Tube Wrench for Stuck Astrophotography Extensions, Spacers, & Adapters

Works alright. Made for the SVX102T flattener and reducer, but can be easily resized to your needs. I used one successfully on threads, and a pair on smooth tubing. 5mm thickness is fairly sturdy and makes alright contact. It can still slip, and it can be a struggle to separate a thin, really stuck piece. A thin strip of duct tape on the interior circumference adds a lot of friction and really helps. Ergonomics are terrible, but it sure was easy to model & print.

Modify it for your imaging train:

Use the Measure tool in PrusaSlicer to rescale the model to fit your situation. After you click the measure tool on the inside diameter circle (shown in my attached screenshots), click the pencil icon to edit the dimensions. You're entering the radius, so make sure you use only half the diameter for the value. After that, you can turn off Scale Locking (see screenshot) and alter just the Z-height to get the right thickness (5mm is a good place to start).

Consider oversizing the ring just slightly, especially if you're going to add some high-friction tape around the interior circumference.

Print settings used:

The pictured prints are made from Jessie PETG, 25% gyroid infill. I used brims, but PETG is always a jerk for me about lifting up during a print and ruining geometry.

It's best to print a pair of wrenches for maximum torque.