Screwing a screw into a fixing/plug (wrong size?)

[James Hanley]

I bought some equipment it came with screws. It needs screwing into the wall. So I bought some plugs/fixings from homebase. The end of the screw doesn't seem to reach the end of the plug/fixing, and it splits at the bottom. Here is a picture

fixing box says says No 5,8,10,12 3.5mm to 5.5mm wood screw

IT says that the screw must penetrate 25mm into the fixing. Fine, the screw is 25mm long. But the picture on the fixing box shows it reaching tho the end of the fixing - the fixing is 30mm long and also, the picture on the box shows it fitting snugly without splitting the fixing.

Is this the right size fixing for the screw? And do I just drill a hole and if the hole's too small find a slightly bigger drill bit. The box says it needs a 6mm masonry drill. But i've done it before using drill bits and getting bigger until it fits. I don't know what size my drill bits are but I know that at least one is an ok size.

[Colin Wilson]

What sort of surface are you trying to fix it to ?

(I spot no brick / plaster dust, so i`m curious)

[Andrew Barnes]

Are you sure that plug has been in a wall? If it was inside a drilled hole, it wouldn't split like that i dont think.

[a]

got ones big enough! The plug should be a snug fit in the hole - I like them quite tight and tapping them home lightly with a hammer is better than them being loose.

That picture looks like the screw has gone in at an angle?

[Andy Pandy]

Kidding!

1 The plug may be sub standard and brittle ! 2 In my experience any screws that I get already included with equipment that i buy are strange sizes and weak so i use some that i have pre bought in a pack at a earlier time.

Try a slightly thinner screw ! I think it would still do the job and yet give the plug less strain !.

Good Luck

Andy

[Peter Andrews]

They are not suitable if it's a plasterboard wall. If it is brick then drill a 6mm hole at least as deep as the plug is long, insert plug until it's flush with the wall and then insert the screw. This should be OK for a No. 6 or 8 screw, however if you are using a No.10 screw you may need to make the hole 6.5mm diameter. I don't think that whatever you are fixing can be heavy as the manufacturer would have supplied longer screws than

25mm.

Peter

[a]

perhaps it is a plasterboard wall?

[James Hanley]

either the picture on the box of plugs is wrong. Or the plug and screw aren't matching - perhaps a bad plug. Which is it?

It might be that the wall is plaster, and behind that, brick.

If I can screw in easily, it would have to be plaster, right?

If it is plaster, what plugs do I get? Do I get plugs?

What I am fixing will be carrying up to 15 stone = 210lb = 94kg

It's a chin up bar. I'll start off with just my bodyweight, then do them with a really heavy rucksuck on.

[Colin Wilson]

In that case, you need a solid fixing into brick, or at very least, the framing of a stud wall. I`m slightly paranoid about fixings, but I would be looking to use a rawlbolt or two personally, and they must go into a solid wall.

[Christian McArdle]

Agreed. The idea of using a couple of 25mm screws to hold a person's weight frightens me. I would also be on rawlbolts here, or pre pilot drilled 6mm x

75mm screws into studwork, making sure they're tight, so that the main load downwards load is taken between the wall and the attached item, rather than relying on the screw's shear strength.

Christian.

[Andy Dingley]

Chin up bars _between_ walls are easy enough though. Because they bridge two walls, they're a pure shear load on the fixing, with no tendency to pull out.

Not that I wouldn't be using some honking-great plug or Rawlbolt myself.

[Christian McArdle]

But it is surely better to relieve the fixing of any shear load by clamping the attached device to the wall to provide friction between them? Then the fixing is there purely to provide clamping force and not resist any downwards force itself.

Christian.

[James Hanley]

what if the wall isn't brick, but is plaster?

[Dave Liquorice]

The wall will fall down under it's own weight. Plaster is just a finish any load bearing, including its weight, is carried by something else. Either the wall it is stuck to or the framing plasterboard is fixed to.

[Andy Dingley]

Then you should use whatever is easiest to put up. That way you'll break a lump out of the wall sooner, realise that such a wall can't take the load whatever you use, and get on with fixing it more quickly.

If you live in a recently built house (or anywhere in the USA) then it's largely impractical to fasten either pull-up bars, punchbags or climbing walls.

In my place (late 19th) I can hang any weight I like off any wall. But all fixings need to be three inches long (even for towel rails) because my strong walls are hidden beneath a century of replastering.

[James Hanley]

the bar is meant to fit between a doorpost(but my doorposts aren't high enough, so i'm fitting it between 2 walls), does that mean that I have wood screws and shouldn't be screwing them into a wall?

[Christian McArdle]

You really need to find out what your wall is made from before you go any further.

Christian.

[James Hanley]

ok, so would you and adam agree that if I got a wacking great Number 8

3" screw with a wacking great 3" fixing, then it'd go through the plaster into the brick and do the job?

I think it has to be number 8(i'm assuming that's diamater), because it came with things that screw into the wall like this

------- ----- | | | | | | |------ -----

So the bar expands into those things. And those things have holes in them where I screw them into the wall.

I guess I could make the holes bigger and use a thicker screw. But would a number 8 3" screw go through the plaster into the brick and do the job?

And what size fixing would I use for a 3" screw? The make i'd use would be the one people keep mentioning in this thread

[Christian McArdle]

I only work in metric. For this I would use a minimum of 6mm x 70mm, assuming normal plaster depth, or rawlbolts. Ensure that you get well into the brickwork. If it pushes in too easily, you've hit mortar and should start again somewhere else. Ensure that the screw/bolt is tight. Remember that its purpose is to pull the bracket onto the wall and it is the wall/bracket interface that resists downwards movement, not just the screw/bolt.

Christian.

[Rob Morley]

Probably easier to fix a bit of timber to each wall - you can use four (or more) screws to fix it, so it doesn't matter if the odd one isn't very secure. Then fix the bar to the timber with the supplied fittings.