# What size pilot hole for 3" deck screw?



## Goldglv

Please help out a beginner here. What size pilot hole would you use to drill a 3" deck screw through one 2x4 into another 2x4?

I have seen a miliion charts, all saying different things. I'm assuming 3" deck screws are #8 screws? Is this correct?

Going by that, most charts say to use a 3/32 or 7/64 drill bit. For me this is close to impossible, the screw will barely go in, sqeaking like crazy and constantly slipping.

I've used a 1/8 but that stills seems extremely difficult. A 5/32 worked much better but I'm worried that pilot hole is TOO big and it won't hold well.

I'm building a workbench, I bought these phillips II plus premium exterior 3" deck screws from Lowe's I'm trying to use. They have some type of "evercote" coating on the screws.

Thanks....


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## joed

None. Just drive it through.


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## user1007

Yup. They should pull themselves in. A SMALL pilot hole will certainly not hurt though. A large one will defeat the purpose.

Try rolling or drilling the screws into a little candle wax or parafin canning type wax first if they really scream. I usually keep an old candle from the table in my box. Do you have a screwdriver with enough torque? That lumber sounds less than kiln dried? Too cheap box store screws?


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## jlhaslip

I've seen them as #8's and #10's as well.


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## pyper

It sounds like you're driving them by hand -- is that the case? 3" deck screws can be driven with a screwdriver, but it's a workout.

You can drill a hole almost as large as the shank without altering the screw's ability to hold. You can spray the screws with wd-40 (if you're not painting) and they'll go in easier. Soap works too, if you don't have parafin.


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## user1007

pyper said:


> It sounds like you're driving them by hand -- is that the case? 3" deck screws can be driven with a screwdriver, but it's a workout.


:thumbup:My 55 year old wrists might or might not hold up to such repeated abuse, not that they are what they used to be drilling the things in either. 

WD40 is miracle stuff and could help getting your screws in. As mentioned it is a solvent. Candle wax, from years of experience, works as well as anything.

Isn't about time you suggested a candlelit dinner to your mate anyhow? She or he does not need to know your true motives. Don't buy the long 24" tapers though or he or she will demand to chat for hours. Just get the fast burning 12" ones. 

You "get lucky" and have a wax candle stub you need in your toolbox.


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## Goldglv

Using a Makita 18v lithium ion driver/drill to put these screws in. I will try wd40 or candlewax. So what size pilot hole should I use?


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## Bondo

> So what size pilot hole should I use?





> *You can drill a hole almost as large as the shank without altering the screw's ability to hold*.


Ayuh,... Did you read the answers posted..??


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## Goldglv

Bondo said:


> Ayuh,... Did you read the answers posted..??


Yes, I read the answers posted but no one mentioned what size exactly. Someone mentioned a small hole wouldn't hurt but I'm not sure how small, that's why I was asking. 

Also about the pilot hole being the diameter of the screw, yes, I understand that but there are a few drill bits that seem pretty close to the diameter so I wasn't sure which one to use.

Maybe it's not a cut and dry thing and that's fine but for a beginner like myself I wanted to be sure before I damaged my workpiece.


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## user1007

I still think you will find with some wax on your screws you are worrying about nothing. Use the drill smallest that you have if you are going to dirll a pilot hole. The concept of a pilot hole is to provide but a path for the screw. Smaller the better. 

The screw will find the path. If you are putting them in by hand, take frequent breaks. If with a power tool. Take a break too if they freeze on you. Get real screws from a fastener or hardware store if yours keep freezing up on you. Lowe's sells crap. Would not buy fasteners from them unless they were the last on Earth.


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## Goldglv

sdsester said:


> I still think you will find with some wax on your screws you are worrying about nothing. Use the drill smallest that you have if you are going to dirll a pilot hole. The concept of a pilot hole is to provide but a path for the screw. Smaller the better.
> 
> The screw will find the path. If you are putting them in by hand, take frequent breaks. If with a power tool. Take a break too if they freeze on you. Get real screws from a fastener or hardware store if yours keep freezing up on you. Lowe's sells crap. Would not buy fasteners from them unless they were the last on Earth.


sdsester,

Thank you for explaining. I will try the wax and let you know how it works out. Besides Lowes/Home Depot, what other hardware stores would you recommend getting screws from? I'm in Central NJ, there's an Ace hardware not too far away but I'm assuming that would be the same stuff.


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## brokenknee

The only place I ever drill pilot holes is close to the end to prevent the wood from splitting. It is not necessary to drill holes in the field of the wood.

The size I drill? One a little smaller than the screw, just hold the screw up to the bit and make sure it is not larger than the shank of the screw as already mentioned. Of course the drill bit I want is the one that is always missing. :laughing:


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## Daniel Holzman

Screws have two diameters that are normally discussed. The diameter of the threads is known as the thread diameter (big surprise there), and is the diameter you would measure if you put a micrometer to the screw and measured from thread to thread. The diameter of the shank (the unthreaded part of the screw) is known as the root diameter. If you have a thin micrometer you can measure that as well, else you can estimate it pretty closely by putting up a nail of known diameter against the screw and checking to see if the root diameter of the screw is the same as the diameter of the nail (by eye).

You want to drill a pilot hole that is the root diameter of the screw. In the case of tapered screws, you would drill a pilot hole that is approximately the average root diameter.

On some screws, the box will actually list the thread diameter and root diameter, but this is unusual. For certain types of screws (specifically concrete screws), the box will often contain a drill bit of the correct diameter for installation of the screws. If the pilot is too large, you lose pull out strength, if too small, it is hard to install the screw, and you risk breaking the screw off during installation.

In addition to the suggestions previously offered, since you are using an electric driver on a relatively long screw, you can reverse the screw direction about halfway through the install, then finish the install, this often works to reduce the chance of breaking the screw off.


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## Kevin M.

Try these. They are self drilling and designed to attach 2X material. 

http://www.mcfeelys.com/product/0827-FPT/8-x-2-78-ProMax-NoCoRode-PLUS-Plated-Screws


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## YesMaam27577

<<" I'm in Central NJ, there's an Ace hardware not too far away but I'm assuming that would be the same stuff.">>

Look in the phone book to see if there is a Fastenahl store nearby. Those folks have every type of fastener known to man, and all are generally high quality.

As for those holes -- just about any pilot hole is just about as good as any other, so long as the screw head doesn't fall in. And note that your drill-driver is strong enough to drive those screws without any pilot holes -- though your wrists might get a bit tired.


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## pyper

Goldglv said:


> Using a Makita 18v lithium ion driver/drill to put these screws in. I will try wd40 or candlewax. So what size pilot hole should I use?



What kind of wood are you using that can stall out an 18v Makita?

I had some old southern yellow pine studs that I couldn't get #10 four-inch screws into without pilot holes. IIRC, pilot holes for any mechanical fastener in wood can be 90% of the diameter of the fastener without compromising the strength -- just pick a bit by eyeball. Or you can buy bits sized for screws and use the bit for the size of the screw. #8 or #10 for 3-inch (depending on if they're #8 or #10 screws). 

You should use decking screws, not drywall screws.

You can also drill a full sized pilot through the top piece. I might do that if I was working in oak, for instance, especially near the end of a small piece of wood.

I get my screws at Lowes and Home Depot. I don't know if there are better screws available, or what would make them better. The ones I get go in and hold the wood together, and that's all I need them to do. Occasionally (a few times in a five-pound box) I break them off as they're going in. Usually it's because I'm running them into a knot, or that old southern yellow.


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## skymaster

drill a hole the same size as the screw in the first 2x ( called clearance hole ) then drive it right home. usually a 3/16 clearance is a good size


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