Name That Hardware

Hex-Head Screw

It’s been just more than a month since my backside found its way back into an editorial chair here at Popular Woodworking Magazine. We are about to wrap up the first issue since my return. That means the articles are in our binder and we read everything one additional time to make sure there are as few mistakes as possible before it goes to press then to you for your reading pleasure. (It’s your duty to find the one mistake we left in the magazine and that can only be accomplished if your read the entire issue from front to back.)

Reading binder is totally different for me this time around. My duties and responsibilities are different. But there are things that stay the same. As we read, we also discuss any concerns we find. Yesterday there were a few discussions, but the one that fascinated me the most was about hardware for a portable workbench top.

In the article text, the author, Christopher Schwarz, writes that the above-picture hardware is a hex-head bolt. Of course, with each round that label is challenged. We all call it a lag screw. Bob Lang and I say a bolt has a nut involved to make a connection and that a lag screw is what was used.

Via e-mail, Chris again defended his label and directed us to a home center to confirm – he used the term by which the piece was listed at the store at which he bought it. (The goal is to make it easy for readers to find the exact piece – be it screws, nails or drawer pulls – used in the article.) So check we did. Do you think you know the answer? Be careful.

Online at one store we found the terms “hex-head screw” and “lag screw” intermixed. At a second store, we found similar terminology and we found the hardware item pictured below.

Lag Bolt ?

Chris wasn’t wrong in how he listed the piece.

Is this what happens when store inventory is labeled by folks who don’t really know what the item is called? Or is this known as a hex-head bolt? Are the terms hex-head and lag, and bolt and screw interchangeable? Comments are open. Let’s hear your thoughts.

— Glen D. Huey

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67 thoughts on “Name That Hardware

  1. msiemsenmsiemsen

    Most workmen would call them “lags”, as in “hand me one of theose !/4 inch lags”. When they are used in conjunction with a lead or plastic “shield” in masonary they would be called a lag and shield. A shield could be reasonably compared to a nut. I find it odd that no one has mentioned that a bolt without a nut on it is properly called a machine screw, there is no point on the end of a 1/4-20 machine screw. Try posting a picture of a machine screw and see what response you get as to it’s proper name, screw or bolt.

    1. Robert W. Lang

      Excellent point Mike, it’s the nut on the end that determines the difference between a “bolt” and a “screw”. This was actually a side argument to the main discussion we had here in the office. Our debate was quite a sight to see; Megan reaching for her O.E.D. and me rifling through my copy of “Machinery’s Handbook”. Had Glen not beat me to the punch with his post, I would have posted scans of the appropriate pages.

      Bob Lang

  2. kct3937

    For 50 plus years, I have known these items as “Lag Bolts”. Sometimes today, you have to ask a youngster at the supply yard for a lag screw and many times it depends on the size of the item you are requesting. Never ask for it at Home Depot, unless you like blank stares. IMHO hex head has nothing to do with it as they have always been made that way and have alway been tightened with a socket drive or a wrench …which is not a place where jewish cowboys keep their cattle.

    Now if you want to call a square drive screw by it’s real name…Robertson things will be all right in the world 🙂

    May the scwartz be with you!

  3. marmadoon

    I would suggest that you separate the replies and see if there are differences in terminology by region.

  4. fltckr

    I did a search for USA made fasteners, and I found the following on a supplier’s site: “Hex Lag Screws (Bolts)”. So I guess they are bowing to the public’s perception of how they are described – smart choice. However, the American National Standards Institute (ANSI) and the American Society of Mechanical Engineers (ASME) call them “hex” or “square lag screws” – no compromising from the smart guys (since 1914 no less). I will personally think “screw” when I see a box of “hex lag screws (bolts)” from a USA manufacturer, or a box of “lag bolts” from a foreign maker. Does it matter? To me it does a little bit because there is a good reason for standardization, and it should not be ignored. Now, the comment about using wooden pegs instead of lag screws/bolts has me wondering. Should we use ANSI approved pegs/dowels or foreign made wood formed cylindrical fasteners? Seriously, I’m not being serious here….I’m not going to re-label my supply drawer.

  5. fltckr

    For what its worth: Machinery’s Handbook, 26th edition (2000) calls it a “Hex Lag screw” and the square head a “Sqare Lag Screw”, both with accompanying illustrations that leave no doubt of what they are describing . This is according to ANSI and ASME standards. The 1914 edition of Machinery’s handbook has a table of “Lag Screw Thread Sizes in Common Use”, and lists the same shank size and number of threads for a 1/4″ Lag screw as the 26th edition, so I don’t think anything has changed much since then except today most are made in China out of inferior steel and to much lower standards. So why did I label my supply drawer “Lag Bolts”? I think it is because the foreign manufacturer labeled the box according to their understanding. Had they been made in America, I’m willing to bet the box would have been labeled in accordance with ANSI/ASME standards e.g., “Hex Lag Screws”.
    My two cents…

  6. abt

    I’ve been labeling drawers for hardware and came across both label names for the same type of hardware when in the original bags. Both packages were vendor labeled, so even vendors may be confused.

