It can happen that the wing of the screw touches the BEEP base, so you are not able to tighten it completely.
We have three options to solve this problem:
1. Get a new Allen bolt at the hardware store, it should be a stainless steel M6 and 18mm long.
2. We can send you an new wing nut.
3. You can saw the wings of the screw to make it fit (not our preferred option).
Please get in touch with us if we can help you with this issue.