Description of nail lengths in the U.S.
pmikwheaten
| Posted in General Discussion on
Have been subscribing to Fine Homebuilding since the first issue and have been meaning to ask this question for years.
As a Canadian it always surprises me to see nails in the U.S. described as 10p 12p, etc. instead of (what seems to me) a more logical description…namely 2″ 3″ 3 1/2″, etc….as screw lengths are described. This seems like an unnecessary anachronism going back to English nomenclature (pre 1776?).
Any interesting comments?
Replies
nails in the U.S. described as 10p 12p, etc.
Actually, the nails are designated as 8d, 16d, etc. ("d" not "p").
I have no idea why "d" stands for "penny". ;)
But we use a lot of antique language in carpentry. Who else knows terms like rabbet, dado, mortise, muntin, stile, or plinth?
Oh, it's British all right. Before the Brits changed to decvimal currency, pennies were denoted as d., and shillings were s. Hence a sum of four shillings and eightpence was written as 4s. 2d., or shortened to 4/2. Original source of the d. is from the Latin denarius.
And I agree, why not just call the thing a 2 inch nail?
Lignum est bonum.
Original source of the d. is from the Latin denarius.
Thanks for the explanation -- I like trivia stuff like that. But I'm a bit confused. Doesn't denarius translate to "containing ten"? How does this apply to a penny?
And do you happen to know the origin of designating the nails as 16-penny, etc.? I've assumed it had something to do with the price structure, but I could be entirely wrong.
Just answered my own questions. From Wikipedia:
In the US, the length of a nail is designated by its penny size. It is commonly believed that the origin of the term "penny" in relation to nail size is based on the old custom in England of selling nails by the hundred. A hundred nails that sold for six pence were "six penny" nails. The larger the nail, the more a hundred nails would cost. Thus the larger nails have a larger number for its penny size. This classification system was still used in England in the 18th century, but is obsolete there.
The penny size is written with a number and the abbreviation d for penny (e.g. - 10d). D is an abbreviation for denarius, a Roman coin similar to a penny.
So I guess a penny just resembled a denarius in size or something.
Ragnar, like many things Wiki, I think they are wrong.
It was a measure of the weight of steel in the nail. A sixteen penny nail was equivalent in weight to 16 pennies. You couldn't always trust a vendors weights on the counter balance scale, but coinage was standardized and common.
Well... you might be right, I don't know.
But here's some corroborating evidence for the price per 100 version:
For example, four penny nails were those of which a hundred were purchased for 4d. (The 'd' stands for pence in the days when sterling was denominated in pounds, shillings and pence - £ s d).
The account records of the Church of St Mary-at-Hill show -
'ffor a c of v peny nayle vd'
The 'c' is the Roman numeral for 'hundred' and 'v' is the Roman numeral for 'five'.
From: http://www.glasgowsteelnail.com/nailnames.htm
because they are 1-7/8" ....
.
."First thing I would do is shoot the carpenter"
You have touched on one of my pet peeves. Why the largest industrialized country in the world is still using antique systems of weights and measures completely baffles me. And as an American, it actually embarrasses me.
I still sometimes look at a tape measure and say to my myself "ok, it's 1/32 of an inch less than 9 feet, 6 and 3/4 inches". That's 3 distinct units of measure; feet, inches and binary fractional inches. We must be out of our minds!
And then theres weights and volumes which are both measured in ounces. So we can have a cup of water (8 ounces as measured in volume) and it actually weighs 8 ounces, but we can't have a 2 cup hammer.
And how many yards are in a mile?
I could go on, but for now, I'll just say that we ought to join the rest of the world and use one logical, easy to use systems of weights and measures.
-Don
There 1760 yds. in a mile.
You think you have it bad? Up here in the Great White North, we have to use both Imperial AND metric. In the 70's, we switched to metric, but the U.S. didn't. So, being that the U.S. is our largest trading partner, we had to adopt both.
I routinely get drawings that are metric, but the Millwork co. supplies drawings in Imperial, or vice versa.
I can cut a roof with a metric rafter square, the hip point is 352.
And try to figure if gas is cheaper in the States! Convert litres to gal., (imp. or U.S.) convert currencie, U.S. to Can.
10d nails? I don't know, gimme a handful and I'll tell ya if their O.K.
<end rant>
Karpcandotoo
There 1760 yds. in a mile.
