Bolt Head Markings: What do they mean? | Fasteners 101

Fasteners bear all forms of markings on their heads, from number and letters, to shapes and hash marks. But what do they mean? In this video our fastener specialist covers several more common head markings on bolts and what they can tell you about the fastener.
Got a handle on the different head markings on bolts? Than feel free to get your own here: www.albanycountyfasteners.com/hex-bolts-tap-and-hex-cap/277.htm
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For more Fasteners 101 information, please visit our website here: www.albanycountyfasteners.com/Fastener-Education-and-Information-s/1128.htm

Пікірлер: 121

  • @drgolfjim
    @drgolfjim Жыл бұрын

    Thank you for getting right to the point.

  • @JesseGunzo
    @JesseGunzo3 жыл бұрын

    Very useful info

  • @anthonytuck864
    @anthonytuck8645 жыл бұрын

    Great vid. One comment. The stainless bolts are not delineated by higher or lower grades. Each stainless alloy is typically designed to do a specific job in preventing corrosion. 304 is a basic 18/8 alloy that has a broad range of uses and is reasonably priced. 304 is also typically used in you house, kitchen sink, knives, forks etc. 316 has a small amount of molybdenum in it. Typically used in the food industry as it has excellent resistance to the acids found there. When using stainless bolts it is wise to understand strength of the specific alloys as their properties differ vastly from carbon steel bolts. The L appended to the end of the grade (IE: 304L) means that the alloy is low carbon and meets that specification. Happy days

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    5 жыл бұрын

    Very good information to add! Thank you for your feedback!

  • @creativity.studio4967

    @creativity.studio4967

    11 ай бұрын

    Thanks. I was wondering because he left out so much explanation that is needed.

  • @Mark-gf7nl
    @Mark-gf7nl4 жыл бұрын

    Great video! Thanks!

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    You're welcome! Thank you for your feedback.

  • @michaelwas8549
    @michaelwas85492 жыл бұрын

    Thank You!

  • @holliwood3226
    @holliwood32265 жыл бұрын

    IFI = Industrial Fasteners Institute. Just like any industry association their purpose is not to make it easy to decipher their markings. Hence "no marking = grade 2, 3 lines = grade 5, 6 lines = grade 8. Common sense does not apply when dealing with standards organizations.

  • @foodstuff778

    @foodstuff778

    5 ай бұрын

    Just add 2

  • @robertsims6136
    @robertsims6136 Жыл бұрын

    GOOD VIDEO. TY

  • @robwilgenhof4386
    @robwilgenhof43862 жыл бұрын

    Thank you sir

  • @bubblywaters3116
    @bubblywaters31162 жыл бұрын

    I just learned that you add 2 to the number of slashes on a bolt head to get the grade. 3 slashes add 2 and you have a 5 grade. Pretty cool. Always add 2 to the number of slashes for actual grade.

  • @francoamerican4632

    @francoamerican4632

    Жыл бұрын

    This might seem like a radical concept, but wouldn't it make more sense to use five marks for a grade 5 bolt, eight marks for a grade 8 bolt, etc.

  • @kandasamyrajan
    @kandasamyrajan6 жыл бұрын

    Thanks

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    5 жыл бұрын

    Your welcome!

  • @adambananas7741
    @adambananas77414 жыл бұрын

    Great video. Thank you.

  • @MoeLykit
    @MoeLykit2 жыл бұрын

    The Letter Codes on Bolts at Big Box stores from Bulk displays are Speed Codes for the Cashier to be able to identify them at the register

  • @dancorwin9232
    @dancorwin92324 жыл бұрын

    speed x 1.25. you're welcome

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    Thank you for your feedback.

  • @brunotulliani

    @brunotulliani

    3 жыл бұрын

    Used a box of tissues because I was laughing so hard! It was better at 1.25x. You rock!

  • @rickyhall1772

    @rickyhall1772

    3 жыл бұрын

    Lol

  • @bullfrogpondshop3179

    @bullfrogpondshop3179

    10 ай бұрын

    1.75 worked for me

  • @doncallangher6177
    @doncallangher61772 жыл бұрын

    Thanks for clearing this up for me, its something I've wanted to know since adolescence but too lazy too look up. So I guess, when in doubt, get a bolt with as many slashes as possible!

