Selecting screw/nail sizes

I'm building an outdoor planter box(about 6.25"x6.25"x13 feet)that will attach to the side of my house. The pine lumber was nominally 1x8, ripped to 6.25" and with a true thickness of 3/4". How should I select a screw or nail to attach the 7.75 x 6.25" end cap? I only have 3/4" to stick the fastener into, which means that there is only 3/8" of wood on either side of the fastener.
The concern is splitting. Number 7 screws, 1.5" cause splitting, even if I predrill; #6 screws can work if I predrill everything and am careful to make the pilot holes perfectly parallel to the face of the lumber. With about 40 fasteners required, this is tedious.
The original box was held together with 1.5" staples. I don't own a stapler, but renting one is a possibility. Any suggestions for nail sizes?
Thanks,
Ray
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wrote:

I would use wood glue and 4d finish nails. You can pre-drill the holes, drive the nail and the sink it with a nail set.

-- Oren
"I don't have anything against work. I just figure, why deprive somebody who really loves it."
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The screws aren't flat head screws, are they? If so the taper under the visible head surface (sorry, I'm not up on screw terminology) will tend to cause the wood to split as it's driven deeper. If you use pan head screws you won't have that problem.
R
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RicodJour wrote:

Yes, the screws I used for testing have flat heads, somewhat like sheet rock screws. I could countersink the holes to prevent this problem. Wouldn't I also have to countersink for pan head screws to get them flush with the lumber?
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A countersink is tapered, such as used for drywall and flat head screws, and it creates a wedging action as the screw is driven home. That is what's causing the wood to split. A counterbore for a pan head screw would have a flat bottom. That provides a clamping action and won't wedge the grain apart. http://en.wikipedia.org/wiki/Countersink http://en.wikipedia.org/wiki/Counterbore
You could also use stainless steel finish washers and eliminate the counterbore. The flat head screw would still sit proud of the surface, but it might satisfy your aesthetic requirements. http://www.jamestowndistributors.com/userportal/show_product.do?pid 10&familyName=Stainless+Steel+Finish+Washers
R
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RicodJour wrote:

Thanks for the excellent points. I had been thinking that if I don't overtighten, a countersink would be okay. But with regard to the effort involved, countersinking or boring would be equal.
At this time, I'm thinking of using a #4 pan head screw, 1.5 or 1-5/8 long, with a pilot hole the complete length of the screw and a counterbore. Sound okay?

http://www.jamestowndistributors.com/userportal/show_product.do?pid 10&familyName=Stainless+Steel+Finish+Washers
I prefer that the screw head be flush or below the surface.
Thanks,
Ray
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Stick with #6's .....4's are too small. I would suggest a very coarse thread like a drywall screw but not drywall screws
like this
www.mcmaster.com part number 92325A309 Sharp Point Thrd-Form Screw for Plastic 410 SS, Pan Head Phillips, 6-13 Thread, 2" Length In stock at $8.34 per Pack This product is sold in Packs of 50
or
93406A158 Large Dia (Truss) Head Phil Sheet Metal Screw 18-8 SS, No 6 Size, 1-1/2" Length In stock at $10.63 per Pack This product is sold in Packs of 100
but it's only 1.5" long
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RIco's comment of the flat heads tending the split the wood is "spot on"
Even if you countersink for the head the splitting potential is still there because of the shape of the underside of the head....its like a wedge.
The underside of a pan head is flat so even if you counterbore (that's the correct term for a straight sided hole that the head goes into) there is no wedging action to cause the split .
My suggestion is long (2") #6's with 3/32 pilot hole, use a 6" long drill bit (the long length will help you with your hole alignment)
Use some scrap material to practice.....pine is pretty soft, you might have to adjust the pilot drill size up or down.
Bigger pilot, less bite, screw might strip out Smaller pilot, more bite, wood might split
The hole thru the end caps should be screw diameter not pilot size.
oops! I should have read furhter before posting redundant info
cheers Bob
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Ray K wrote:

I'd use a 6d (I'd prefer a 7, but they're getting very hard to find any more :( ) finish nail or if you don't mind the head even a 8d _box_ nail would do. A box nail, if you're not familiar as a smaller shank than a "common" of the same penny size for, as the name suggests, the precise reason.
Although it won't make any long term difference in strength because of the end grain, I'd use Type III glue or this is a place where even urethane glues have a place for the waterproof nature as a moisture seal to prevent mostly water wicking into the end grain.
--
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Can't the glued bond be stronger than the actual wood?
I may need my myth busted :( -- Oren
"I don't have anything against work. I just figure, why deprive somebody who really loves it."
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Oren wrote:

Not on end grain. Glue joints rely on long grain to long grain orientation for their strength. (*) End grain fibers can't form the bond. It may hold for a little while as a mechanical bond, but even new it won't have much strength and will certainly fail in the long run. As noted, I use the glue for such applications as a moisture preventative, not as a bonding agent. Pre-painting the end grain accomplishes much the same objective but the glue is usually a little more convenient at the time one is in the "putting it together" phase and wet paint is just a lot more messy to use it at that time instead of glue. Dries more quickly, too, in general, although the urethanes are pretty slow...
(*) Doesn't have to be parallel, but does have to be long grain. That is, a cross-lap joint is fine whether the boards are joined end-ways or at 90-degrees. Or the tenon cheek against the mortise side. But, similarly to here, the tenon rail sides (top and bottom) even though snug fitting, the glue surface there to the end grain in the mortise don't contribute except for resisting racking forces and that only mechanically.
--
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I can appreciate that! -- Oren
"I don't have anything against work. I just figure, why deprive somebody who really loves it."
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I would put cleats in the corners and then use wood screws into the cleats. This after gluing the all the involved wood surfaces. It is important to consider the weight when this box is filled with soil and water is added either by rain or irrigation. This is also a consideration when attaching to the house
Charlie
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Ray K wrote:

In reviewing some of the suggestions for using glue, I should have pointed out that all surfaces have been primed with an oil-based primer (Zinzer) to resist water entry into the end grain. (After assembling the box, I may give the interior surfaces a second coat of the same primer, followed by a latex finish coat.) I suppose the primer interferes with the holding power of glue. I never considered glue as an option.
Also, I don't plan to fill the box with soil, but will use it merely to hold container plants, so the weight of the box is not an issue and attaching it securely to the wall is easy.
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wrote:

Don't say *even* if I predrill. You should always predrill if there is the slightest chance of splitting, as there almost always is. Even for finishing nails. With screws the hole can as big as the screw shank, not counting the threads. With nails it has to be a little smaller than a nail.

I can't envision the work, but even if you need to drill all these holes, you may be able to speed things up. Make probably 4 attachments so the thing stays together. Then in the top piece of each connection drill the hole for the shank of the screw or nail the size of what is closest to the head. AIUI you can make that hole so big you can push the screw in with your finger, but of course not so big that the head of the finishing nail will go through. Drill all the holes of that size. Then change bits to a smaller one that will. Hold the top piece in place, drill a hole, and screw or nail the pieces together. Same thing in a second place, maybe caddy-corner to the first one, and screw or nail the the pieces together. Maybe go on to another piece then, or finish the one you are working on, but at some point, you'll be able to just drill, drill, drill, drill, then come back and nail, nail, nail, nail, (or screw etc.)

IIUC, they used a stapler because it was quick and easy, not because it was good. Note that it is falling apart now. That's what often happens with staples. Not that there isn't a place for them in quality work. I just can't remember where that place is.
(But I forget a lot. Upholstery maybe; temporary attachments; a portion of installing some convertible tops, in the tack strip above the rear window, for cars that attach there. My first top said to use carpet tacks iirc, perhaps because consumer staple guns were rare in 1970. The pros use a staple gun; and some others.) BTW, a standard electric staple gun is only a dollar or two more than a manual staple gun these days. Quite amazing. I forget the price, but even a cheap guy like me thought it was cheap. I think I bought it to attach cloth to wood in a situation where I was working alone, and couldn't hold the cloth in place while I hammered in tacks, because that would all take three hands. With the electric stapler, 2 hands were plenty. I felt like a dynamo. Just don't point it at anyone.)

I don't know any sizes by heart.

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mm wrote:

mm,
Thanks for the excellent "production line" tips for speeding things.
The box was installed when the house was built in 1968. So I can't really complain that the staples didn't hold up well over the decades. When I bought the house in 2000, some of the pieces had separated, but just as important, much of the inside wood was rotted. I'm embarrassed that it's taken me seven year to replace it, but now that I'm about to paint the whole house, might as well do everything right.
Ray
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wrote:

Nor can I complain either. :)

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Ray K wrote:

This has been a great thread and I learned a lot about screw geometry. Thanks to all who have contributed.
I have one question, directed both to the OP and the other responders.
AIUI, this is to be an outdoor planter box.
Why pine?
Why not a wood more resistant to the kinds of damage that dirt and water in a planter box will do to wood?
Seems to me the labor part of building this (as evidenced by the OP's iitial question) is the hardest part. In my experience, with pine, you are going t d this agan in 5 - 7 years. Why not use cedar or cypress or even redwood? Or a composite? Or a really tugh South American wood? Sure, its more expensive for materials than pine, but ou don't have to re do it.
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jJim McLaughlin wrote:

Pine, mainly because it's easy to get in the length (13+ feet) that I need. Initial expense was not a factor.
The box I'm replacing was almost 40 years old and made of what appears to be pine; considering that the cheap builder used pressed paper for the fascia and soffits, I can't imagine him using anything but the cheapest for the planter box. Had the inside been maintained better, I'm sure it would have held up much longer despite being pine. The separation at the corners where the staples pulled out could have been easily fixed.
To improve weathering capability, I'm double priming all surfaces (and edges and ends)with an oil-based primer before assembly. I'll apply a latex finish coat. I don't plan to put soil in the box; it will be used mainly to hold potted plants. I still have to figure out how to place drainage holes for rain.
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jJim McLaughlin wrote: ...

Because pine is a perfectly reasonable (and inexpensive, relatively) choice for the purpose. Paint it and it will last quite a long time as OP noted his original did.
--
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