All Replies on Screw Sizes Types, et cetera

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View Phlogis's profile

Screw Sizes Types, et cetera

by Phlogis
posted 02-05-2013 08:53 AM

17 replies so far

View DIYaholic's profile


19623 posts in 2700 days

#1 posted 02-05-2013 01:25 PM

From what I remember reading, as far as thread pitch (fine Vs. coarse) goes, hardwoods should recieve fine threads & softwoods should recieve coarse threads. Sorry, I can’t offer or recommend any screw gauge advice.

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View kizerpea's profile


774 posts in 2392 days

#2 posted 02-05-2013 01:26 PM

Wrong ….fine thread for hard wood …coarse thread for soft wood…coarse will ring off in hard wood…or find out the hard way…or buy a kreg jig…lots of us have them..


View poopiekat's profile


4356 posts in 3759 days

#3 posted 02-05-2013 01:48 PM

I’m not aware of pitch choices in wood screws. Drywall screws, maybe, but not wood screws.

-- Einstein: "The intuitive mind is a sacred gift, and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift." I'm Poopiekat!!

View JoeinGa's profile


7736 posts in 2031 days

#4 posted 02-05-2013 01:58 PM

I Googled and found a simple cart for pilot hole sizes. Printed one out and hung it near my workbench. I refered to it fairly often till I started remembering which size drill bit for which size screw.

Here’s a couple to choose from


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View DIYaholic's profile


19623 posts in 2700 days

#5 posted 02-05-2013 02:11 PM

Good point. I was refering to pocket hole screws.
From the posted chart links (refering to standard wood screws), Hardwoods get a larger diameter pilot hole than those for softwoods.

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View Ted's profile


2873 posts in 2236 days

#6 posted 02-05-2013 02:24 PM

I generally use what screws I have on hand at the time, or whatever the store stocks. Then I use the appropriate size drill bits to make pilot holes as needed. For wood screws, I would drill an initial pilot hole for the upper shank portion of the screw, then drill deeper with a smaller diameter bit for the threaded portion. With hardwoods I would make the threaded portion of the pilot hole just a little smaller than the diameter of the threads, or just enough to give them some bite. For softwoods I make the threaded portion smaller to give the screw a little more bite.

For all of this, I generally don’t measure anything.. just hold drill bit against the screw and eye it for the right size. I often put just a touch of wax on the screw for hardwoods, to help them drive in easier.

Welcome to LJ’s

-- You can collect dust or you can make dust. I choose to make it.

View JesseTutt's profile


854 posts in 2135 days

#7 posted 02-05-2013 02:47 PM

I don’t have a McFeelys catalog handy but they have a lot of useful information in it. I know they have a drill size chart for different types of screws and discuss different screw (metal) made from. I don’t recall if they have a chart for screw diameter use.

For structural joints I tend to use the largest screw I can. For non-structural whatever size I have a lot of.

-- Jesse, Saint Louis, Missouri

View Bill White's profile

Bill White

4948 posts in 3985 days

#8 posted 02-05-2013 03:37 PM

+1 on gettin’ a McFeely’s catalog. More than you’ll ever want to know, and they have quality products.


View Cosmicsniper's profile


2202 posts in 3183 days

#9 posted 02-05-2013 03:47 PM

When using the pocket hole screws, I always use coarse threads on hardwood simply because I always strip out the fine thread ones. Then again, I’ll often break off the coarse ones by over torquing. Either way, I’m too reckless with pocket hole screws…because i’m an impatient idiot. You likely won’t over -torque your screws like I do, so it’s probably not an issue and you can use fine threaded screws in hardwood with good effect.

-- jay,

View waho6o9's profile


8207 posts in 2601 days

#10 posted 02-05-2013 04:31 PM

GRKs are an option and available at Home Depot as well.

Welcome to LJ’s Austin and enjoy your journey, it’s going to
be a good one!

