Body Tube diameter== Out =75mm || in 72.5mm

18mm = a b c rocket engine => 18mm uzun kulak.stl 24mm = d rocket engine n. => 24mm 3.stl

when first assembled the resistance between screws are high ( need to oil it up and manually move the nozzle x and y axis around 10 minutes).

if possible Machine Screws 2 x (M2 screws ±20mm length) 2 x (M2 screws ±15mm lenght)

1 x(±1mm metal-rod 36) 1 x(±1mm metal-rod 20)

servo = SG90 or anything with the same dimension MG90s

Can use screws or pvc glue to combine parts.

The design will be improved