I recently changes the nozzle on my Monoprice Maker Ultimate 3D printer (first time). The brass block that the nozzle screws into is free to rotate around an is wobbly.

Brass block

Loose block video

I can't see any obvious nut/screw that's come loose though. It could well be that it's not important, but it was definitely tightly attached before it twisted when I removed the nozzle.

I've taken the assembly apart:

Silver bit

Silver bit removed:

Silver bit


The silver looking cylindrical nut (with the flat faces) between the brass block and the black metal plate is the heat break of the assembly. The brass block should be tightly fit to this heat break. You could turn the brass block to get a close fit again. The heat break itself can move in the upper part, black plate, the cold end by the set screw on the side. Some hotend assembly types allow that, this screw is then used to fixate the orientation of the brass block. This type of hotend is not very common, it is a MK10.

Without the brass block it looks like this:

MK10 cold end and heat break

Maybe this clears it up how the block is attached in between the heat break and the nozzle; it is positioned where you see the threads. The screw to position the brass heater block and the heat break is clearly visible.

Don't try to wobble the brass block any further as you will wear out the threads, there appears to be a lot of play already.

  • $\begingroup$ Cheers, I've added a photo of the disassembled block. You're saying that the looseness is definitely a bad thing though and I need to find out what's loose and tighten that? $\endgroup$ – BanksySan Feb 1 '19 at 17:34
  • $\begingroup$ It just clicked that the hole is where the filament passes and is heated. $\endgroup$ – BanksySan Feb 1 '19 at 17:34
  • $\begingroup$ @BanksySan I've updated the answer, it should be clear now. Just tighten the heat break to the brass block and position the heat break in the cold end plate. $\endgroup$ – 0scar Feb 1 '19 at 17:37
  • $\begingroup$ Monoprice or ultimaker Mk10? $\endgroup$ – Trish Mar 2 '20 at 10:07

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