You cheated. You already knew that there are 36 inches in a yard and 63,360 inches in a mile :-). Actually, I can remember that there are 5,280 ft/mile but I'm surprised by how many people don't know this.
But anybody can remember that there are 1,000 meters in a kilometer ("kilo" means thousand).
I can remember that there are 5,280 ft/mile
Except for those of us who also remember miles as being 6075 feet or 2025yards (even if a nautical mile is really 6076± feet; or 1852m exact).
Or that it was Lizzie I, who "evened" the Roman 5000 millus paceus "mile" to 5280 feet so as to be an even number of rods/furlongs, since those already had legal standing at the time.
Which is like tons, "long" tons jsut happen to be a even number of hundredweight and CWT is an even number of Stones (unknighted, non-rolling <g>).Occupational hazard of my occupation not being around (sorry Bubba)
I have never heard of 6075 feet in a mile. I just picked up a tech book written in 1908 and it was 5280 feet back then.
How old are you....................................really:)
roger
5280' = statute mile (land mile); 1 mile per hour = travelling 5280 feet in 1 hour.
6076.1' = nautical mile (water mile); 1 knot =travelling 6076.1 feet in 1 hour
This is why the phrase "knots per hour" is redundant and incorrect. The phrase " knots per hour" actually means - 1 nautical mile per hour per hour.
Vessel speeds and wind speeds are properly quoted in knots since they relate directly to nautical charts which are drawn in nautical miles for scale.
Reference Source: Chapman's Basic Seamanship and Small Boat Handling.
Jim
Never underestimate the value of a sharp pencil or good light.
Vessel speeds and wind speeds are properly quoted in knots since they relate directly to nautical charts which are drawn in nautical miles for scale
Don't forget that a nautical mile is also (or used to be) 1 minute of arc of latitude (or "great circle" arc). Makes the nautical Quartermaster's job a tad easier, dividers can be set to the one scale and be done with it.
1852m at least is a neat, if not round, sort of number. Better than the old "sea mile" of 1000 fathoms, or 6000 feet (or 200 cables), which, while both round, and neat, was not terribly useful.Occupational hazard of my occupation not being around (sorry Bubba)
Right you are. I figured that would further confuse Roger.
I hold a USCG Small Passenger Vessel Master's license, 100 tons, 100 miles and taught other people how to pass the tests for several years.
Jim
Never underestimate the value of a sharp pencil or good light.
and taught other people how to pass the tests for several years
Cool. I just used to organize how to let 20 y/o have a shot at drowning Marines on beaches in batches <g>
(And grew up confused when other people's houses did not have well-thumbed copies of Knight's, or Bluejacket's or Bowditch about, or the like . . . )Occupational hazard of my occupation not being around (sorry Bubba)
Nah you wouldn't. I may look like a cabbage but I don't think like one. I knew what a nautical mile was (not the actual footage but I knew it was bigger due to the arc of the world) but I thought he was talking about land miles. Of course if I had know the footage of the nauticle mile I would have twigged it.
Wasn't knots had to due with knots on a rope that they used to throw over the side and then walk the length of the ship or something. Work with me on this, I'm winging it.
Just something for you old salty dogs, Did you know that the US and Canada figure their tide heights differently. I just read about it. Of course we do it the right way:)
roger
Edited 6/14/2007 6:13 pm ET by roger g
"Knots" originates from what was known as a "chip log" - not misspelled.
A chip log was a piece of wood ( a chip from a log ) which was weighted to float vertically and provide great resistance in the water. The log chip was attached to a spool of line. KNOTS were tied in the line at intervals of 47'3". A small hour glass timer completed the set - along the lines of an egg timer in size. (Actually the line was marked with siezings so they did not hang up on the rail and destroy accuracy - seizing = knot.)
In practice the log chip was thrown over the stern of the ship, the timer was inverted and one counted the knots which passed over the rail while the sand ran through the timer. The count = ship speed through the water in knots. Low tech, clever and essentially bulletproof.
I was unaware that Canada and the US figure tide heights differently. US nautical charts are marked with the water depths (soundings) at mean low water ("datum" hereafter). US tide tables show a "tidal correction" in feet which is applied (either + or -) to the charted datum at a particular location.