View MrRon's profile


4794 posts in 3268 days

#11 posted 02-05-2013 08:14 PM

A lot depends on your application. if it is a structural joint where failure is not an option, you need to use glue. Screws will then act as “clamps” until the glue has set. Glue joints can fail if moisture is allowed to penetrate the joint. Screws can be the secondary joint strength and a larger screw may be needed. Not knowing what the sizes of wood you are joining together, it is difficult to tell you what size of screw to use. There is only one screw pitch per size of screw used for either soft or hard wood; no fine or coarse pitch. The pilot hole is what will vary depending on the hardness of the wood. Go to this link, chapter 7 will tell you everything you need to know about screws or anything else for that matter.​Wood​Handbook.html

View Phlogis's profile


6 posts in 1962 days

#12 posted 02-05-2013 11:53 PM

Thank you all for your great responses!! It’s much appreciated. I’m now positive of how I’m going to implement my fine threaded screws using the pilot hole charts based on my screw type.

But honestly I’m still not sure if I’m to use, #6, #8 or #10 sized – and why

For clarification purposes, I’m attaching a 21 inch red oak 2×4 flat against some 5/4 red oak with glue between the joint. And it needs to be very sturdy, as I’d like the quality of this piece to be high and lasting.

Thank you for the warm welcome.

-- Newbie

View huff's profile


2828 posts in 3310 days

#13 posted 02-06-2013 12:59 AM

A #8×2 1/2” fine thread screw would give you all the strength you need; as long as you don’t twist it off in the red oak. If you pr-drill a pilot hole, you should not have a problem.

A little trick you can do when running long screws into hardwood is to put a little soap on the threads of the screw for lubrication. I keep an old bar of hand soap in the shop for that purpose.

-- John @

View oldnovice's profile


6898 posts in 3392 days

#14 posted 02-07-2013 01:40 AM

Without any detail about the loads on the pieces it is difficult to to suggest what size of screw should be used. If the assembled pieces are just by themselves; not supporting anything else then the glue would suffice but if these pieces are part of something else and/or have a load on them then screws may be needed.

-- "I never met a board I didn't like!"

View MrRon's profile


4794 posts in 3268 days

#15 posted 02-07-2013 06:31 PM

“For clarification purposes, I’m attaching a 21 inch red oak 2×4 flat against some 5/4 red oak with glue between the joint. And it needs to be very sturdy, as I’d like the quality of this piece to be high and lasting.”

Are both sides exposed to view? Best to fasten through the 5/4 into the 2×4 and if exposed, counterbore and plug.

View runswithscissors's profile


2764 posts in 2050 days

#16 posted 02-08-2013 06:43 AM

True wood screws are becoming somewhat rare. They are the ones with a smooth shank below the head, and threads the rest of the way. The point of the smooth part is so the screw can pull the 2 parts together. With an all-thread screw, your pieces have to be in tight contact from the start. If, for example, you fasten 2 boards together with an all-thread, and start with a 1/8” gap between them, you cannot close up that gap with screws. The top piece hangs up on the threads, and can’t be pulled up tight no matter how hard you drive the screw. (Guess how I know this?)
Trouble is, not all boards that are going to be fastened to another board are going to be the same thickness as the length of the smooth shank, so sometimes they work fine, sometimes not.

As for McFeely screws, I haven’t used theirs, but I have used the so-called “combination” screws, for either phillips or square drive drivers. They’re supposed to be the best of both worlds. To me, they are the worst of both worlds. What does a phillips bit look like when the driver cams out? Like a combo screw, of course. And if you use square drive, well, the corners already have been conveniently rounded for you. I have had very poor luck using them, as you can probably surmise.

I’m with Ted when it comes to sizing screws: hold the screw up to your work (both pieces), and eyeball it. If it looks okay, it should be okay. By the way, I like the tapered pilot drills, such as Fuller’s. I have used them for years with good results. Some people think they don’t leave enough wood for the threads to bite into, but I have not had this problem, either in softwood or hard. They come with a combination countersink/counterbore which is handy, too.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View oldnovice's profile


6898 posts in 3392 days

#17 posted 02-08-2013 08:12 AM

I use Fastap whenever possible as IMO they are the best carpentry screws available today! These screws may not look as the traditional zinc wood screws as they are Black Oxide coated (that’s what my supplier carries) but they are also available Silver Unichrome.

I like them because the really pull two pieces together and I have yet to have one break or the head strip out!

I buy these at my local lumber yard and always buy a couple of boxes … just in case I may run out!

I only used McFeely’s screws once and was dissaponted in there strength, combo head, and the square drive head.

Take a close look at these and you will see why I like these screws!

-- "I never met a board I didn't like!"

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