Help identify this door/window part?

[A930Rocket]

I bought the coupling and carriage bolt, but after looking at the pictures online, the square part of my carriage bolt is too thick. I need to find one that matches the bolt online so it doesn’t bottom out. Also, I will need to cut the coupling down.

Back to Lowe’s…

[WMichelsen]

Interesting how thick that square carriage retainer area is.
Another option is to add a washer. There is enough room between the spring and regulator.
Might have to file the corners down where it protrudes too tall.

I thought about a washer just to increase the contact area at that point.
When I cut and shortened my coupler (barrel nut), I installed it so the flat cut-off side was toward the regulator, for that reason. (The coupler itself is rounded a bit.)

[Fab64]

I filed a carriage bolt down so it would fit in the slot on the regulator. Started to file the square part down, then realized a regular screw would work. Here's what I ended up using:





I still had to file some off the head (flattened it out a bit) to provide clearance between the pieces. I applied some red Loctite before assembling.