DECK SCREW SIZES?

[justme]

What sizes of deck screws are there?

What size do I need to attach doubled 2x4 legs to the top perimeter of a

4x8' work table using 2x4s as the perimeter?

Thanks

j/b

[David Nebenzahl]

On 5/21/2009 11:37 AM justme spake thus:

Doubled how? On top of each other (i.e., 4x4) or next to each other?

We need more information.

Right off the top of my head, I wouldn't use deck screws anyhow. Think carriage bolts.

[Chris Friesen]

I used #10 3" screws when I built something similar. You could glue it as well, in which case the screws would be there mainly to clamp it until the glue dried.

Chris

[Leon]

Typically the screw should be 1/3 for the thickness of the material to be attached, 2/3 for the material being attached to. for a 2x4 the thickness is 1.5" your screw should 4.5".

If you countersink you can reduce the length by equal amounts. Counter sink

3/4" the screw could be 2.25"

[fftt]

If I'm understanding your design correctly......I would suggest using

2x8's with a taper cut on them.

or a 4x4 with two faces tapered

For a sturdy attachment of the legs to the 2x4 table perimeter, a 2x8 will allow for a much larger over lap than the 3.5" square between a

2x4 leg & the perimeter.

The tapered 4x4 can be screwed into through the perimeter 2x4's.

A horizontal plywood gusset / corner stiffener will go a long way to strengthening the leg / table connection.

cheers Bob

[fftt]

But to answer your question...I'd use #10 x 3 or 3 1/2" depending on the final design.

If you use the 4x4 legs I'd suggest using 4" & 3" such that the screws don't interfere.

cheers Bob

[justme]

Thanks, guys.

I think that I will use carriage or through-bolts.

j/b

[-MIKE-]

FWIW, if you design the legs like a door/window's header support, you won't have to worry about the fasteners bearing the load.

You may know this already, but... A header's framing uses a king and jack stud. The jack stud sits under the header and holds all its weight. (I always think of it like a car jack.) The king stud continues up the side of the header to the top of the wall.

In your situation-- legs consisting of two sistered 2x4's-- one could act as a jack stud, sitting directly under your 2x4 "ribbon" that goes around the perimeter, supporting all the weight; and the other could continue up the side of the ribbon to the table top.

[Lew Hodgett]

Personally, I avoid carriage bolts like they were the plague.

Much prefer hex head machine bolts with a fender washer under the head and nut.

Lew

[notbob]

That's what I plan on using for the upright 2x4s (handrail) I'm attaching to the step stingers on our deck. Zinc 3/8" thru bolts with fender washers. I want some serious compression on that wood besides the actual fastener shear strength. I'm a machanical type, so any advice is welcome in this new wood world.

nb

[David Nebenzahl]

On 5/22/2009 11:02 AM Lew Hodgett spake thus:

Just curious, why? Esthetic reasons?

I actually prefer carriage bolts for this type of fastening. The head bits into the wood, locking the bolt (I usually recess the head with a shallow counterbore). And of course on the other end where the nut goes, it doesn't make any difference.

[-MIKE-]

On treated lumber, it's usually self-recessing. :-)

[Lew Hodgett]

Do yourself a favor.

Spend the money to go galvanized.

Five (5) years from now, you will be glad you did.

Lew

[Lew Hodgett]

Try to retighten a carriage bolt after a few years.

When the carriage bolt head starts to spin before the bolt is tight, you'll know why.

Lew

[David Nebenzahl]

On 5/22/2009 1:09 PM Lew Hodgett spake thus:

Funny, I've *never* had that problem.

Mind you, I'm talking about stuff that sits indoors. Come to think of it, I've never even had that problem with the few carriage bolts I've used outdoors.

[notbob]

Oops.... that's what I meant.

BTW, galvanizing is a zinc coating process.

nb

[Lew Hodgett]

Sounds like a rookie to me.

A few more years and you will.

Carriage (coach) bolts are like motorcycle riders, there are two kinds.

Those that have slipped and those that will.

Lew