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:

I’m not sure what a “#10” screw or anchor is. Does that refer to the metric size despite being in an imperial system.

  • diyrebel@lemmy.dbzer0.comOPEnglish
    0·
    7 hours ago

    Sounds like chemical anchor, which is a 2-component epoxy. I used that when installing anchors on my roof to use for abseiling. Did that because my life depended on it. But otherwise I try to avoid chemical anchors indoors because they cannot be removed later. I could get out an angle grinder at that point, but there may be a day when I decide to remove all the render to expose the natural brick, in which case the anchor would always be an eyesore.

    Otherwise I quite like chemical anchors because there is less stress on the wall, and yet they are stronger than mechanical anchors.