  • @danielnegrao6648
    @danielnegrao66483 жыл бұрын

    Is cool, how about metric bolts? And Astm?

  • @fredytay2122
    @fredytay21223 жыл бұрын

    Thanks😎

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    3 жыл бұрын

    You're welcome! Thank you for your feedback!

  • @solobassoon
    @solobassoon2 жыл бұрын

    I have a specification on bolts saying: 'STUD BOLTS C/W 2 A4-70, ISO 3506-2, SF, HH...etc...'. May I ask what does 'SF' and 'HH' stand for?

  • @FEDAMachine
    @FEDAMachine2 жыл бұрын

    Nice

  • @randygomez952
    @randygomez9523 жыл бұрын

    This is absolutely fascinating lol

  • @dnolder1
    @dnolder15 жыл бұрын

    Thanks for answer on stainless bolts. I was just trying t figure where in automotive use I could use them. What are grade 2 bolts in comparison to tensile strength. Thanks

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    5 жыл бұрын

    The Tensile strength of a Grade 2 bolt may vary slightly depending on size but will generally be about 74,000 PSI (1/4" - 3/4" Nominal) or 60,000 PSI (3/4" - 1-1/2" Nominal).

  • @houndsmanone4563

    @houndsmanone4563

    3 жыл бұрын

    dnolder1, I don't know the tensile strength of grade 2 bolt but the fact that it has a lessor tensile strength saved my expensive rotary cutter when the blades hit a big stump in the ground. That single little bolt is the sacrificial part of my cutter therefore, I carry additional grade 2 bolts when cutting. Sorry, I know this didn't answer your tensile question but your question gave me a flash-back of when the snapped bolt saved my cutter. 🙂

  • @me1assassin
    @me1assassin3 жыл бұрын

    How about "7T DS" where the 7T is abve the DS. Closest I coe is JIS, but appears non-metric 5/8-18? Very Confusig (on a tractor wheel stud)

  • @ckinc89
    @ckinc893 жыл бұрын

    Thank Q

  • @xiaohou8830
    @xiaohou88304 жыл бұрын

    I just purchased a standard GR 5 hex cap bolt from Fastenal and the mfg marking is FNL. Except for the FNL and the 3 strike marking, the head also has "HT". I checked the SAE J429 and did not see anything mentioned about such marking. Could it be "JH" as "FNL" is a sub-company of "JH"?

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    Possibly. Markings beyond grade or material markings vary from manufacturer to manufacturer.

  • @CaniLupine
    @CaniLupine2 жыл бұрын

    I have metric bolts with 4 lines that secure my bottom motor mount, and I can't find any information on them.

  • @frankd.brennan6520
    @frankd.brennan65204 жыл бұрын

    Can I use a stronger bolt for a head gasket on a car

  • @thefogisgone3662
    @thefogisgone36623 жыл бұрын

    Hello bob, the head markings expert haha

  • @noekimes1887
    @noekimes18873 жыл бұрын

    What do that markings (F593G316 THE) mean?

  • @hoey3510
    @hoey35102 жыл бұрын

    Could some explain what f and 7 lines on a 5/16 unc bolt mean? Does it mean is stronger than a 6 line grade 8 bolt?

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    2 жыл бұрын

    F is the manufacture mark and 7 marks may be OME made.

  • @justinc9911
    @justinc99114 жыл бұрын

    nice to know, I have a bolt with "h110" on it? what does the "h110 stand for?

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    Sounds like that might be a manufacturer's marking. What kind of bolt is it?

  • @iamoutofideas13
    @iamoutofideas132 жыл бұрын

    Can you tell what the equivalent grade strength of a stainless steel bolt is by reading the markings on the head of the bolt?

  • @therealcfiddy592

    @therealcfiddy592

    6 ай бұрын

    No

  • @dnolder1
    @dnolder15 жыл бұрын

    How would you know what hardness a stainless steel bolt is?

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    5 жыл бұрын

    There is no hardness to stainless steel and has no rating. Grade 8 bolts have a proof load of 120,000 pounds per square inch. The minimum strength of stainless steel bolts is 40,000 to 90,000 psi. The minimum strength of grade 8 bolts is 130,000 psi. Grade 8 bolts are much stronger than stainless steel.

