Gaggia locking plastics for group collar / retaining ring

Many old Gaggia machines used these plastic parts to reduce the wear caused by the Stainless Steel retaining ring and the brass portafilter. 

It was a bad design decision, and since retaining rings are hard to come by, this is a great option to give your espresso machines many more years of use. 

Print in ABS or ASA. This part will be in contact with heated metal!

I printed with 4 walls and a concentric top surface to have print lines that follow the path the curvature, but other settings should work.

This part fits several machines:

Gaggia Classic V2 2015 (RI9403, SIN035U)

Gaggia New Espresso Dose (RI8153)

Gaggia New Espresso Color / Pure (RI8154, RI9302)

Saeco Nina (SIN026XH)

Saeco Nina Cappuccino  (SIN026X)

Saeco Sirena/Starbucks Sirena (SIN025RX)

Rounded teeth and fixed some surfaces