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Posted to uk.d-i-y
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Kitchen unit fitting sequence - base then wall cupboards?
wrote:
On Saturday, 24 August 2019 10:03:04 UTC+1, Chris Green wrote:
tabbypurr wrote:
On Friday, 23 August 2019 20:33:05 UTC+1, Chris Green wrote:
A well fixed steel screw will hold an incredible weight in shear. My
rule of thumb for steel's strength is 40 tons/sq in which gives a
shear strength of somewhere around a ton for a 5mm screw. The screw
will probably fall out first of course but I do always wonder why
people use great fat fixings for holding a few tens of kilograms.
Nearly all my fixings are 3.5mm or 4mm screws in yellow plugs and I
can assure you they *don't* fall out or break.
Many do. Some suffer from masonry crumbling, or the masonry simply snaps.
Most people fail to clear the dust out, resulting in a weak bond. And the
ida that you can reliably safely support a ton on a bit of 5mm wire sideways
strikes me as decidedly optimistic.
I wasn't suggesting supporting a ton on one screw, I was just pointing
out that big screws are unnecessary. It is of course necessary to
ensure that the screw is soundly fixed in the wall which, I find,
doesn't depend much on the size of the screw. *Longer* screws often
help but *fatter* screws are not a lot of help.
You were. I was pointing out that was not correct. Maybe you're upto speed now.
I said:-
A well fixed steel screw will hold an incredible weight in shear. My
rule of thumb for steel's strength is 40 tons/sq in which gives a
shear strength of somewhere around a ton for a 5mm screw. The screw
That doesn't mean one *should* support so much on a single screw, it
was just pointing out that it's not the screw that is the limiting
factor when fixing things to the wall.
--
Chris Green
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