Adirondack assembly problems

[Michael Wildt]

Hi,

I've made the pieces for 2 Adirondack chairs in Mahogany a while back in a local woodworking class. Now that I finally find time to assemble them I'm running into problems.

The wood is roughly 1" thick for the slats and while using some test pieces I tried to screw them together using SS Deck #8 screws 2" long. I pre-drilled with a 11/64 tapered drill bit (from Rockler). Screw hole will be plugged with wood plugs.

When screwing the screw in it breaks the head off when it is almost seated. Other times it goes in ok. I'd hate to have screws fail on the chairs so I'm looking for a solution ahead of time.

The tapered bit only drills 1 3/4" so that leaves 1/4" for the screw to bite into. Would a longer drill bit solve this or should I find other screws or look into lubing the screw first ?

How about gluing the pieces together as well screwing. Would that be recommended ? I'd hate to have them get loose and then be unable to tighten due to the wood plugs.

Thanks,
Michael

[mike wacker]

Try lubing on some scrap pieces. Should do the trick. Also try GRK screws. They are very tough and have self cutting threads.

http://www.grkfasteners.com/en/R4_1_2_information.htm

[Mike Goetzke]

I recently built a cedar picnic table and had problems with a few SS heads breaking off too. I had the best luck with my impact driver.

I agree w/Mike W. about the lube. Also, since the fasteners are hidden maybe try some steel/coated deck screws. Stainless is not a strong as regular steel fasteners.

[Sean Kinn]

Lube should help, but I also found I had to be extra careful to drive the screw perfectly straight. If you have them off of straight just a hair it seems to be just enough to apply uneven force and snap them as they torque that final 1/8 of a turn (into a pre-countersunk hole). I also ended up hand tightening them the final turn or so to avoid any further frustration. Keep in mind for most spots that you use screws on the Adirondack chairs, they are just holding a slat or armrest in place and not necessarily taking a lot of the load. For these locations as long as the slat isn't rattling around excessive tightening of the screws isn't really necessary.

[J. Z. Guest]

Don't use tapered drills for deck screws. Tapered drill bits are designed for use with conventional wood screws.

Deck & drywall screws have threads that stand proud of the shank. Drill the pilot hole the same size as the shank or just a hair bigger. Then, the threads will bite into the wood. A straight bit is all that is necessary.

Wood screws have cut threads, so the threads are the same diameter as the shank under the head of the screw, and these work best with tapered drill bits or with two different size drill bits: one for the pilot hole and one for the larger diameter shank.

The Adirondack loveseat I just finished suggested glue & screws. The screws may loosen up over time with use of the chair, movement of the boards, etc. But the glue shouldn't.

[Peter Quadarella]

The best advice I can give is to use McFeelys wood screws, and glue. I had too much trouble with screws and finally switched to only using McFeeleys (and Kreg) and it has been a night and day difference. Glue is a good thing also. For outdoor, I would suggest Titebond III, although II would probably be fine also.

[Greg Hines, MD]

Whenever Norm makes an outdoor project like this, he always uses "Marine Adhesive Sealant" to glue the parts together. Sounds good enough for me.

Doc

[Cliff Rohrabacher]

When screwing the screw in it breaks the head off when it is almost seated.

If the screws are from the BORG there's a good chance they are inferior. Look to McFeely's for screws. I prefer the star drive: no cam out - ever - and they look cool.

Glue is a good idea. I would use titebond III or Epoxy depending on what you want to spend. Epoxy is of course repairable.

Unless you can clamp with tremendous pressure I'd not bother with Resourcinol.

[Michael Wildt]

Hi,

Thanks for the replies to my problem. The screws are called Grip Rite, got them at the local HW store (though the Borg seems to carry that brand as well). Seems pretty decent when used in other woods than Mahogany.

I'll try a regular 11/64 bit and some lube (soap bar).

Regarding glue. I'm unfamiliar with Marine adheasives but Titebond III hopefully will do the trick.

Thanks,
Michael