I used a 10mm masonry bit to drill for a 10mm plastic anchor like that pictured. The anchor spins freely in the hole, which I think is expected. I thought I read somewhere that the screw size should be 2mm less than the anchor. Thus 8mm for a 10mm ø anchor. But an 8mm screw is fat enough to rub sides of the anchor as it is inserted because I suppose the anchor is only 1mm thick at the opening. The guy at the shop confirmed that 8mm is too big. He said a 6mm screw matches and sold me those. After installing and loading, the anchor started to pull out.
Do I need a 7mm ø screw? Odd sizes get decreasingly common above 5mm. Yet 10mm sleeves are very common… so it’s not adding up.
I would like to have a reliable PDF chart of bore,anchor, and screw sizes – in metric. It seems there are plenty of such charts for Imperial/English units, like these:
- http://nfaspace.com/services/Forms_files/Anchor Classification Guide.pdf
- https://anchors.dewalt.com/anchors/_documents/uploads/DWANF_ICDWANCHSG_r01.pdf?1659150839
I’m not sure what a “#10” screw or anchor is. Does that refer to the metric size despite being in an imperial system.
Youre right about the wings.
Youre right the thing shouldn’t spin.
Why were you drilling if it’s an existing hole? You’re using a masonry bit with a hammer setting right?
I wouldn’t re-use this thing. This is the cheap type that comes free with things that need to be fixed to a wall.
Get a new plug matched to the hole and a new screw matched to the plug.
It was not a freshly drilled hole. I would always use the same size bit as the anchor diameter so I remembered that. A 10mm anchor in a 12mm hole would also be very loose which is not the case here.
I just now drilled a bit more after realising that the anchor should probably be flush with the brick, not the 10mm of plaster layered on top of it.
Yeah, and in fact it’s not just a hand drill with a hammer setting but a proper ~10kg hammer drill with a shock absorber, a grease reservoir, and STS mounted bits (or whatever they are called). Before I bought this big gear that makes me feel like Rambo, I used a standard drill with hammer setting on poured concrete and it melted one of my bits because it had a weak hammer and spun fast enough to make the bit molten red hot.
Maybe too late to change now but I might consider a different anchor if it fails to hold my bicycle. I ended up drilling 10mm deeper so that I could push the anchor to be flush with the brick (thus 10mm recessed below the plaster layer). I also added a metal shard about the size of a toothpick between the anchor and brick. It’s holding for now but does not feel rock-solid.
Yeah, that type of plug in particular is really flimsy, just but some new ones that are a bit more sturdy