I've been dealing with a problem where standard screws keep getting pulled out of a wood frame. I know there are options, but it got me thinking:

Are there such things as screws that have "oversized" threadform? (if so, what are they called?)

From my research, I could get a little extra 'bite' by using sharp V threads. Most threads seem to be between .60-.75 pitch, but is there something on the scale of 1.5 pitch?

Is threading that large not practical because it would require so much force to drive?

Or would the material of the thread not be strong enough to add any practical gripping power?

  • 1
    While we've helped you identify a screw type, it seems that it might be better to pursue the cause of your screw pops. You may want to post a new question describing your problem and look for a solution there. Include the type & size of wood, the type of joint (end v face grain), the type & size of screw, etc. Also, define "frame" are you talking delicate picture frame, or waterbed frame - there's some difference! – FreeMan Jun 3 '16 at 13:55

I've been dealing with a problem where standard screws keep getting pulled out of a wood frame.

Even with options on screws I think the first thing you should look at is why are your current screws pulling free? It sounds like there's an issue with one or more of the following:

A) the wood being too weak (in which case no screw of reasonable gauge may hold successfully)
B) the load is too high for the number of fasteners (if possible increase the number to spread the load)
C) the pilot holes were drilled too large

A and B can be linked, so a fix for A can mean that the existing number of screws will be sufficient now that they have a firmer hold.

Regardless of whether C was the case initially since you've already had screws pull free I think we can assume you have stripped holes, which means you have to go up a gauge or two in screw size and/or repair the existing holes before driving in new fasteners (see Loose screws in this previous Answer).

If your wood doesn't have the strength to support conventional wood screws then one of the fixes for a stripped hole can be used to provide a more secure hold, including drilling out for a glued-in hardwood dowel or wooden plug (note: only drive screws home after the glue has fully cured). In addition to inserting dowels or plugs where the screws will go dowels can also be installed at 90° to the screw's axis. When driven home the screw then bites into the side of the dowel (long grain) which provides a very much stronger hold if it is going into end grain. This is often done if strength is important:

Dowel to secure screw in end grain

Are there such things as screws that have "oversized" threadform? (if so, what are they called?)

Coach screws can have larger threading in comparison with a typical wood screw, although this does tend to go hand in hand with them being quite beefy. Many would to too large or ugly for some applications. Although there is some variation they typically look like this:

Coach screw

Many modern deck screws also have larger threading (or twinned threads).

Most threads seem to be between .60-.75 pitch, but is there something on the scale of 1.5 pitch?

Machine screws have a lower pitch. Although they also have a very shallow threading usually if they fit their hole well they can have an extremely good hold in wood (hardwood in particular). Two reasons they're not more widely used is that they're slow to drive and the head style is usually not what we're looking for.

Or would the material of the thread not be strong enough to add any practical gripping power?

The wood is nearly always going to be the weak point here. It's the threading in the wood that may not be strong enough as it's created partially or wholly by crushing of fibres. There's little fear of the thread on the screw itself stripping off unless it's been damaged, e.g. by corrosion. But even at that I've pulled heavily rusted screws and bolts from wood numerous times and the threading usually remained intact!

  • Thanks for a great answer @Graphus. The problem is actually screws holding a door damper to the door frame. I'm pretty sure that the wood is of insufficient quality/density for the job it's doing. The options for fixing are limited unless I want to open the wall and work from the other side as well, but all of that is tangental to the question. – micker Jun 4 '16 at 20:00

As mentioned above, Confirmat is made to handle mdf/particle board where screws tend to pull out.

A walk down the aisle will show all sorts of screws including what seems like a lot of new types. Depending on overall need, I like the course "drywall" screws, but be aware they are much more brittle than normal wood screws. "Decking" screws seem to be a good mix of thread and steel properties for a lot of applications.

Like the Epoxy suggestion, CA cyanoacrylate(?) glue will support the threads, and is used when threading a turned wooden box to keep the threads from crumbling.

  • +1 for decking screws, though they're a bit long for some applications, and the OD might not be much bigger than you had to start with. They certainly have a deep thread. – Chris H Jun 2 '16 at 16:32

There are Confirmat screws that are made for screwing into particle board. I am not sure how well these would work in normal wood. Confirmat screw

Screws in general don't hold nearly as well when screwed into end grain as they do into face or edge grain. It is for this reason that people use pocket holes for this type of connection. If the wood around the threads has been damaged, you can drill it out and plug it with a glued in plug that fits tightly, then screw into the plug.

You can also reinforce the wood around the threads with epoxy. To do this, drive the screw as normal, then remove the screw and fill the hole with a thin epoxy, then reinsert the screw. The epoxy will strengthen the wood fibers around the threads.

  • With the plug you can also orient the grain differently so the screw can hold better than in endgrain. – ratchet freak Jun 2 '16 at 14:29
  • @LeeG I agree, without a sharp tip, it probably doesn't drive very well into normal wood. There would probably have to drill two pilot holes (one for threaded portion, one for shaft). Ideally, I would use a bolt with some washers to help increase the surface area, but that isn't really a great option in this case (no access to other side of frame). – micker Jun 2 '16 at 15:27
  • The downside of the epoxy method is that you're unlikely to be able to remove the screw in the future. – Chris H Jun 2 '16 at 16:35
  • One pilot hole could work, but it would have to be just the right size. – Chris H Jun 2 '16 at 16:35
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    @micker, for most screws you should have two drilled holes in fact, not just one. The first is a clearance hole, the second is the true pilot hole. See Conventional screw use in this previous Answer for more detail. – Graphus Jun 3 '16 at 8:37

Yes, I have had screws that had some huge threads. But because I never look for them I do not know how common they are.

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    While this does, technically answer the question ("yes"), it doesn't really provide much useful information. – FreeMan Jun 3 '16 at 13:59

I agree with you about the need for a deep thread screw. The euro screw does have a wider thread. Here's a picture of one: https://www.ebay.com/itm/HSI-Euro-Screws-Nickel-Plated-Iron-6-3-x-11-mm-Pack-of-50-656164-0/152795824778?hash=item239357428a:g:iCAAAOSwYwJaE0E4 They are often used in cabinetry making and come in half inch to two inch sizes from what I have seen.

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