  • @jonathantan8528
    @jonathantan85282 жыл бұрын

    What does a 4.8 marking mean?

  • @crabjoe
    @crabjoe4 жыл бұрын

    What is the difference between an A2 and A4 bolt? I replaced a bolt marked SRS 8.8 with one marked XXYX A2 S304. I was told to find one marked A4, but A2 was all I could fine. This is going to see a lot of road salt in the winters. The bolt is used to keep a DEF injector mounted to a diesel exhaust system. I figured any stainless bolt would be better than a carbide steel bolt, which I think was originally in there.

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    You're gonna want to find an A4 bolt to replace that A2 then. A4 is the metric equivalent to 316 stainless steel and A2 is the metric equivalent to 304 stainless steel. A4/316 stainless steel bolts are very corrosion resistant and are intended to be used in areas of high corrosion such as near salt water or heavily salted roads.

  • @crabjoe

    @crabjoe

    4 жыл бұрын

    @@AlbanyCountyFasteners Thank you.

  • @REVOLUTIONS51

    @REVOLUTIONS51

    2 жыл бұрын

    @@AlbanyCountyFasteners 304 are actually more corrosion resistant in many environment, especially near sea water.

  • @OmarTheAtheistAziz
    @OmarTheAtheistAziz3 жыл бұрын

    Any way to buy a bolt knowing the girth of the threads, & the length of the bolt?

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    3 жыл бұрын

    If by "girth" you mean diameter then yes! Bolts are sized based on their Diameter-Thread Pitch x Length. For example, a 1/4"-20 x 3" FT Bolt has a 1/4" diameter with 20 threads per inch and is 3" long, full threaded.

  • @Finlandiabeach
    @Finlandiabeach4 жыл бұрын

    I have purchased Bolts marked "Fed-Alloy" With 12 markings. They were sold to me by Acklands-Grainger Industrial supply on sale. Are they the strongest bolts available?

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    The "strongest" bolts for commercial uses are usually Grade 8 (US) and Class 10.9 (Metric). We say "strongest" because a strong bolt can mean many different things. As far as the numbers go, these two boast the highest proof load, yield strength, & tensile strength of commercial grade bolts at the expense of ductility and a higher chance of fatigue failure over time. However, stainless steel bolts, while weaker in the numbers that make grade 8 and class 10.9 strong, have much higher corrosion resistance and can even resist salt water if the right grade of stainless is used. How do you define the strongest bolt?

  • @Finlandiabeach

    @Finlandiabeach

    4 жыл бұрын

    @@AlbanyCountyFasteners Thanks for your response.

  • @rickyhall1772

    @rickyhall1772

    3 жыл бұрын

    Any bolt with more than 6 slashes usually indicates an alloy steel bolt or 'grade 9' bolt. They are comparable in strength to metric 12.9 bolts, but they are much harder to find.

  • @andreazappaterra6763
    @andreazappaterra67632 жыл бұрын

    What is the acronym or the name company of JDF? Thanks

  • @kiengmeng7789
    @kiengmeng77895 жыл бұрын

    Could you help me explain about symbol M, 8.8, and MICon cap bolt of china product?

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    5 жыл бұрын

    The M means it's a metric bolt. The 8.8 is the grade and material of the bolt, in this case, carbon steel. The first digit relates to the minimum tensile strength of the material in megapascals (MPa), so that would be 800MPa, and the second is the yield strength in percentage, so that would be 80%. Lastly, MICon is the manufacturer's stamp.

  • @friedensreich61

    @friedensreich61

    4 жыл бұрын

    @@AlbanyCountyFasteners I think I have a misunderstanding here. What I hear you saying is: Ultimate tensile strength (UTS) = 8 N/mm^2 = 8 MPa and YS/UTS = 0.08. Both does not make sense. Could you please clarify what you actually mean.

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    @@friedensreich61 Hm...that response may have been in error. We've updated the comment to clarify what the 8.8 represents. We apologize for the confusion!

  • @friedensreich61

    @friedensreich61

    4 жыл бұрын

    @@AlbanyCountyFasteners thanks for the quick clarification. I would even formulate that the first digit is the min. tensile strength in 'hundreds' MPa and the second is the ratio 'tens' of percent. But with the numbers you provided, very clear indeed.