In order to accurately predict water depth one must know the location (tidal station), date and time. Say Chesapeake Bay Entrance, charted depth = 42', tidal correction at high tide on June 16, 2007, 1453, is +4.6' (from tide table). The following calculation is required 42' + 4.6' = 46.6' predicted depth at this time.
As in all things involving natural elements, there are nebulous factors in play - such as - if the wind has been northerly for the last 3 days the tide may not be that high due to the water being blown out of the bay. This happens fairly often in this location and one needs to confirm with other instruments - a lead line in the old days - depth sounder in modern times.
Lead line = line attached to a lead weight, line marked in fathoms (6') - toss it over the rail, walk back along the rail until it hits bottom and read the mark at the surface. Low tech and bulletproof. Spawned the pen name of Samuel Clemmens - Mark Twain - 2 fathoms, 12' - the amount of water needed for a Mississippi River stern wheel steam boat to pass safely.
When the draft of your vessel exceeds the depth of the water, you are most assuredly aground.
How do the Canadians figure their tide heights?
Jim
Never underestimate the value of a sharp pencil or good light.
Edited to correct my math - oops! we are aground with a few hundred thousand barrels of oil aboard.
Edited 6/14/2007 9:22 pm ET by JTC1
Well, the way I remember it was that we start at what is normal low tide and so everything above that is a plus and on very few days of the year like RIGHT NOW we have the lowest tide of the year and that is a minus measurement and seems like the only time there is a minus number. I just looked and the minus appears only on 3 days for the month.Whereas you guys start at possibly a median figure and go up and down in your measurements. So I'm guessing you would have a lot of negative numbers.
I live about 100yards from the ocean and there are tide tables in the local newspaper which I can scan but am unable to paste on this site but can to a private email address.
Another interesting fact is that a billion in the US is different than a billion in Europe. Not sure about England.
roger
Yes there are a large amount of negative numbers, however, the negative numbers tend to be rather small, generally less than 2' in my area, whereas the positive numbers tend to be larger - in the 3 - 4' range.
I suspect one system starts with the mean and the other with the median. US charts are drawn with "mean low water" as the base for soundings.
>Another interesting fact is that a billion in the US is different than a billion in Europe. Not sure about England.<
I thought mathmatics were constant the world over. In the US a billion is one thousand million. 1000 x 1000 = million, 1000 x 1,000,0000 = billion, or 1000 x 1000 x 1000 = 1,000,000,000 = 1 billion.
What is the European version? Maybe this explains some of the difficulties at various trade talks around the world.
Jim
Never underestimate the value of a sharp pencil or good light.
UK terminology is that a billion is a million million; a thousand million is a milliard. I hear from some of my British correspondents that the US usage is being gradually adopted. Also, the practice in the EU is that a comma is used for the decimal point instead of a period.
Phew! I'm glad you answered that one for JTC1 because I didn't know the answer but now that I see it, it makes sense.
I always wondered about the way they use those comma's instead of periods. I think sometimes they even have just one number after a comma where we would/should have always 2,even if one is a zero.
Another regional thing, in England and Canada we say for Z zed where you guys say zeeee.or for a semi-trailer we say semeeeee and you .sem(eye).
Disputantum means I'm guessing....debate ?
roger
"Disputantum means I'm guessing....debate ?"
Close enough. From a Latin proverb: De gustibus non disputantum est. "Matters of taste cannot be disputed."
I think sometimes they even have just one number after a comma where we would/should have always 2,even if one is a zero.
Unless you're dealing with currencies, there's no need to have a certain amount of numbers to the right of the decimal/comma. This goes back to something called "significant figures" but I won't bore you with an explanation.
Europeans will often denote a price of a product with something like this: 2,- meaning that the product is exactly two Euros (or whatever currency), as opposed to writing it like this: 2.00.
Also, have you ever seen the way they make a number "1" when writing by hand? It looks like some sort of cross between a "7" and a greek "lambda". The little "flag" at the top of the "1" starts way down at the base. It's pretty confusing until you get used to seeing it. They typically put a line through a "7", so that helps to differentiate the two.
Edited 6/15/2007 3:04 pm ET by Ragnar17
1,000,000,000,000 = UK billion. Wow, bit of a difference there!
Jim
Never underestimate the value of a sharp pencil or good light.
