pocket screws in boat building?

[DeniseO30]

Yes?

No?

Maybe?

Or is it sinfully wrong to think of using them?

Please don't hate me, just doing some thinking with my fingertips!

[TerryLL]

So, what are you connecting to what that you would need pocket screws?

[Dale Genther]

Forgive me if this is a dumb question. What is a pocket screw ??

[rbgarr]

They could be useful for drawers just as they can be for "land furniture". Remember that one consideration in boat building is that it's useful to be able to dismantle parts for refinishing and repair. The marine (salt water at least) environment is hard on finishes and strains on wood elements are greater than something sitting at rest in a house.

[David G]

Forgive me if this is a dumb question. What is a pocket screw ??

Don't be silly. It's a fastener specially designed to keep the valuable detritus from falling out of your pockets in the event of a capsize. This is accomplished by using pocket screws to attach your khakis to your strong, secure, pelvic bone

Actually, its part of a fastening system which includes an angled jig to drill holes in the backside of one member which is to be fastened with screws to another member. The most common are made by Kreg:

http://www.kregtool.com/index.php

To answer the original question: there's nothing inherently wrong with using pocket screws in appropriate marine applications.

Two caveats though: First, use the stainless steel screws available from McFeeley & others

http://www.mcfeelys.com/pocket-hole-screws

Second, keep in mind that this joint - which amounts to a reinforced butt-joint - is not very strong when stressed in certain directions.


"After the last of 16 mounting screws has been removed from an access cover, it will be discovered that the wrong access cover has been removed" -- De La Lastra's Law

[Tom Robb]

It's hard to imagine a part on a boat that would work with them. They aren't much use in any structural bits. Perhaps face frames? The screws aren't corrosion resistant are they? One of the wood mags (Fine WW?) did a test on various glued joinery methods. IIRC the pocket screws were way down on the effectiveness list. Oddly the half lap won the test - lots of glue surface.
Where would you think they might go on a boat?

[Dale Genther]

Ahh, now I know what they are, never know the real name for them. I'd say they were OK for drawers, interior joinerwork, etc. Use SS fasteners. But why? There are better, nicer looking, and more entertaining ways of attaching pieces of wood together. Personally when I see them I think "cheap"

[ron ll]

Depending on their orientation, seems like they could be a great place to trap water against open grain.

[JimConlin]

They're certainly an efficient way to do face frames in home cabinetry.
Maybe you could use them for some joinery on larger power boats particularly. Use the SS screws.

[James McMullen]

The kreg jig and pockethole screw is the slickest little doo-dad for making face-frame kitchen cabinets. I've used it quite a bit in that application. But for boats. . . . .

I sometimes use the specialized "pocket hole screw" to hold things together as a temporary clamp until the epoxy cures as they are specifically designed to draw the pieces together better than a garden variety screw. Then I back them out and plug the hole.

The screws are way too rust prone and the joint is not sufficiently strong enough to use them any where permanently in a boat's structure I think. Maybe in the kitchen of one of those three-story tall, fat-assed marina queens that uses standard house furniture, but not in the galley of an actual seaboat.

[DeniseO30]

Hey James.. I stopped by Lowes today picked up a Kreg. Your right! It's slick! Having 2 cordless drills is even slicker.. more slick.. slickerer, err.. cool I can see it's clamping power is going to be very useful! I know what is going to hold the station molds in place now!

[MiddleAgesMan]

Face frames assembled with glue and pocket screws are probably the strongest you could make. Many years ago we were delivering cabinets to a job using an open stake bodied truck. One wall cabinet was loaded at the very top but no one thought to run a strap across it. When we encountered a stretch of road where the speed limit got up to about 50 that cabinet was lifted right off and went flying. Our driver saw it in the mirror and pulled over to retrieve the cabinet--in two pieces. The frame had separated from the carcass but none of the joints had failed. The installer was able to install the cabinet, re-attaching the frame. There was one ding in a corner but trim covered that up.

The beauty of pocket screws in face frame assembly is the instant strength you get from the screws and the continual clamping pressure they provide while the glue dries. None of the traditional methods can come close in a production environment.

[David G]

Just keep in mind to use the Stainless Steel screws when you use this joint in a marine application. It's also true - as previously mentioned - that the resulting pockets can be a perfect moisture trap. The Kreg folks have that covered, however. If you look at the website I linked to before, you'll see that they also sell bungs in a variety of woods.

A bit about strength. Fine Woodworking recently did a test of a variety of frame corner joints being subjected to Racking Stress. This is the angle of load where such a joint is weakest. The results: pocket screws were stronger than doweled joints, domino joint, butt joint, miter joint, and many others. About midway up the list, but probably the simplest of all to execute. The strongest joints were splined miters and bridle joints (open mortise and tenon) where the tenon was 3/8" in 3/4" stock.


"As a general rule the most successful man in life is the man who has the best information" -- Benjamin Disraeli

[Captain Blight]

The problem with the Kreg system is that it locks two pieces of wood at 90 degrees to each other. Now how often do you see that on a boat?

[David G]

The problem with the Kreg system is that it locks two pieces of wood at 90 degrees to each other. Now how often do you see that on a boat?

That is the most common usage - like in face frames. However, pocket screws can be used to connect two pieces of wood together at a wide range of angles. If you look over their website, I bet you'll see a sampling of the kinds of things that are possible. Or... just use your imagination. It's not at all uncommon in furniture work to pocket screw oversized members together at some compound angle and then machine and/or carve them into some final shape that doesn't look at all like a Face Frame. Another example... pocket screws can be used to fasten staves together side-to-side, as in coopered work.

[DeniseO30]

Funny 2 weeks ago I made a tiger maple frame for a mirror to dress up the head of my Oday I used splines on the miter joints. Coulda used the Kreg!