechanism is feeding the filament to the hotend?
It’s the standard 3DR Bowden setup, one of the debug issues is working out the tensioner as I had real problems getting one of the trapped nuts into the base without it delaminating. I get the impression a properly running system wouldn’t need a lot of pressure to drive the filament, especially with the aggressiveness of the drive bolt.
@Mike_Miller , you’d be shocked by how tight your tensioner needs to be. Try replacing with a spring tensioned design like the minimalist extruder. But regardless of your extruder and Bowden tube, filament going through a hot extruder by hand should only require pushing the filament with pretty minimal force.
Thanks, I’ve got zipties cranked down and holding it while two M3-35mm bolts are being sent to me…it’s the fringe parts in the build that are killing me.