How J-Head™ Core Tubes Are Made

Hotend - J-Head Farmer core tube

At J-Head™, I am committed to providing high-quality hotend components that offer reliable performance and accuracy. Our J-Head Core Tube is no exception - they are made on a CNC lathe out of stainless steel and polished to ensure a snug fit in both the finstack and the heater block parts of the J-Head™ Farmer.

In this post, we'll take a closer look at the manufacturing process for J-Head™ Core Tubes and how I ensure that each one meets the high standards put in place for the J-Head™ brand.

Hidden Features:

The J-Head™ Farmer Core Tube offers hidden functionalities that are not immediately apparent. Unlike other heat breaks on the market, it is treadless, which is one of its distinguishing design features. This feature (or lack thereof) adds a level of functionality to the J-Head™ Farmer that other hotends don't have - the ability to adjust the length of the heat break.

A setscrew in the lower groove on the core tube holds the heater block in a fixed position, providing a firm footing for the nozzle to seat and seal against the core tube.

However, the entire core tube/heater block assembly is free to move up and down within the finstack.

Eliminate The Paper Test

This means that you can eliminate the paper test by having your printer go to Z0, loosening the setscrew, and having the nozzle drop down to your print bed. Then tighten the setscrew in the finstack again to lock it in place, and your hotend will be exactly where the printer thinks Z0 is. No more paper test!

Watch how you can simply loosen the finstack setscrew and drop the nozzle straight down to the print bed!

Dual Extruders:

But that's not all - if you have a dual extruder printer, imagine how tough it is to get both hotend nozzles to be at the same height. With the J-Head™ Farmer, you can easily achieve this feat by simply loosening both nozzles and tightening them on the print bed.

3D Printer Maintenance:

The third and fourth major features of the J-Head™ Farmer core tube are related to printer maintenance. If you ever get a jam or a clog.

  • simply loosen the setscrew
  • drop the core tube/heater block assembly out
  • pop in a new swap kit to get back up and printing quickly

This is why I call it the J-Head™ Farmer - because it was designed with printer farms in mind.

CNC Lathe Manufacturing:

I start the manufacturing process by using a CNC lathe to machine the core tubes out of high-grade stainless steel. I chose this metal because it has a low thermal conductivity, which reduces heat transfer from your heater block to the cold side of the hotend. During this step, I ensure that each core tube is free from burs and has a 2mm inner diameter and a snug fit on the outer diameter, as required by our strict specifications.


After the core tubes have been cut, I carefully polish them on both the inside and the outside. This step is crucial to ensure that the surface of the core tube is smooth and free of any burrs or imperfections that could affect its performance.

I take great pride in my attention to detail and believe that this extra step in the manufacturing process is what sets J-Head™ Core Tubes apart from other products on the market.

A J-Head™ Core Tube After Polishing

Quality Control:

Throughout the manufacturing process, I perform rigorous quality control checks to ensure that each J-Head™ Core Tube meets my high standards. I check the inner diameter, outer diameter, and length of each core tube to ensure that it matches the specifications. I also test the fit of the core tube in both the finstack and the heater block parts of the J-Head™ Farmer to make sure that it fits snugly.


Once the J-Head Core Tubes have passed the quality control checks, I package them carefully to ensure that they arrive at your doorstep in perfect condition. I take great care to ensure that these products are well-made and should serve you and you're printer well in the coming years.

I take pride in the quality of these J-Head™ Core Tubes, and I am confident that their performance will satisfy you and your 3D printer. My attention to detail and commitment to quality is what sets J-Head™ apart from other hotend component manufacturers. I hope that this closer look at my manufacturing process has given you a better understanding of the care and attention that goes into each and every J-Head™ Core Tube. Don't forget to share this with your friends, call your mom and tell her about this totally cool thing you read about on the internet today!

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