I know, I know. Everytime I check my finances I find it confusing " is it 1000x million or is it a million x million."?
roger
a thousand million is a milliard
And 10,000 million is a "billiard", IIRC (but not "billard," as that's "snooker" <g>)Occupational hazard of my occupation not being around (sorry Bubba)
I've never heard "billiard" in that sense before, so I resorted to looking it up: Names of Large Numbers. Looks like I was a little off in my info.
heard "billiard" in that sense before, so I resorted to
Ah, but it's a great obsfucation word for logistical operations reports. After all, 13 twenty-ton CONEX's of ammunition does not sound like that much. Report that as 130 milliard rounds of rifle ammunition, and it's more like endless bucket-fulls instead of a baker's dozen truck trips (which the 15 mile 15kt "commute' by LCU(L) resembles not in the slightest <weary sigh> . . . )
looking it up: Names of Large Numbers. Looks like I was a little off in my info.
Off? "Skewe's Number" is definitely "out there," if not completely and utterly "off" <g>Occupational hazard of my occupation not being around (sorry Bubba)
I read in John McPhee's book "The Curve of Binding Energy" that the largest number it makes any real sense to talk about is 10 to the 123rd power.
That is the volume of the universe measured in cubic fermis. A fermi is a unit of measurement which represents the radius of the nucleus of some small atom like hydrogen, I think.
If you chase the wiki article over to the Skewe's number section, there's a link ot Avogado's constant, which is a value that lets a person scale the elements on the periodic table.
Avogado also either described mathematical naming, or enscribed a naming system that went to some scary numbers in incremental powers of 12. So, from a plebian 10**12 to 10**24 to 10**36 and hence on up to 10**144 and further without traking up notation as Skewes did, as powers of orders, 10**12**(10**12) and such like. Mind boggling.
Along with long-hair thought like what is the largest possible number, and writing a proof either for or against a value. Which wanders into heady territory fast (like a googleplex is 100 with a google of zeros written after it--for which there are some proofs on how long it would take to actually write a google of zeros . . . )Occupational hazard of my occupation not being around (sorry Bubba)
Mark Twain - 2 fathoms, 12' - the amount of water needed for a Mississippi River stern wheel steam boat to pass safely.
Also a vagarity of the way river soundings were made. Unlike an ocean going ship, where the leadman might have to get 20-30 fathoms of line and lead heaved ahead of position, the river leadman rarely needed more than a 15 fathom lead line.
The river lead man called in fathoms as "marks" and "halves." So, nine feet was "by the Mark, An' Halve!" Sam Clements' 12' foot was "By the Mark, Twain!" So, 15' was "By the Mark, Twain, an' Halve!" On some rivers, the leadman actually used a pole with marks and halves rabbeted into it.
Fathometer is so much more incredibly simpler, really. (And less dependant on a stout-armed person with great dexterity and depth perception.)Occupational hazard of my occupation not being around (sorry Bubba)
Wasn't knots had to due with knots on a rope that they used to throw over the side
Well, the original speed "logs" were lines with knots & attachments very similar to leadlines used to "sound" the bottom depth. The lines were coiled around a wooden shaft in a frame mounted/mountable near the stern of the vessel.
These were attached to a triangular bit of wood so that it would float. The float went into water and a sandglass was started. The line payed out until the time in the glass was reached. The length of line was then "read" by whatever length indicator was closest. Some speed logs had ratchets and pawls and even geard cranks to eas retrieval. The "float" end had a tapered peg that would unseat with a yank, making the log line easier to haul back aboard.
When clockwork became more common, a clever person worked out that spinning a bladed hub of known pitch & diameter could be converted into distance with gears and a dial indicator. The taffrail log was universally accepted as soon as it was available (not having to heave in all that line soaked in saltwater a definite benefit).Occupational hazard of my occupation not being around (sorry Bubba)
When I was in High School in the seventies I ran cross country. An official varsity course was 4.2 +/- .3 miles. The first year coach at a neighboring school, (who was the art teacher, who happened to jog, and was willing to take on coaching a non-glamour sport like cross country), laid out the course for the first home meet of the season at 4.29 miles, wandering through the woods.
About 25 minutes into this race my buddy and I are in the lead and trying to figure out where the finish line is. At 45 minutes we are feeling quite a bit of pain, and still no finish line, and we are hoping we didn't miss a turn flag and get lost. We walk for a bit, and some other guys catch up. We are all stopping and walking, asking each other if we are lost, but there are still flags so we keep following them. Suddenly we come out of the woods, and back onto the campus, and it is a mad dash of the finish line. We finally finished in an hour and twenty seven minutes.
