Need help with twin slot shelving!

[savvysquirrel]

Hi,

So I've bought this twin slot shelving system to go up in one of our hallway cupboards.
www.diy.com/departments/form-twinny-white-shelf-rail-l-200cm/3663602767107_BQ.prd

I'm new to DIY and drilling so I was wondering if someone could give me some pointers. I read on another thread to get 5mm x 70mm screws for it and use brown wall plugs.

The wall plugs however are only 30mm long and require a 7/8mm hole, I will probably do 8mm hole as I don't have a 7mm drill bit. But my question is if the screw is longer than wall plug and the screw is only 5mm do I drill a pilot hole with a 5mm drill bit that is the depth of the screw and then drill an 8mm hole that is the depth of the wall plug? As if I drill an 8mm hole the depth of the screw won't the screw be loose?

Sorry if this is a really stupid question but the other things I've drilled the wall plug has always been the same size as the screw. Any tips or advice would be great. Also please let me know if I should be using a different size screw.

If your using a brown wall plug, drill a 7 mm hole 8 will be too big. The hole needs to be deep enough so the screw doesn’t hit the .bottom of the hole ( same with any length of screw) . So if the wall brackets are say 20 mm thick then the hole will need to be at least 50mm deep =70mm but I’d go a bit deeper to be safe.

I always drill the hole , put the wall plug in and tap it flush in the wall, then put the screw in and tighten it with your fingers, then tap it in with the hammer so it’s into the solid part of the wall( you don’t have to knock in all the way to the bottom of the hole.
If the plug is halfway down the hole the long screw will just go through the plug.

But 8 mm drill bit will be too big and the plug might not tighten properly

Depends on how solid the wall is and how much weight will be on the shelves, you could use a thinner gauge screw and use red plugs 5.5 bit and it would be fine.

Thank you @Chumleymouse this makes complete sense. Ok so I will get myself a 7mm drill bit and then measure the bracket to see how far I need to drill.

Luckily as it's going up in the cupboard it doesn't matter too much if I mess it up. Then once I'm confident with drilling I will attempt to hang my mirror as well. Wish me luck!

You can measure how deep you need to drill on the drill bit and wrap a piece of tape around it , then when your drilling it’s easy to see how deep you need to go . Also if you don’t want to make too much mess when drilling , hold ( or get someone else) the hoover just under the hole and it will catch most of the dust . Good luck 👍

how old is the house, and what are the walls made of?

throw away those silly little plugs.

The plaster might be 15-25mm deep depending on age or construction. plaster has no strength. You need to go about 30mm into the brick or block behind the plaster.

On slot shelving systems, the screw at the very top is the most important, because leverage of the shelf will try to pull it out. have the top of the columns well above the top shelf.

ps

when you buy a block of brown plasplugs, look at the plastic rectangle in the middle. On it are embossed the recommended sizes of screws and drills, and example holes for you to check.

Look