I have this kind of anchors (plugs): rawlplug uno

Despite googling hard, I couldn't understand what type of screws they should go with: wood screws? sheet metal screws? machine screws? coarse thread? fine thread?

Every source seems to only specify the diameter and length of the screw to use with a particular size of the plug, nothing else!

Also, if there is any other feature of a screw relevant to their coupling with a given anchor, I'd be interested to hear about that.


2 Answers 2


Plastic wall plugs are designed for use with wood screws. The wood screw cuts its own thread and is tapered allowing it to expand the plug and make it grip the masonary.

Note that while those plugs are "universal" in the sense that the manufacturer says they can be used in both solid and hollow walls, their load bearing capability in a hollow wall is far lower than in a solid wall because there is much less for them to grip.

  • Thank you. Strange that such basic information is not easily found on google. It's like assumed that anybody would inherently know :(
    – anon
    Nov 7, 2019 at 10:48

Normally a wood screw, but a sheet metal screw would also work. a national course /fine thread won’t grab the plastic and will easily pull out. The type of head matters in some cases like a flat head that sits in a beveled or counter sunk hole, a button head more common. Hope that helps

  • Thank you. By "national course" you are referring to the Unified Thread Standard, aren't you? Anyway, I am a bit confused by what that means in your comment. In this context, is that a synonym for a machine screw?
    – anon
    Nov 7, 2019 at 10:49
  • 1
    Yes for example a # 10 screw comes in 24 or 32 threads per inch this is corse and fine both wood and sheet metal screws work fine with these plugs.
    – Ed Beal
    Nov 7, 2019 at 14:03

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