Turns out this guy thought there were 10,000 feet in a mile, and laid out the course with a rollowheel. His 4.29 mile course was 8.125 miles long.
I recently moved to the west coast (a few years ago) and found that out here they also referred to nails as penny nails. In Ontario I can't remember when I last saw a smooth shanked penny nail. I guess the only ones were little finishing nails and even then most were what we called ardox. Here on Vancouver Island when I first asked for 3 inch nails they gave me smooth penny nails and when I asked for ardox they didn't know what I was talking about. Even when I do get 3 inch ardox nails they seem to look alot thinner than I remember out east but I've got nothing to compare them with.
Actually the US adopted the metric system officially ( read a great article on it) over 100 years ago but it was never implemented. Oh yes, out here in BC they still use and advertise in pounds and ounces far more than I have seen in Ontario. I actually thought it was against the law to advertise imperial weights and measures bolder than metric.
So many regional things to get your head around.
roger
So we can have a cup of water (8 ounces as measured in volume) and it actually weighs 8 ounces, but we can't have a 2 cup hammer.
Now that's funny right there!!
"Why the largest industrialized country in the world is still using antique systems of weights and measures completely baffles me. "
Don't worry, this problem will take care of itself. In ten years the largest industrialized country in the world will be using metric. China, that is...
;-)
I was under the impression that the penny size of a nail was an indicator of it's diameter not length - joist hanger nails are 10d x 1 1/2"
16d common are 3 1/2" while 16d sinkers are usually 3 1/4" although sinkers also have a smaller diameter than common, so who knows what the sizing stands for :)
I was under the impression that the penny size of a nail was an indicator of it's diameter not length - joist hanger nails are 10d x 1 1/2"
The penny number is an indicator of both diameter and length.
The reason that the joist hanger nails (for some reason they're known as Tecos (sp?) out where I live) are identified as 10d x 1-1/2" is that they're essentially a shortened 10d nail (10d would typically be a 3" nail). Joist hangers are designed to place the nails in shear, so that's why thicker nails are desired, of course.
< the penny number is an indicator of both diameter and length.>
Nope. length only.
One has to remember that when this all started nails were hand made,"cut nails " as we know them, there was no round nail, hence no wire size, they were all the same wire size, just varying lengths.
The terms box and common nail were used to denote wire size,later.
Box nails being used at the edge of a board, and being driven into the end grain of another board ( to make a box) were a smaller diameter to reduce the chance of splitting the boards, and why they are spec'ed for things like " 5d box nail for nailing beveled siding" or for applying exterior trim, less chance of splitting the wood.
Teco's are just a brand name of a joist hanger/nail manfacturer, the mis-use of the designation 10d x 1 1/2" is indeed to I.D. them as a larger dia. nail with a shorter length.
Geoff
Geoffrey,
Cut nails were mass produced by being sheared from sheet steel. They were 19th century products and were still made in the 20th
Early nails were forged one at a time.
Ron
Ron,
you're right, I kind of "squeezed" history a little, my point being we're not talking about "modern" round shank nails, but the originals, which were hand made, the "cut" nail actually coming later on and indeed being a mass produced product, but still not the round shank we know today.
Geoff
G,I'm looking at a table that is supposedly based on ASTM F 1667, "Standard Specification for Driven Fasteners: Nails, Spikes and Staples". Per the table, an ASTM F 1667 dash 11 steel nail gives the spec for a 16d common nail. The spec includes length, body diameter and head diameter. For box nails, the 16d has identical lengths and head diameters, but different body diameters, as you said, (0.135" for the box, 0.162" for the common). As a result, it looks like the penny weight designations, along w/ the type, should specify all dimensions of the nail.FWIW, the 16d joist hanger nail is the same diameter as the common, but one inch shorter.
