Screws versus Nails

[MarkW]

I need to attach a wood rail to a post for a fence. Someone suggested using a Kreg pocket hole jig that uses screws. Do screws have more or less shear strength than nails? Does anyone recommend using screws over nails or vice-versa?

 

[Trussdoc]

Shear strength will vary with the diameter of the fastener more than with the strength of the metal; the shear joint will usually fail when the wood under the fastener compresses.

What a screw will provide is withdrawal resistance for a longer time if the fence is exposed to the weather. If you want to make the fence more than decorative, I would recommend screws, rather than a nail. I can tell from personal experience that a worn 6D nail in a fence is weaker in withdrawal than a Lab retreiver puppy...

 

[MarkW]

Do I know you Trussdoc? How did you know that I am making the fence b/c of our new Lab Retriever puppy???

 

[Trussdoc]

Just coincidence....I was just amazed how much damage an excited dog can do, and how weak nails really are in withdrawal.