Metric or standard (SAE) bolt.....how to tell the difference quickly!

Excellent! And thank you for no seizure inducing annoying intro music.

"Grade" referres to Imperial bolts (Grade 5, Gade 8). Metric bolts are are "Class" (Class 8.8, Class 10.9). Further, the metric Class number has meaning.... i.e. with Class 8.8, multiply the first numeral by 100; gives the nominal tensile strength in MPa (800 MPA). Multiply the second numeral by 10; gives the nominal yield strength as a percentage of tensile strength (80% x 800 = 640MPA).

nice explanation and very well presented...if you are using fasteners a lot it is very useful to memorize what wenches and sockets interchange between SAE and Metric..eg i use 14mm when i need 9/16 as it fits nice and snug....a 1/2 inch wrench fits tighter on a 13mm bolt than a 13mm wrench etc...if you are desperate and need to remove an 18mm and only have a 3/4 or 19mm wrench, try slipping a dime between the wrench and the nut (open end only).

Here in the rust belt, beating on a socket from the other set because the original size is no longer going to turn it is standard practice. One mm increments are not fine enough, so I have .5 mm sockets for some popular sizes, too. Going to the tool box can be more complicated than just a metric/SAE choice.

This video is amazing all I need now is Time Machine to go back 50 years and someone still using imperial

I'm going to disagree with your assertion that 19mm isn't equal to3/4" close enough for them to be interchangable. There are 2 sizes I off the top of my head know are completely interchangeable, those being 13mm=1/3" and 19mm=3/4". The 3/4" being 0.05mm larger than 3/4" is not enough to call it a loose fit. 19mm is literally 0.002", or 2thou as a machinist would sat smaller than 19mm. That's within the tolerance range of most machined parts.

This is super informative! Thank you!

Here in europe, metric is the "standard". But we also accept imperial units "standard" for certain applications. Just a nitpick, good video again though. ;)

This video is very helpful the next time I see clean shiny bolts on a car I'm working on. Rule of thumb is, if made somewhere besides USA, it's all metric, made in USA after 1990 it could be both, made after 2010 it's metric, but in building ships in US it still could be both SAE and metric but most likely SAE.........

6 point sockets are handy because they make it easier to use on the wrong nuts and bolts. Might save you a trip if you have a 6 point metric that'll work on a standard.

metric = standard

Wow that makes sense now. In a standard metric country ive always wondered why some equipment and tools designed in America but sold internationally in metric had such odd nut bolt and screw sizes no-one would normally use like a 16 wrench. The designer still thinking old imperial sizes and finding the metric equivalent. Does this also extend to some of the odball metric units Americans sometimes use such as Calories and mols per decileter and always use milimeters and ignore all other prefixes thinking they different units. Just curious.

the REAL challenge is to identify BSA/UN/SAE from BSW at a glance. whitworth threads. like NPT from BSPT. 55 versus 60 degree "iso" flank angle. some of the finer pitches can be a bit tricky, gas and plumbing is a nightmare of standards and non standards, LH and RH, and short thread lengths you cant measure properly... M5x0.8mm looks a lot like a... 3/16-32 UNEF? 3/16=4.75mm, and 32TPI=0.794MM... but to me, UNC just looks... steeper. deeper threads.

When you get to looking at metric vs imperial thread sizes the worst has to be 6mm vs 1/4" they will start to go together but lock up after a few turns, that's when a gorilla swings on the wrench and starts to cause damage where using the right nut or bolt would have been so much easier.

The world is metric, only a small group of countries use inches, change and be happy, a clear system!

I've merged my wrenches/sockets together. They are sorted from smallest to largest. I use the smallest one that fits.

You would think with all the crap they stamp on the head... They could just stamp the size on there... 6 lines for grade 8, 3 lines for grade 5 no lines for grade 2 could this make any less sense... Who's on first what's on second 🤣🤦

Cool. Also, 22mm=7/8",19mm=3/4" and 5.5mm=7/32".

thank you, good video. i am waiting also for a video on thread sizes ;-) i have some experiences of trying to thrust a SAE bolt into a metric hole... and the difference between different step size in SAE bolts is a topic worth mentioning.

The rest of the the word still refers to it as "British Imperial Units" specifically because imperial isn't "standard", it's not "American" and the SAE is an organisation that actually makes useful metric standards, especially in Aeronautic and aerospace, but even in fluid power systems.