How much weight can be hung from a 5mm stainless steel screw (50mm long), in a brown raw plug, in a brick wall (7mm hole drilled)?

[dragonfly101]

Surprisingly difficult to find a straight answer from google on this. I need to work out how much weight I can put into this new bathroom cabinet I've just hung.

 

[blup]

Use at least 75mm screws because you will be drilling through plaster before you hit brick. Hanging brackets should support the cabinet and anything domestic that fills it. You can get hanging rails if you want belt and braces.

Apart from that, your question is how long is a piece of string.

Blup

 

[dragonfly101]

It is actually 80mm, I gave the number 50mm because that is the length of the raw plug. The IKEA cabinet I'm hanging is annoying in that it has long gap between where the screw head stops, and the wall (hence I'm having to use a longer screw).

Is there any point in using 75mm screw when you can't seem to get raw plugs that long?

 

[Johntheo5]

You can get rawl plugs in lengths that you cut to the required size, these are much more solid than the pre cut ones that I never use.
Google 5x300mm rawlplugs that you can buy in different diameters.

 

[JohnD]

You can also tap the plugs in deeper. I always tap them below the surface of the plaster to avoid cracking, but since plaster has no strength, you can tap them deeper. Touch the screw to the hole in the plug and press or tap it lightly. This avoids not being able to find the hole when it is out of sight.

 

[dragonfly101]

"You can get rawl plugs in lengths that you cut to the required size, these are much more solid than the pre cut ones that I never use."

Thanks, now I come to think about it, I do recall having seen those. Strange that DIY shops seem to hide them, and just want to sell you the short moulded ones (or even the packs of screws and plugs together). Even a search for 'wall plugs' on screwfix only turns up fixed size ones, nearly all less than 50mm.

There are no holes I ever drill in walls in my house that won't be covered by whatever is being fixed there, so perhaps I can just simplify my toolbox by having just one masonary drill bit (7mm), a length of brown rawl plugs as mentioned, and some 75mmx6mm screws - I'd imagine these would be good for nearly everything you might want to put on the wall.

 

[johnny2007]

A couple of years ago I tested the duo power plugs.
The 8mm with a 10x3" screw was holding my full body weight 200 pounds (used a racheting rope).
Tried the standard fischer 8mm and same.
I think that with down force they can hold a massive weight.
Problem is a leverage that tempts to pull them out.

 

[Tigercubrider]

And leverage can be reduced by longer screws.

 

[mattylad]

You can also push 2 rawlplugs in the same hole.

Then you can use different lengths of string to hang your weight on

Not knowing anything about the particular screw, its material, width, tensile strength etc. we cannot say, however a longer screw is going to do far better especially if it's good and tight in the hole.

 

[big-all]

a bathroom cabinet will tend to be fairly shallow and relatively lightly loaded compared with a say 350mm deep kitchen cabinet full off tins that by default will be between 2to 4 off 4.5/5mm 50mm screws
as said a screw in shear will take 10-20 times the load off a cabinet say half the depth to height ratio where a bit off leverage comes in
i would suggest unless your walls are crumbly each screw will easilly carry a 20kg load providing they are fixed to the top 25% off the cabinet as most weight is hung [in shear] rather than pull away from the wall [leverage]