Screws in old wood?

[Mike Holbrook]

I have two pieces of furniture, desk & file cabinet, from the mid to late 18th century, probably not valuable but I like them and want to use them. Some of the old single slot scews in these pieces appear to be rusted and are not holding. I am thinking about replacing them with newer screws or some sort and trying to reinforce the wood they need to hold in. I am wondering what type screws might appear natural and how I might improve their ability to hold?

[Phil Mueller]

If the screw's slot and thread are in decent shape, I would soak them in Vinegar or vapo-rust and clean them up. Then to shore up the wood, I would glue in a dowel or multiple toothpicks (depending on the size) to fill the hole so the screw will hold.

[Malcolm McLeod]

...What Phil said.

If screws are salvageable, remove them, drill the hole to a slightly larger standard dowel size, glue in a dowel 'filler', then re-drill a pilot hole for the screws and re-install. Have done it a number of times on 'Ikeaesque' pieces in my college days.
Its end grain and perhaps not as strong as it could be, but its completely hidden.

[Jim Koepke]

This depends on how much work you want to do.

I used to save wooden match sticks for this purpose. Now a piece of scrap can be split with a chisel to make a hole tightener.

It may be easy to drill the area and glue in a dowel to repair the hole. Then drill a new pilot for a screw.

Save the old screws for show or reuse them. It is up to you.

jtk

[Daniel Rode]

tooth picks, stick matches, golf tees.

[Tom M King]

I was working on the entry doors to an 1850 house this week. The hinges do not come apart, so I had to take the screws out to take the doors down. They look like normal straight slot number 12s, except the screw part is not tapered, and the ends aren't pointed. They are still holding just fine, and I like the design. I have some pictures in the camera to post later. Another interesting thing that I haven't seen is that the panel has Beaver fur packed around it in the slot-I guess for weatherproofing. The one big panel had shrunk enough to be one-sided, and I needed to center it back up. I found the Beaver fur when digging old paint and caulking out of the gapped side. It may have been felted or partially felted to start with. I typically use Heart Pine and epoxy to fill holes and redrill if needed.

[Malcolm McLeod]

Tom's comment about 'non-taper' made me think of Confirmat screws. If wood is still sound, it might be quick/dirty fix - - if you can deal with the old vs. new heads exposed.

[Mike Holbrook]

Thanks for the replies. The old file cabinet has lots of screws in the drawers & cabinet. The fronts of the file drawers are about 3/4" the backs are about 5/8"and the sides are around 3/8", all solid wood joined with dovetail and finger joints. Obviously some of these screws have been replaced over the years. It looks like the original screws were single slot round heads around 1/4". There are some newer slightly larger round headed screws and some that appear to be more modern larger phillips head screws. None of the screws appear to have any kind of resistance to rust or corrosion, although I guess some of the screws could be brass and just tarnished. Most of these screws will not normally be visible, unless someone pulls a file drawer all the way out.

I was wondering if the screws rusting was weakening the wood, particularly where the screws thread into the wood. It looks like the old small screws in the back of the file cabinets have been pulling out. There are also some screws inside the file cabinet that have given out due to having to support too much weight or being vibrated because they hold moving parts. It sounds like everyone is suggesting various ways to replace or reinforce the wood with other wood. I suppose I could drill holes for some of the 3/8" dowels I have lying around, or I could saw a small piece out of the side in bad cases and glue/clamp another piece in.

[george wilson]

They did not use brass wood screws in the 18th. C. to my knowledge. Their brass was cast,and easily wrung off if used for screws. When I first came to work in the museum,I thought it was peculiar and rather ugly to see iron screws in brass hinges. By now,I think it looks messed up to see brass screws in brass hinges!

When I make boxes,the best thing to do is polish with hand buffs and fire blue the screws with a torch before using them on polished brass hinges. That was the ne plus ultra in the 18th. C..

[Malcolm McLeod]

...probably not valuable but...


Mike,
My occasional foray into public television is mostly to watch "Antiques Roadshow". If you're innocent of such frivolity, there is a typical scene where visitor presents prized antique furniture, reviewer raves over it's 2nd century perfection, announces it's worth X dollars as-is. "BUT ..... you refinished it, didn't you? If you'd left it alone, it would be worth 10X dollars!" Oops. (Only reason I watch the show.)

You might check with antiques expert before you perform a simple, but potentially expensive surgery? Just in case.

[James W Glenn]

If I was not concerned with erasing part of the archaeological record or the "Road Show" value, I would clean up up the original screws and "pot bolt" them in the original holes with an epoxy. I would use a structural filler like colloidal silica with enough sawdust to get a reasonable color match, mask every thing, wax the screw, hardware and the surface of the wood under the hardware. Then I would fill the holes with just enough to fill in the gaps and assemble every thing. When the epoxy is partially cured "green" the screws are backed off to break the bond. That way everything can be taken apart if necessary in the future.

[Mike Holbrook]

George and James, great suggestions. I may try several of those ideas and see what works best.

My wife watches antique road show on occasion so I am aware of how restoring antique items can devalue them. I like both pieces though and making them more functional is more important to me than retaining value as antiques.

[Karl Andersson]

Mike,
I think you might have meant "mid to late 1800s", not 18th century - if it is indeed a file cabinet, as in vertical files, they weren't really in use (or invented) until the late 1800s/ early 1900s. But the good news is, you don't have to worry about being "that guy" on Antiques Roadshow who restored the wrong antique - I'm sure your desk and file cabinet have value, but not the crazy value like the pieces that MUST have patina in place do. So, with an eye to keeping the external finish as original and intact as possible, fix it up and enjoy it, and don't worry too much about harming the value - a file cabinet is really only worth something if the drawers work.

The only thing I would add is that for screws that are really weight/force-bearing, I use a plug cutter to get a fill piece with side-grain; I've had too many end-grain fixes fail after a short while on heavy-use screws. Something to look for - if it is an oak file cabinet, the reason for the failure may be the action of the wood's tannic acid on the screw and the screw may have to be replaced because it is corroded to a smaller size and can't bear the force needed any more. I've seen this on old oak pieces, especially where they were stored in damp areas (relegated to basements, attics, abandoned office buildings). The screws closer to the floor are usually the worst, so you could compare one of the "failed" ones to a screw from higher up just to make sure it's close to original size.
Karl