  • @gsh319
    @gsh3193 жыл бұрын

    Said a lot but learned just a little..... I knew this info coming in, thought there’s more to learn.

  • @phiethoangthe7053
    @phiethoangthe70532 жыл бұрын

    I have a bolt with big letter H on Head, what does it mean? Thanks

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    2 жыл бұрын

    Manufacture marking

  • @lofivibes-techanimestudios281
    @lofivibes-techanimestudios2815 ай бұрын

    Hi, I am new in the fastener sales journey and I'd politely ask for advice to where start Selling Stainless Steel Fasteners :)

  • @davidbigelow5852
    @davidbigelow5852 Жыл бұрын

    The logo on the last Bolt is for Viraj Profiles out of India

  • @francoistombe
    @francoistombe10 ай бұрын

    I have a bolt with 12 radial marks and an F in the centre. Where does this go on the ranking?

  • @macbethdemilo7253
    @macbethdemilo72532 ай бұрын

    My stainless steel hex bolt has no dashes. Its has F593C JBK THE on the head. What grade is this bolt? Grade 2 since it has no dashes or something else? Thanks.

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    2 ай бұрын

    Correct! JBK THE is the manufacturer

  • @macbethdemilo7253

    @macbethdemilo7253

    2 ай бұрын

    @@AlbanyCountyFasteners thank you, I got confused with the "grade 2" = no markings, and thought "but it has letters and numbers. I just wished there was a chart explaining what the F593C means.

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    2 ай бұрын

    Non available

  • @jacobhald1377
    @jacobhald1377 Жыл бұрын

    As a european, used to the metric bolt markings, this seems so hard to grasp. 3 slashes grade 5, 6 slashes grade 8? Why not 5 slashes grade 5 and 8 slashes grade 8? The stainless marking however, makes sense i guess ^_^ Either way, good video, and now, should i ever happen to be in the USA, i would know my way around bolts! :D

  • @rickconstant6106
    @rickconstant61062 жыл бұрын

    You don't mention metric bolts at all, which have a numerical system for identifying grades. Even in the US, most cars now are built using metric fasteners.

  • @francoamerican4632

    @francoamerican4632

    Жыл бұрын

    Someday the rest of the world will come to their senses and convert to the system that is being used in the US.

  • @UnknownUzer
    @UnknownUzer3 жыл бұрын

    I came here hoping to find out the differences between the types of bolts, but all the information I got was how to convert slash marks into a number, but no actual useful information such as the strength differences

  • @honda110wave2
    @honda110wave2 Жыл бұрын

    i really like bolts us torque specs

  • @sanbell6951
    @sanbell695110 ай бұрын

    All my garden tools are 304s

  • @timlower89
    @timlower893 жыл бұрын

    Just curious, is there a reason they complicate bolt markings? 3=5, 6=8. What’s the philosophy behind this, instead of just saying 3 is not as strong as a 6? Normally there’s a reason behind it, so just curious. Funny how bolts go up in numbers when stronger, but in electrical wiring the thicker the wire the lower the number. Sorry to be a pain in the ass, one of those questions that always makes me scratch my head.

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    3 жыл бұрын

    The grade markings were decided by the Society of Automotive Engineers (SAE) under their J429 specification. As far as we're aware, there's no particular reason that they are set up this way; it's just what SAE decided on when they made that spec. The general rule of thumb is that the grade is 2 less than the number of marks. Sorry this isn't exactly the most informative answer. I can't find anything about why those numbers of markings were chosen specifically.

  • @billhamilton2366
    @billhamilton23664 жыл бұрын

    Nicely manicured hands of the presenter.

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    Thank you for your feedback.

  • @RespawnRestricted
    @RespawnRestricted3 жыл бұрын

    I have alot that have 8.8 on them is that grade 8.8?

  • @rickyhall1772

    @rickyhall1772

    3 жыл бұрын

    Metric grade 8.8 is similar to an sae grade 5 bolt.

  • @DaveM2
    @DaveM22 жыл бұрын

    Manifacture?

  • @markharrisllb
    @markharrisllb3 жыл бұрын

    Are these international marking or just American please?

  • @rickyhall1772

    @rickyhall1772

    3 жыл бұрын

    They are sae or American bolt markings. Although some metric like torx and e-torx are starting to use the same slash marks to indicate strength.

