fastener depth

You should use the longest screws you can find that don't come out the other side. That being said, no matter what screws you use, 1/2" to 1/2" is going to be a weak fairly attachment no matter what screws you use. I'd certainly use glue in addition to screws and it would help to know where in your project are you joining 1/2" boards? Maybe it's a location that can be joined by other means.

For some reason I had it in my head that it was in fact better to use the smallest length screws that still joined the boards.

Just remember, the longer the screws the bigger chance of a split board, pre-drill your holes.

That's exactly why I thought it was best to use the shortest screws rather than the longest ones. This is where a good drill press comes into play.

As a rule of thumb you want about 1/3 of the screw length going into the piece that is in contact with the screw head.

The rule of thumb is to have 1/3 of the screw in the board to be fastened and 2/3" of the screw into the board being fastened to.

You can't really use a hypothetical question because the thickness of the wood to be joined changes the answer in varying degrees.

Another rule of thumb is to put your thumb on the back side of the work. If the screw goes into your thumb, it is too long.

Keep in mind that screws not only come in different lengths, but different thicknesses. I use mostly #6 and #8 for typical 3/4" wood but if you are working with 2 x 4's and the like #10 or #12 may be better. Pre drilling a pilot hole helps as does a countersink. You can get bits that do both in one operation.

Buy good screws. Buy from McFeelys, Lee Valley and the like, not Home Depot. I also like the square drive screws too.

Hmm, didn't know that.

My apologies.

Well in this case I'm installing a 1/2" stiffener board to the backside of a

Sometimes the longest possible screw will give the best holding power. You can take a 1" screw and grind off about 1/16" so it won't blow through. I still use a regular screwdriver in cases where I need the greatest possible control, and this sounds like one of them.

For that scenario, I'd probably use a #8 1-1/4 or 1-3/8 through the stiffener into the plank. Flat head countersunk if I needed the head to be flush.

Tom Veatch Wichita, KS USA

See Chapter 7.