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I am working on a desk picture frame made of white oak, and I have a hinge and some turn buttons that included brass plated screws in the package. (I am assuming they are plated because they are attracted strongly by magnets. I don't have any exact details about their materials.) I am aware that oak is especially susceptible to the tannins reacting with with iron to produce black staining. I would like the piece to last for a long time so I'd like to get some opinions on the matter.

Should I be concerned about using inexpensive brass plated screws from a tannin stain perspective? I have no idea what the plating thickness is or whether it would get rubbed off from friction during driving.

If brass plated is an issue, I would appreciate some advice on alternatives. The alternatives I am aware of are...

  • Solid brass - Weak/prone to snapping? I am mainly concerned if the recipient has to adjust the turn button pressure and it snaps in the hole, but I guess the threads would already be cut in the wood at that point.
  • Silicon bronze - Seems tricky to get in #2 3/8" size, and color doesn't match other hardware
  • Stainless - Color doesn't match other hardware

Thanks!

  • Yes. If I were able to I'd love to have put that as an Answer :-) – Graphus Aug 30 '18 at 14:04
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    Now re. iron stains in oak, this isn't quite the problem it can be perceived to be. For a start it depends on the tannin levels in the oak, and some oak is actually fairly low in tannic acid (by the standards of oak) so isn't particularly prone to it. But the main thing is the staining occurs with iron in the presence of water. If your wood is well dried, the norm for most hardwoods these days and particularly so in America, and will spend its life in a typical domestic setting (again esp. in the US) there's almost no potential for iron staining to occur. – Graphus Aug 30 '18 at 14:11
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Solid brass screws will be plenty strong enough for all the parts of a picture frame I've ever encountered.

The key (assuming these are wood screws or sheet-metal screws, not machine screws) is to predrill the right size pilot hole. The pilot hole should be the same size as the root diameter of the screw, the root being the solid part in the middle that's not the threads. If you think of a wood screw as a nail with threads wrapped around it, the root diameter is the diameter of the nail.

If the root is not exactly some 1/64th of an inch, go to the next 1/64th down.

This pilot hole will make turning in the screw much easier and in fact makes its pull-out strength considerably greater.

Anything plated becomes un-plated, and usually sooner rather than later. No need to count on luck here, just toss the original screws and get some solid brass ones at the hardware store or online.

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    You might want to add the common tips relating to using brass screws, especially small ones — driving in a matching steel screw to thread the wood in advance (good hinge sets with solid brass screws will include a steel screw of the same size for precisely this purpose), and lubricating the brass screw. After doing the first the second may be overkill, but it can't hurt and takes only a moment. – Graphus Aug 30 '18 at 14:15

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