  • @honda110wave2
    @honda110wave225 күн бұрын

    bolts united star number one

  • @victorvillacis6764
    @victorvillacis6764 Жыл бұрын

    its 3am in the morning and I am learning about bolts.....I work in software smh lol

  • @henryarce6547
    @henryarce65479 ай бұрын

    Quarter 20 cap?

  • @chadbosko8935
    @chadbosko89352 жыл бұрын

    You don't seem to be telling us what the different grades mean, say what 6 lines and a P would mean,I just took it from the auger on my snowblower, I am thinking this is not a shear bolt, there is no groove in the bolt, help

  • @xxdemonshitxx
    @xxdemonshitxx2 жыл бұрын

    I see E11 CS a lot on the bolts I work with....no lines...just those characters...

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    2 жыл бұрын

    Manufacturers markings.

  • @JustMe-uk9fb
    @JustMe-uk9fb6 ай бұрын

    👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻

  • @t0mn8r35
    @t0mn8r353 ай бұрын

    This would have been a better presentation if you had mentioned typical applications for each type of bolt.

  • @Lotrioni
    @Lotrioni4 жыл бұрын

    First thing first. What is IFI

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    IFI is the Industrial Fasteners Institute. They help define many fastener standards and their reference guides are often used by engineers to check fastener specifications.

  • @DonnieBeaver-j3g
    @DonnieBeaver-j3g18 күн бұрын

    Don’t you mean hex head cap screw?

  • @hussainali9999
    @hussainali99993 жыл бұрын

    Standard engineers “let us make something to make there life harder” ok let’s make unreadable marking on bolts heads

  • @richardtemby4358
    @richardtemby43583 жыл бұрын

    It would have helped if you explained the various grades by number or maybe you are not familiar with them. Just sayin!!!

  • @woofdoogy
    @woofdoogy3 жыл бұрын

    Mannnafature mahhkings

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    3 жыл бұрын

    Thank you for your feedback.

  • @karenhill3356

    @karenhill3356

    3 жыл бұрын

    When you get back from the Capital...

  • @DUNEATV
    @DUNEATV3 жыл бұрын

    Ehhh forget about it....

  • @willsrestorations
    @willsrestorations4 жыл бұрын

    For six and a half minute video you gave almost zero information. it would have been nice to let everyone know what the strength of the bolts are what they could be used for, weather the automotive or if it's corrosive or non corrosive.

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    4 жыл бұрын

    Thank you for your feedback.

  • @user-yz8gb6zt9c
    @user-yz8gb6zt9c Жыл бұрын

    Hi, can i ask what difference between FKE and VIBO?

  • @r.handoko7775
    @r.handoko77755 жыл бұрын

    That product manufactur from.china

  • @AlbanyCountyFasteners

    @AlbanyCountyFasteners

    5 жыл бұрын

    Thank you for your feedback.

  • @donsimons9810

    @donsimons9810

    3 жыл бұрын

    Designed elsewhere.

  • @hyperhektor7733
    @hyperhektor77333 жыл бұрын

    3 slashes grade 5 6 slashes grade 8 yeah american measurement systems xD

  • @lacausa2000

    @lacausa2000

    3 жыл бұрын

    Our measuring system is called the Imperial Measurement System - it was developed by the English

  • @hyperhektor7733

    @hyperhektor7733

    3 жыл бұрын

    @@lacausa2000 i know and i feel empathy for you :), (i am lucky i need this just for plumbing, you need it for everyday stuff)

  • @rickyhall1772

    @rickyhall1772

    3 жыл бұрын

    Well in terms of bolts, metric have 5.8, 8.8, 10.9, and 12.9. can you explain what the decimals indicate? Because they don't indicate tensile strength, so they could have picked 5, 8, 10 and 12 just like sae picked 2, 5, 8 and 9

  • @zzzyyyzz
    @zzzyyyzz2 жыл бұрын

    only american bolts here..

  • @bonlappen3000
    @bonlappen30002 жыл бұрын

    There's no logic to that! 3 marks should be grade 3 and 5 should be 5 and so on

  • @car5car5
    @car5car52 жыл бұрын

    The guy has very high blood pressure and partially blocked neck arteries. This should explain his zero knowledge of metric markings, which I really needed to know. So stop eating junk and make video about metric bolts.