Hey Fred. Indeed these Cubes can be frustrating having gone through all the iterations to get to where we ended up. There is no consensus among users. But the fittings issue lingered regardless.

I've settled on a version of a 'universal cart'. It is based on the early work you are familiar with. However, it settle for using the stock cartridge case with the only purchased item being a 'qualified' bowden tube. And a niche requirement that a bowden tube be 'grooved' to provide an alternate means to hold it in place.

For the printed parts, life is simple; hot end is 3 parts; cartridge is one part; and the bowden tube is 2 parts.
The Cartridge case can be mod'd or left alone. I recommend a generous cutout in the cover for external spooling.

Two means of make a 'grooving tool' are also covered. However, this is where I loose interest from most. I have a simple way to do it on a lathe but it is certainly not the only way.

The system requires some maintenance in cleaning the nozzle from time to time.

I would love to have the time and space to do an 'instructable' on this just to explain the various elements if nothing else. It really is a simple process with real advantages.

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...now back to the subject at hand. I am sure other printers could be adapted to use a similar technique. Basically this is a captive tube secured by a tube-nut.

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