On 30/08/2020 15:54, Andrew wrote:
I am fitting a pocket door and the frame is an aluminium box section.
The instructions assume that the stud wall will be a metal construction
and advises screwing through the metal upright into the aluminium frame
using a self-taping screw.

But my framing is timber so I will need something like a four inch
self-taping screw to fix in the same way. I could get away with
something a bit shorter if I counter-bored the timber first.

In which case you could probably get away with a normal twinthread wood
screw (the end profile is not that different from a self tapper).
Predrill the ali with a drill the same size as the core of the screw,
and you will probably need an impact driver the drive the screw,

The frame is already installed so any holes in the aluminium will have
to be drilled through the timber.

Any suggestions?

Another less aesthetic option would be to drill and countersink the
frame and screw from that direction into the timber.

--
Cheers,

John.

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