When screwfix state use a 16mm hole with their ..
and ye have a hefty ancient SDS* giving the bit lots of side wobble, use a 14mm.
Or, should I update my SDS drill for cleaner holes?
I find I get a much bigger hole in soft, friable bricks or blocks than I do in slate. But then I use a cheap SDS drill and worn bits too. I tend to try an undersized drill first with large frame fixings, I am interested to know what others do.
Earlier this week I was sticking matchsticks in the holes alongside the wallplugs and hoping for the best.
I suspect that not all 'red' wallplugs are the same size or expand equally.
Owain
I do the smaller drill bit thing too e.g. 5mm hole if the fixing specifies
6mm.
Yes, I rarely drill the specified size hole, always a bit smaller. My SDS drill box has drills (surprise!), a seletion of plugs *and* a small hammer for tapping them in. My idea of a correctly installed wall plug is one that needs to be tapped in gently.
I drill a smaller hole because the drill always seems to make a bigger hole that I expect due to some sideways "chatter" of the drill bit when I'm using the hammer action. And I agree: if the rawlplug goes in easily, the hole is a fraction too big.
Getting rawlplugs right is a bit of a black art in my experience. Either I make the hole slightly too big and the plug rotates in the wall as I tighten the screw. Or else the screw binds in the plug (presumably because the hole isn't big enough to let the plug expand) and I can't tighten it any further (spraying the screw with WD40 first helps to lessen this). That's using the screws that came with the plugs, so presumably they *are* the correct size.
Getting oversize holes could be due to a bent drill, worn drill chuck, play in the motor shaft (dodgy bearing) or if an SDS drill a worn tool holder. As for wall plugs turning in the wall that could be down to incorrect plug for the material. The red, yellow and brown plugs (Rawl plug types and derv itives) these are not universal plugs, though commonly used and work in man y situations they do have their limitations. Aerated concrete blocks are th e worst for drilling and plugging, if you can get a fix the first time, und oing the screw and screwing back up the second time inevitably does not wor k. Fischer do the only one I ever found that secures well to aerated concre te, the plug has slow helical vanes and the plug is hammered in after drill ing a pilot hole. I used these in the extension of our last house which had aerated concrete inner walls to hang kitchen cupboards and radiators and n ever had a failure. Our present bungalow has cinder type breeze blocks agai n I have not had issues with having to drill undersized holes or plugs turn ing.
Richard
I remember my dad using Rawlplastic -- very useful for holes that turned out too big (or conical). I wonder if you can still get it? No, full of asbestos.
I think mine suffers from *all* of that, plus being held by a weedy fellow with arm wobble for the hammer recoil. Remarkable sometimes that there still is a wall standing nevermind overlarge holes!
I'll be shopping for a new drill, me thinks.
I've had a couple of bricks fall out when I've been sinking socket boxes and found myself looking into the next room, especially when the originals were mounted back to back for cheapness.
Owain
I remember my dad using a Rawltool to make the holes!
I've still got about 1/3 of a tin left. Do you want it?
I think I've still got one or two of them! I don't think I ever used them, though I can (like you) remember my father using them.
I've still got one, and sometimes (rarely) use it when ICBA to go and get a drill and it happens to be in the tool box.
I was always seriously impressed by how well those work -- to the point where I recently (probably means 25 years ago...) went searching and bought one for myself. Often easier than usng a drill at the top of a ladder. Certainly easier than using a corded drill with an extension lead at the top of a ladder.
Yes! No, no I mustn't. But thanks.
Exactly the same as you. Not just with SDS, I do the same with my mains and cordless hammer drills.
I still do occasionally. It's hard work, but it'll drill anything.
Perhaps I ought to buy an SDS. But I need to build the workshop first.
Andy
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