They are a bad choice for soft bricks, or solar blocks, but
ok provided you use the correct size drill and make a hole
deeper than needed to collect the swarf as the screw cuts its
own thread.

If I was the OP I would use expanding bolts for the top fixings
because they will carry huge loads.

Andrew

On 10/02/2020 20:42, Brian Gaff (Sofa 2) wrote:
No matter what the head type, never had much luck with those, I have to say.

Brian