I didn't like available models, so I designed one on my own. I had 4 main goals in mind while designing it:
I think that this model checks all of those boxes.
Ptfe connects collinear with the other tube. in middle there is 3d printed groove that has y-split for manual feeding.
Hardware:
4*M4x20mm bolts
4x M4 heated inserts (or nuts)
I used these:
https://cnckitchen.store/products/gewindeeinsatz-threaded-insert-m4-standard-50-stk-pcs
Print is designed to work with 4mm heated inserts and bolts, but also works really well with nuts and bolts.
Printing:
I recommend printing in orientation that is in the 3d file.
I used default settings on bambulab x1 carbon.
Please test that filament feeds effortlessly trough the block before assembling to see if there is need to modify slicer settings.
There is difficult bridging that may be needed to remove with something sharp to enhance it's reliability.
Installation:
Additionally you can deburr inside of PTFE tube that it feeds to.
Here is gif on how it works:
Gif on how well it clamps ptfe tubing
The author marked this model as their own original creation.