Currently looking at masonry screws on the SF site.

I use Multi Montes which are great, but require a pilot hole. Are there
any on the market that can be driven straight in? SF site isn't clear on
this point.

The description says 'cuts thread into concrete, brick and hollow block' but
doesn't mention a pilot hole.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

The Medway Handyman wrote:
Currently looking at masonry screws on the SF site.

I use Multi Montes which are great, but require a pilot hole. Are there
any on the market that can be driven straight in? SF site isn't clear on
this point.

The description says 'cuts thread into concrete, brick and hollow block' but
doesn't mention a pilot hole.



No. Brick/block/concrete is essentially un-compressable.

When you screw a wood-screw directly into wood without a pilot hole, the
point cuts it's way through the wood and then the body pushes the fibres
of the wood out of the way putting them in compression. This couldn't
happen in dense brick/block/concrete. You have to drill out material
equal to the displacement of the fixing.

If you think about a multi-monti, your pilot hole represents about 99%
of the displacement of the fixing - it's only the spiral that locks into
the wall of the hole and cutting this spiral causes a minimal amount of
dust which gets lost in the interstices of the fixing hole.

You can screw a woodscrew into a thermalite blocks because as you screw
in, the air gaps collapse as the material is pushed out of the way.
However, the pull-out force is minimal.