CarpentryFilter! How do I re-anchor a wood screw that's been pulled out of a bedframe?

February 19, 2006 12:48 PM

The side rails on our wooden bed frame attach by hooking into a metal plate screwed into a recess in the headboard. We didn't assemble things snugly enough when we first put the bed together and as a result one of the screws on the metal plate eventually levered out of the wood. How do we repair this?

We've gotten replacements for all the damaged parts but since the original screw was pulled right out of the wood there's nothing there for the new screw to get a purchase on. There are a lot of things I can think of to try but if the repair fails I'll have even less of the original wood to work with the next time around so I need to get this right the first time. The weight of the bed is carried by the metal bracket in the recess, so any forces on the replacement screw (from leaning back on the headboard, for example) will be trying to pull it right back out again.

What's the most structurally sound solution to this problem?

posted by Lazlo to home & garden (9 comments total)

Try filling the hole with wood glue, let it dry, screw the screw in. It could be difficult to get a thick glue into a small hole, however. If that is the case, you can put a matchstick or toothpick (or larger stick or something, depending on size of the hole) in the hole and break it off in there, providing something for the screw to get purchase.
posted by theperfectcrime at 12:57 PM on February 19, 2006

Some choices:

1) Get a bolt long enough to go entirely through the wooden headboard. Get two washers, with internal diameter the same as the bolt and external diameter considerably larger. Get a nut, with internal diameter the same as the bolt. Thread bolt through washer, through headboard, through metal plate, through washer, and screw on the nut, tightly. This may be tricky, since the bolt may interfere with the installation of the side rail. It may also be somewhat ugly, though the headboard is probably against the wall so it doesn't really matter. However, it would definitely be strong.

2) There are little things you can cram in there with the screw, in effect expanding its diameter so that it grabs the intact wood around the screwhole. Something like this. Ask at your hardware store. You could also try the plastic sleeves for drywall screws, the idea is the same. And you could try filling the hole with wood glue, screwing it in, and letting it set really well (two days, there's little air in the hole to help it set) before putting any weight on it. These would not have compatibility problems, but I don't know how strong they would be.
posted by jellicle at 1:08 PM on February 19, 2006

Get dowel pins 2-3 times the size of the enlarged hole, say 3/8 or 1/2". Hardwood preferred. Drill out the enlarged hole to match your dowels. Glue dowels into bed frame, wait to dry. Drill pilot hole for your screws in dowel. Assemble.

If you have access to the inside of the frame and can drill a hole with out it being noticeable inserting a dowel cross ways to the screw after you plug the original hole is worth doing. It'll be significantly stronger.
posted by Mitheral at 1:21 PM on February 19, 2006

E-Z Lok threaded inserts are designed to solve your problem, permanently.
posted by paulsc at 1:24 PM on February 19, 2006

Mitheral has it. A glued dowel is amazingly strong. You can buy a package of short pieces of doweling, or you can buy a dowel rod of about 24 or 30 inches at a hardware store. With a hacksaw, cut the length that you need. The glue you want is called wood glue.

When gluing a dowel, I notch the sides to add gripping power. There's nothing to it; just use a utility knife or razor blade and cut several horizontal or diagonal ridges (deep scratches, really) into the wood. Some pre-cut dowels already have ridges. They prevent too much glue squeeze-out.

After letting your glue cure, make sure to drill a pilot hole before putting the screw in. And the longer the screw, the stronger it'll hold.

As for the cross-ways dowel, I'd say it's optional.
posted by wryly at 1:46 PM on February 19, 2006

The wood dowel repair isn’t particularly robust, because you will end up sending the screw into end grain rather than side grain. Nails don’t hold well in end grain and screws do only a little better. In order to visualize the problem, get a screw and an ordinary pocket comb. If you run the screw into the flat side of the comb, the threads grab the teeth and its almost impossible to just pull it straight out... that’s side grain. If you hold the comb narrow edge on the screw just spreads the teeth and slips in and out... that’s end grain.

The best solution might be a steel Zip-it anchor. These things are sold at Lowes and Home Depot and are generally used as screw anchors in drywall. They have internal threads that accept standard wood screws. If you’re installing one in sheet-rock, you use a cordless drill and zip it right in. In wood you would need to drill maybe a 1/8" to 3/16" (depending on the relative hardness of the wood) undersize hole and use a cordless drill to zip it right in. In the unlikely event that your pilot hole is too small and the Zip-it splits the wood, just leave it in until you can work some wood glue into the cracks... then zip it back out, let the glue set for 24 hours, drill a slightly larger hole and try again.
posted by Huplescat at 5:01 PM on February 19, 2006

On further consideration: a Zip-it will probably be harder to get right than the original screw. You will need a #3 phillips driver bit and a good strong drill. Take care to push straight in and push hard. This solution would work best for very soft wood (that you can dent with a fingernail) like douglas fir. In that case drill a 3/8" pilot hole. In harder woods, drill a larger hole. Run the thing in first to see if it fits, then back it out and fill it up with a slow setting epoxy all the way to the top of the threads and run it back in. The threads will bite into the wood to keep it from pulling out and the epoxy will keep it from wobbling.
posted by Huplescat at 6:25 PM on February 19, 2006

The dowel approach works fine with door hinges and should work fine in this case. If you create a careful join between the dowel and the headboard, then use a screw that is slightly longer and thicker than the original, you should have a fit that will stay snug for many years.

You're right about the cause probably being an original loose assembly; a tighter assembly would not have created the same forces on the bracket/headboard join. If it's snug, the metal bracket will actually have some "give" (that is the metal will be forced to bend) and thereby dissipate the force that otherwise concentrated itself on pulling out that one screw.

The reason you don't need to worry about the end grain of the dowel here (although Huplestat has a good point) is that it's contained within the other wood. The force that would split the dowel ends up transferred into the headboard in all directions, and the screw holds in place.

Mitheral is also correct -- the cross dowel approach is a way to improve the strength. A lot of IKEA-type furniture uses such a cross connection, where the screw goes into a metal dowel, and the "pull" is then spread across the length of the dowel instead of across the thin edges of the screw.

Another optional strengthener would be L-brackets on the top of the sideboard attaching to the headboard, if you have enough room to screw them in. This will again stiffen eht entire structure and prevent the flexing that creates stress, and the visible screws will be something you can keep an eye on if they begin to work loose -- and if they break out in the same way you'll have a warning before the sideboards themselves go.
posted by dhartung at 8:23 PM on February 19, 2006

OK, I defer to Mitheral and Dhartung... the dowel solution will be a lot easier to implement, and will probably be just fine. In the interest of full disclosure, I carry a selection of dowel rods and a bag of golf tees to repair screw holes, and would only use the Zip-it alternative for the fussiest and most vindictive costumer imaginable... and maybe not even then.
posted by Huplescat at 3:55 PM on February 20, 2006