Edited 6/15/2007 9:41 am ET by bd
One has to remember that when this all started nails were hand made,"cut nails " as we know them, there was no round nail, hence no wire size, they were all the same wire size, just varying lengths.
not exactly - as was mentioned, 19th century nails were sheared from hot sheets of steel - but they had different gauges since the sheets could be of varying thicknesses - so indeed there are cut 'box' nails, and cut 'framing' nails and as seemingly in all things 19th century, a grand plethora of specialty nails -
here's a great company that still manufactures cut nails - I keep a supply of various sizes and styles on hand, preferring to use them in cabinetry and also for face nailing floors -
http://www.tremontnail.com/
"there's enough for everyone"
Because when (in the 1970s) we tried to convert, we started using silly things like recipes that started off:
Stir together
236.59 ml of milk
4.92 cc of sugar
... etc.I'd gladly throw away all of my SAE socket wrenches tomorrow if it would help.To force me to think metric, I've purposely set my GPS to metric. Now it tells me "In 2 kilometers, turn right."91064.6 in reply to 91064.1 You have touched on one of my pet peeves. Why the largest industrialized country in the world is still using antique systems of weights and measures completely baffles me. And as an American, it actually embarrasses me.
American automotive uses both sizes, thats a lot of fun!, I wouldn't throw anything away.
Penny sizes are very strange. Box and common nails fo the same penny size have different diameters.
Nail gun nails often come in sizes that do not correspond to penny sizes.
We use these strange units because the people who use them are smart and have no need to dumb down the units.
It sucks. Why the housebuilding industry keeps this stuff in play for some of the key components of structure, is beyond me.
I prefer the descriptions for nails that the guys use that make spikes for air guns:
0.131 x 3-1/4 full head, brite
0.113 x 2-3/8 ringshank, galvanized
etc.
I guess we don't want to even mention "sinkers" where the 8d nail applied by hand is 2-1/2" long, but if it is a 8d sinker, it's only 2-3/8".
Maybe it has to do with how many syllables are contained in the name - it's easier to say 8d or just 8's than 2-1/2".
This theory certainly applies to framing lumber -- lots easier to say " hand me a 2x4 precut" than "hand me a 1-1/2 x 3-1/2 x 92-5/8" ". Yes, I know there are other precut lengths but I won't go there.
Jim
Never underestimate the value of a sharp pencil or good light.
Maybe it has to do with how many syllables are contained in the name - it's easier to say 8d or just 8's than 2-1/2".
I think there's actually a lot of truth to that. It's a lot easier to use a single term to describe nails (or a variety of other products).
With copper wiring, for example, we all specify by gauge, NOT the decimal diameter of the wire.
Sometimes the old systems can be wacky, but they're not entirely without merit.
copper wiring, for example, we all specify by gauge
Which makes some sense, since wire is "drawn" though a gauge to create it. If that gauged wire is stranded, the strands can make measureing the diameter problematic--unless you poke the cut end through a gauge.
In days of old, with natural-fiber rope, the measure was never diameter, but circumference. Hmm, my calculator ciphers that 12ga wire would be 0.253 circumference . . . Occupational hazard of my occupation not being around (sorry Bubba)
"This theory certainly applies to framing lumber -- lots easier to say " hand me a 2x4 precut" than "hand me a 1-1/2 x 3-1/2 x 92-5/8" ". Yes, I know there are other precut lengths but I won't go there."
here in Canada I guess it would be hand me that 38 mm x 89mm. (which is how it is listed in the code books)
personally I like using imperial and I don't really know why, other than it just relates better in my mind. I know what a 6' tall guy looks like. but if you told me a guy was 1.97 metres tall I'd be confused. I hate when stuff is denoted in metric even thought metric totally makes more sense. View Image View Image
I always like the term "bright, common" on nail boxes.
Kind of like Eliza in My Fair Lady
Forrest - All I want is a room somewhere, Far away from the cold night air -
Be carefull here. Next thing you know you will be giving away ardox nails, robertson screws and a few beers eh!
Have a good day
Cliffy
Thanks for all the replies/comments re 10d, 12d, etc. nail specifications in the U.S. versus Canada.
And for the correction to my mis-stating nail lengths as 10 'p', etc. instead of 'd'
Re the discussion/debate about whether the description 10d, etc. refers only to length or thickness: I only recall ever seeing the description in Fine Homebuilding and other articles as 10d, 12d, etc. to refer to length with no separate designation for the thickness of the nail.
In Canada the designations are typically common, finishing, Ardox (spiral), galvanized and some others for concrete nails (who still uses those instead of Tapcon screws?)
Thanks for all the replies and the 'other' threads from the original replies.