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.

  • fondue@lemmy.world
    0·
    3 hours ago

    It is a sleeve expansion bolt, sleeve is designed to blow out effectively into the material as the bolt tightens, so I think in general these are somewhat destructive, permanent fixtures. II think most of the time to fully remove requires a re-drill with a larger bit, so you could re-drill and then patch/fill. They can withstand crazy loads/force. Overkill for a bike, but would def work as a permanent solution - not what I would go for.

    Sure you want to keep hat nice floating effect, minimal aesthetic. Those plastic insert sleeves should be fine if the hole is drilled precisely. You should blow out the bore hole to remove debris. You could glue the insert into the masonry, let that fully cure, and then drive the screws to get better expansion. Screws would be removable, but the plastic sleeve wouldn’t be. Good luck.