How do you secure UD-USB adapter to HAS-Supergun?

[SelfDeniedHoarderz]

I am running HAS-supergun setup, hooked up to my CPS3 board and UD-USB adapter connected to 15pin terminal port on HAS-Supergun.
The thing is that the UD-USB adapter is not tightly secured or attached to 15pin terminal port on HAS Supergun.
Can someone please advise how do you go about to tightly secure the UD-USB adapter to HAS-Supergun? I know that you will need small bolts for this but I don't know the specific size

 

[ShootTheCore]

I've personally never worried about fastening my UD-USB to my HAS-it fits pretty snug.

That said, I believe the right fastener is a #4-40 0.232 inch screw. Like this:

https://www.amazon.com/CableWholesales-Hex-Jack-Screw-Pieces/dp/B000I98YZG