  7. ronwood72

    I went with lag bolt, because you turn it with a wrench, any thing turned with a screw driver was a screw. I am betting this wasn’t the tie breaker.

  8. Richard Dawson

    In reference to Glen’s discussion of changing the clutterhead on a jointer, were there any lag bolts damaged in the filming of his enlightening video? (I always called it a planer.)

    Inquiring minds need to know.



  9. bubbainmiss

    Lag Screw or Lag Bolt–either one. Specifying “hex head” is both redundant and implies that it is a machine thread. What somebody at a home center chose to call it makes no difference. If they hung claw hammers under a sign that said “crowbars” would you tell your readers to drive their clinch nails home with their crowbars? Just show a picture of the correct fastener in the article.

  10. vdepauw

    Sorry but describing this as a hex headed bolt is totally wrong. The bolt would indicate a staright threaded shaft ment to screw or turn into a matching threaded hole and would need to be identified also by the threads per inch. This could be of any material wood throuh metal. The item illustrated has a shaft with a taper and is ment to turn into a non threaded hole in a softer material. It does not really cut a thread. Calling it a hex head is proper as the head has 6 flat sides. This screw can also come swith a square head, 4 flat sides.
    Vic De Pauw

  11. gdblake


    You and Bob are correct, screws have points, bolts tighten down via a nut. I don’t care what some back office idiot who doesn’t know what the item really is labels them for display or catalog purposes. Language is fluid and the meanings of words change over time because of ignorance and general disregard for convention. Words only mean things when the definitions stay constant. I find it odd that Chris would defend the use of bolt in this case when he is usually a stickler for using the proper term. Or does he only cut grooves now and done away with dados, rabbits, and filisters?

  12. oakripper

    I have always called this a lag screw because the threaded part comes to a point. When referring to the fastener with the eye or ring on the end, if it has a threaded end that comes to a point it is referred to as a eye-screw and if it uses a nut then it is referred to as a eye-bolt. just my 2 cents worth.

  13. Bernard Naish

    Traditionally called a coach screw here in England. Coach bolt has threaded portion to take a nut and a domed head with a square section under it that stops it turning. Lag screw not a description known here. Keep up the interest or all this will be lost. Regards to all.

  14. Ron 1

    I think number of years us old-timers have in the Trade should pretty much count towards the correct name. I have 50 years calling it a “Lag Bolt” or may have even called it a “Lag Screw”. Hell I don’t remember, the important thing is I know what I need, and that gets to be very important as you get older.

  15. Sawduster

    As a similar convention, when does the size and or thread count change its name from a machine screw which also includes a nut for closure to a bolt? Have just wondered and never gotten an answer.

  16. gazpal

    The piece of hardware pictured is a lag/coach/hex screw – it works in the same manner as a screw but you use a spanner or socket to turn it. A lag/coach/hex bolt passes all the way through the work piece and is secured using a nut.

  17. 7-Thumbs

    I’ve always called this a lag bolt. Personally, I wouldn’t trust any name a big box store put on their hardware.

  18. GregM

    My opinion is that this item is *correctly* called a “lag screw” but – in North America at least – also *commonly* called a “lag bolt”. I think the key word to include here is “lag”. If you ask for a “lag screw” or “lag bolt” you will most likely leave the store with the appropriate item. Readers in the UK or Australia may need a “coach bolt”, but here in the US that wouldn’t get you far since our coach bolts have round, domed heads that cannot be gripped or turned by a wrench (spanner).

    1. GregM

      I stand corrected (by myself). Carriage bolts have round, domed heads. I don’t know if there is a commonly understood US meaning for “coach bolt”.

  19. Bob Miller

    I read the magazine back to front and then to the back again. Is this still an acceptable method? Or am I skating my duty to find that one error by reading in reverse article order?

    I would if not thinking about it call it a “lag bolt” this is also what the rest of my family does. I think “hex head” is an acceptable prefix because regardless of its bold/screw/swirlything status it does have a hex head.

    I wonder are different naming conventions a regional thing and you would get 6 different answers from hardware stores in 6 different places.

  20. renaissancewwrenaissanceww

    Sounds like a perfect opportunity to sidestep the whole issue and use a wooden peg. Then you can call us Lie Nielsen or Veritas and pitch them on some ad space highlighting their dowel maker solutions conveniently placed adjacent to the article.

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