This is a very specific use case, but I had a Dahua camera designed for a Dahua PFA136 adapter that I needed to fit to a Dahua PFA134 junction box as we didn't want to buy and install a new junction box.

The Dahua PFA136 has a larger diameter - this is the part the camera screws into. There are appropriately spaced and positioned M4 heat set insets - I used M4x5x6 heat set insets. This will match the screws that came with your camera, or alternatively you can buy some M4x8 screws and they will work too. You'll likely need to buy at least 3 of these screws as only 3 come with the camera and you'll need 6 in total to do the adapting.

Then there are 3 similarly appropriately spaced and positioned holes which go all the way from the larger diameter to the smaller diameter side for the same type of M4 screws to screw into the junction box.

No guarantees on waterproofness, I'll keep an eye on it. I also printed in PLA, but I imagine PETG would be better given I'm using it in an outdoor environment.

Print with the smaller diameter side on the bed and you won't need supports.

I've attached the Fusion360 file as well, where I've included the following user parameters so you can customise for different types of cameras and junction boxes:

• NewDiameter: The diameter of the side you're attaching the camera to (ie should match the camera's diameter)
• OldDiameter: The diameter of the side you're attaching to the junction box (ie should match the junction box's diameter)
• NewHoleDiameter: From the center, the diameter of the circle where the screw holes for the camera to screw in should be. Basically how far away from the center the holes should be.
• OldHoleDiameter: Same as above but for the holes so you can screw into the junction box.
• ConnectingHoleDiameter: The diameter of the above hole ^. You want this to be as wide as the widest part of the screw you're putting in (ie the screw head)
• HeatSetInsetDiameter: The diameter of the “NewHole”
• Tolerance: Adds an offset to some dimensions to make fitting parts together easier when 3D printing
• HeatSetInsetDepth: How deep the hole is for the heat set inset (ie the “NewHole”)
• ConnectingHoleInnerDiameter: At the end of the connecting hole, the size of the hole for just the screw shaft (ie the hole becomes small at the end so the screw actually holds the adapter and doesn't just go through the connecting hole). This should be the diameter of your screw shaft.

Let me know if any questions and would be keen to see if anyone actually makes this!