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cefreeman_gw

Old, brittle screws

CEFreeman
11 years ago

Ok.
Here I am again.

I'm trying to take the hardware off some antique doors. Needless to say they're held on with flat head screws.

The thing is, when I actually get a screw driver that fits the slot, when I try to turn it, one half of the screw head is just breaking off.

I'm working on the plates that go behind door knobs (forgot their name) and the strips along the edge of a door that would be an exterior door.

Any suggestions? Don't want to mar my beautiful doors.

Thanks.

Comments (5)

  • lazy_gardens
    11 years ago

    Drill them out. There are spacial drills for removing broken screws.

  • brickeyee
    11 years ago

    Sounds like very old brass screws.

    Are you using a correctly flat ground screwdriver?

    There should be no taper on the blade and it should fill the slot the narrow way and be as wide as the metal of the slot the long way.

    Even then, some old brass and steel screws are so weakened by corrosion and so tightly attached to the wood by corrosion they cannot be easily removed.

    There are smaller sizes of left hand screw extractors that might be able to get a bite into the screw.

    It might be worth using them from the start since with both sides present it will be a little easier to keep the centered.

    If you can get the hardware off you can core out whatever is left of the screw and glue in a wood plug for the next screw.

  • sombreuil_mongrel
    11 years ago

    Heat can get them moving, but if all the heads are broken, it was probably a bad batch of screws from the factory.
    A large soldering iron will apply heat to break the rust bond to the wood.
    Casey

  • CEFreeman
    Original Author
    11 years ago

    They're definitely brass. The few that come out are nice and solid.

    I'll try the heat first (thanks, Casey) then I'll look for these screw extractors.

    I have present-day flat-heads, which I see are more tapered, rather than square to the slot. The slot doesn't seem deep, although I did pick crap out of the slot with a safety pin.

    Thanks all.

  • brickeyee
    11 years ago

    "I have present-day flat-heads, which I see are more tapered.."

    Must be cheap Chinese screws.

    The slot is supposed to be square and flat on the bottom.

    Keep in mind if you want to use the holes again you will likely need longer or larger diameter screws that may not fit countersinks in the hardware without some modifications.

    If the hardware is going for a new use, make sure you drive a steel screw almost tight before replacing it with a brass screw of the same size.

    I keep a matching steel screw in every box of brass screws for cutting in the treads and sizing the hole.

    Brass is not strong enough for a correctly sized new hole, especially in harder woods.

    If you make the hole large enough you lose a lot of the strength of the screw attachment in all but the softest of woods.