Here we go, another “Y” splitter.

Well, I couldn’t find one that I was happy with. I didn’t want one with an unstable and ugly fitting, and the ones that just held the PTFE inside “Press-fit” were too tight or too “loosely loose” (and you can’t glue PTFE). Then I make my own.

All internal filament paths have a radius of 75mm. The transitions 4mm to 2.25mm are taper 30 degrees with smoothed edges.

I printed it out of ABS 0.12L, 20 % infill, 3W, with a brim and supported; it’s nothing fancy. ABS should be better than PLA, but PETG may be even better as it is more slippery. I ran ABS, PETg and PLA-CF and didn’t have an issue. I’m happy as it is. If needed, I’ll machine it out of Teflon on the CNC in two pieces… But that is not as fun. ;-)

The mounting screws are (2) SHCS M3 x 16mm, and the thumb screws are SHCS M5 x 12 with a Knob cap press-on. It can use two M5 x 12 on the fixed tube and can have a thumb screw M5 x 12 for the auxiliary intake. Here are the caps I used: https://www.mcmaster.com/91175A063-91175A630/

Thumb screws (Amazon has it, too) https://www.mcmaster.com/92552A442/

For the PTFE, I did test some 3.9 to 4.2 OD. with no issues. Notice the filament path is 2.25mm, and I did chamfer (60 degrees total) the inside of the PTFE to make sure the filament edge can’t get stuck in the transition.

I may make a new model that doesn’t need support and has nuts for the one that doesn’t have taps. This works, and why should I fix it?

Enjoy.