Review: J-Head Nozzle

The item

The item I will look at here, is the J-Head nozzle Mk III-B by Reifsnyderb.

At first look, it looks fine, a bit rough on some of the surfaces, but not something that should affect the printed parts.

To mount it, you take a plate with a grove in, put the hotend through the X carraige, and then slide the grove in the plate over the body of the hotend, followed by bolting it down with the extruder on top. This was easy done, and only took a few minutes.

A thing I really like about this hotend, is that you can start by mounting it to the printer, then easily add the temperature sensor, and also the power resistor. This means it is also very easy to replace any of those, without having to take the entire extruder apart before being able to take any of them out.

Another interesting thing is the aluminium piece added for cooling. It is basically a bar with a hole in the middle, that the internal PTFE tube will slide through, and the aluminium will then stick out on each side of the PEEK body of the hotend.

To be able to compare it with the other hotends I have tried (Arcol and MakerGear), I am printing without any additional fan or any extra cooling.

After putting it on the printer, I tightened everything up as I normally do, but my prints were strange, and it looked like the filament inside the nozzle was not getting through the nozzle with a steady speed, even when the extruder was steadily pushing it in.

Printed a few items, but they were all useless, then loosened the extruder enough so it would no longer grip the filament, and pushed the filament in by hand. I then noticed it took quite more force to push the filament through than the other nozzles I tried. Tried higher and lower temperatures, without any change. Next step was then to try and just tighten the bolts on the extruder some more, and hope that would be enough.

After loading a gcode for a thing I knew had printed perfect with my other nozzles, I gave it a go again. Success! Almost… The thing that came out could be used, but could still do with some tweaking.

A few weeks passed, with a bit of tweaking, and my prints are now as I like them, or the things I want to correct next, is nothing the hotend can help me with.

During the time I have been printing with it, I have used 3mm ABS plastic, and the 0.5mm nozzle. While cooling down from 210c, it only oozes around 15mm out, and could even be left heated up for 10-15 minutes without having all of the plastic dripping out of it.


These pictures were taking after around 30 hours of printing


Is this a reliable hotend?

I would say yes, during the time I have used it, I had no problems at all with it, after I got the screws tightened more to press the filament harder against the hobbed bolt.

How long does it take to heat up?

I have been running it on 13.4 volts, and with that voltage I heat up with between 4 and 7 degrees Celsius pr. second.

How hard is it to assemble?

Assembly is extremely easy, all you need to do is actually to put the power resistor in, and add a temperature sensor, both can easily be secured with kapton tape. Assembly time is less than 10 minutes if you have tried something like this before. For a beginner I would say less than 30 minutes from you open the bag, until it is ready to print.

Would you recommend this as as beginner nozzle?

Absolutely, it is easy to put together and can easily take some collisions without breaking.


  • Easy to assemble
  • Reliable in use
  • Heats up fast
  • Cheap and easy to get spare parts


  • A bit rough surfaces.
  • Non chamfered edges on the groves on the aluminium cooling bar.
  • A bit harder to push filament through.

Some printed parts


The printer

The printer I tested this on, is a RepRap Prusa, upgraded with LM10UU linear bearings on all axis, and also with 10mm smooth rods.

Another upgrade is the X carriage, which is made out of a single aluminium piece.

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