Using drywall screws for woodworking

[David Nebenzahl]

Link to a good article posted in another newsgroup:

I'm pretty "old school" and something of a purist, and don't like to use these other for their intended purpose (securing drywall to framing), but I'll admit that I've grabbed them and used them a time or three for other things.

Discussion in other ng was about coarse vs. fine threads: consensus seems to be that coarse threads are better in wood.

Didja know that the fine-thread screws were originally made for putting up drywall on metal framing? I didn't.

[Chris Friesen]

Drywall screws are prone to snapping off the heads if torqued too much in hardwood.

I generally use coarse-thread lo-root assembly screws. They're very much like drywall screws in that they have sharp threads, but they're designed for woodworking.

These Robertson-brand screws are good. Far superior to the flooring and decking screws at the Borg. They also come in self-drilling versions:

Spax screws are excellent but expensive. They really are easier to drive:

[Lew Hodgett]

--------------------------------- Use coarse thread deck/drywall screws strictly for temporary applications such as one time jigs, forms, etc.

For wood working, use S/S coarse thread, self tapping sheet metal screws along with a 75% of thread OD pilot drill.

Don't twist off any heads and haven't had a fastener come loose yet.

Lew

[Puckdropper]

David Nebenzahl wrote in news:4bc4eb8e$0$2379$ [e-mail]:

I use them all the time. They hold extremely well, and I haven't had one snap on me in a long time. Perhaps it's due to the impact driver hammering the screw instead of just twisting it. The drywall screw heads fit the DeWalt #2 Phillips head perfectly, so there's no slippage when driving them in.

When screwing into plywood, the fine thread screws may work better. However, when screwing boards together the coarse screws are far superior to the fine threads. The fine threads strip out extremely easily, especially in pine.

The guy mentioned that wood screws don't have the threads all the way up, so they pull the boards together. The simple solution to this is simply to drill a larger pilot hole. The pilot hole is there to prevent the wood from splitting, so as long as it's sufficiently smaller than the screw head it'll still do it's job.

Puckdropper

[Chris Friesen]

I'm curious about your rationale...

1) Why S/S unless it's in a damp location? They're way more expensive and harder to find. 2) Why sheet metal screws? Aren't they normally threaded the full length? 3) The scientific literature suggests the pilot hole should be 75% of the root diameter in low density woods and up to 100% of the root diameter in high density woods. Technically the outer thread diameter doesn't matter.

Chris

[Chris Friesen]

While that's one reason for it, a suitably sized pilot hole will actually increase the strength of the joint. A pilot hole that is too small results in crushed wood fibers which have less structural strength.

Chris

[dpb]

Chris Friesen wrote: ...

Why for Lew I don't know but I use them because they have more aggressive threads and drive much easier than traditional wood screw.

Habit developed before there was nearly as much choice as now.

Still use traditional methods where seems appropriate to do so...

--

[SonomaProducts.com]

I'm sure there is some sort of sexual joke hanging out there but I'll just let it pass.

[Lew Hodgett]

------------------------------------- Standardization.

I buy fasteners buy the box so S/S are available at a modest premium.

S/S are readily available locally here in SoCal as well as from people like Jamestown distributors.

The cost of fasteners gets lost in the wash compared to piece of mind knowing I'm not going to grab the wrong fastener, especially in a marine application.

Self tapping screws are threaded full length, NBD.

Their coarse thread bites into the wood easily and engages fully.

Lew

[dadiOH]

You also want the bugle head. Flat head wood screws don't dimple like they do.