How to fasten Y axis approximate sensor rod?

Last night while working on our newly built Shapeoko4, machine initialization could not stop when moving away the gantry along Y axis. Turned out the cylinder-shape rod to trigger Y axis approximate sensor fell out of its place, causing the Y axis approximate sensor not detecting the gantry had moved to the end of Y axis.

We manually screwed the rod back, but not sure how to fasten it. Would be great to have a hole at the top so that I can insert an allen key to fasten.

It should be secured using threadlock — please let us know about this at