I think the aim of the offset extruder was to allow the use of a wider range of materials by allowing stiff rods to be accepted. Its a clever design but it does have a few disadvantages:
It's harder to build and requires an extra material: steel cable.
The cable winds up, so when the motor stops it sometimes slips backwards unwinding the cable but sometimes it doesn't. That implies the motor does not have a worm drive which surprises me. Unless I fit a shaft encoder to the motor I may or may not have a slight pause in the start of a new run. Alternatively I could keep a bit of current in the motor to hold it.
You can't run the drive backwards as that unwinds the cable. This doesn't seem to be a problem with HDPE because it seems to stop immediately without any dribble.
The speed of rotation varies over the course of one revolution. I put this down to the cable joints being slightly eccentric, or perhaps the fact that the cable was coiled for ten years before I used it.
So it may be better to stick to the previous design unless you have a requirement for extruding material supplied in rods.
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