Note: The Batch 2 (and later) hot-ends are different than Batch 1. If your stepper plastruder is not a batch 1, please use the instructions for your batch. If you are assembling a MakerGear Prusa Mendel you do not have a batch 1 hot end - use the batch 2 and later instructions.

[If you are assembling the Mendel Mount, please read the mount instructions before assembling your hot end as you'll have one additional step.]

The V3 Hybrid and one-piece nozzles are designed to fit easily but precisely together. Unfortunately I made a small error in the one-piece nozzle specifications that results in a small gap. It does not appear to be a problem with ABS but PLA can leak out of the threads. We'll run-off new nozzles to replace the existing ones but that will take a few weeks. In the meantime you can use PTFE tape to get printing.

1/2" Teflon tape, the kind you get for $1.00 at the home improvement stores was used here. Three tight wraps should be fine. Wrap it clockwise so that it does not come undone as you screw it in. The barrel needs to go in precisely 12mm so you my may want to mark that position on your nozzle. With three wraps, you should be able to screw in the barrel (using pinch nuts as shown) by hand. Be sure to get the nozzle threads lined up with the V3 Hybrid threads. There are a number of other high-temp thread sealants available but I have not tried them and this is just an interim step until the new nozzles are ready. After your nozzle is in, measure from the tip of the nozzle to the bottom of the V3 - it can not be more than 20mm. If it is more than 20mm then your nozzle is not all the way in.

The parts to resolve this issue are now available - contact us.

Once the nozzle is all the way in check inside to make sure no Teflon tape protrudes into the inside of the barrel. And run a small hex wrench or screw driver along the inside edges of the barrel and V3 hybrid - it the should be a seamless junction. If there is a gap the nozzle is not all the way in. Remove any excess Teflon tape (or other thread sealant) from the exposed portion of the nozzle.

Step 1: Connect the barrel to the insulator. Threaded the turned down end (the end with the threads removed) into the V3 Hybrid GrooveMount (the PEEK piece). It should go in very easily. If it is at all difficult to thread it, remove the brass barrel and try again. Screw it in until you meet resistance then give a little twist to tighten it (you should not need to turn it more than an 1/8 of a turn after you meet resistance to get it tight.) You don't need to use any tools, hand tightened is fine. If you want to be sure it is in all the way, you can mark 12mm from the turned-down end as it goes in precisely 12mm. The barrel/nozzle is 32mm long. The V3 Hybrid GrooveMount is 27mm long.

Step 2: Attach the HeatCore. Thread the HeatCore onto the barrel with the wires pointed away from the nozzle (as shown). Screw it on until it is about 0.5mm from the PEEK. You are just avoiding direct contact between the HeatCore and Peek.

Step 3: Attach the Brass M6 nut. Screw the nut on until it makes contact with the brass portion of the HeatCore. If there is any ceramic on the bottom of your HeatCore either scrape or sandpaper it off. The nut should make flush contact with the HeatCore. Gripping the Heatcore firmly with your fingers, hand tighten the nut against it. This will lock the nut and HeatCore in position. You can use pliers to tighten the nut against the HeatCore but just turn it a bit - a lot of force is not needed. (but don't really tighten it until you at least read Step 4)

Step 4: Attaching the Thermistor. Taping the thermistor onto a face of the brass nut is the toughest part of the assembly. If you have a drill handy you can remove the nut (that you added in Step 3) and drill a small divot into the surface to make it easier to attach the thermistor but this is not necessary. Cut off a piece of polyimide/Kapton tape a few inches long and attach the glass bead to the nut. Kapton is not super sticky so you may want to do the first wrap not loose but not really tight. Then do several more tight wraps. The Kapton is probably going to extend out over the nozzle when you are done so use diagonal wire cutters or sharp scissors to to remove the excess. If the thermistor is not securely attached when you have finished the taping it, remove the Kapton tape and repeat this step until it is securely attached. (We also have high-temp thermally conductive epoxy available if you'd prefer to attach the thermistor another way.)

It is very important that your thermistor is securely attached. If it comes loose your hot-end will run hotter to try and compensate. This will likely result in leaks and/or jams.

Step 5: Attach the rubber-coated Fiberglass Insulation. Slide the insulation over the nozzle and HeatCore. The insulation should sit just above the nozzle and and below the PEEK (or it may slightly overlap the PEEK). Just keep it slightly above the nozzle so that it does not interfere with your prints.

Step 6: Mount the Hot-end as appropriate for your setup.

Note: Though we've included a HeatCore in the Stepper Plastruder Kit, you can substitute a Power Resistor based heater if you prefer. Power Resistor Kits are available in the HeatCore section of MakerGear.com