Great to see it demonstrated. Something that could help a lot of people is to learn about pre-tension. In particular, when someone uses their ugga-dugga power tool to put their wheel lug nuts on, and they torque those suckers up to 300+ ft-lbs instead of the intended ~100 ft-lbs and then when going around a corner their wheel falls off and they wonder why the lugs broke.
Can you do a video about how to specify the correct bolt torque when designing a new thing. Walk us through the rationale behind TTY, Torque + Angle, or simple Torque specification. How much clamping load do I need? How does direction of force (normal, sheer, hybrid) dictate the prescribed clamping load.
Those are great questions and topics covered in a typical junior level mechanical engineering class once you have some foundations to properly apply the theories involved.
As a dude who 3D prints stuff I design this kind of expanded explanation around what is a really simple concept is super helpful because engineers are often grumpy. Subscribed.
Stunning!!! There are no words. This is what kids and people should be doing. This makes my brain reverser enginneer engines and thinking of ford 6.0 engine and their failing head bolts that need to be studded. Wow!!!!!
This is only part of the picture. Besides the static failure, the designer should also consider the amount of acceleration, bolt pre-load, application environment and many more factors.
Your question leads you into the field of statics where you learn to analyze all forces on a system. From this analysis, you would know the force on each fastener and if it was distributed proportional or not.
One press channel made comparison between different grade bolts and the results showed higher grade bolts just snapped more violently when certain threshold was reached. I personally would not even know where to buy anything less than grade 8
Great video! However, how does the threading factor into the yield strength? For example, if it were hanging by one thread, it’s not going to hold like you say. Also, the experiments showed the threads breaking before the bolt as might be expected. How do we dearth for threads, or, how many threads do we need to ensure the maximum pull performance? Related question, how much of the yield strength performance is provided by a ‘standard’ nut meant to work with that bolt (obviously if one used a grade 2 nut with a grade 8 bolt we should not expect top performance. This could be a whole video! ;-)
Great questions. Do a little research on number of threads required for maximum hold and you will be surprised. The technical answer can be found here www.engineersedge.com/thread_strength/thread_minimum_length_engagement.htm and a more general answer here www.fieldfastener.com/blog/2018/03/13/rules-of-thumb-for-thread-engagement
Great questions. In the sort term, the answer is no. But, if the application continually stretches and releases the fastener (or piece of metal) within the elastic zone, over time you start to worry about fatigue which does impact strength. Considering fatigue when designing is a field all of its own.
So what you’re telling me is that the grade 12.x ( I think it was 12.8) bolt I bought from Ace Hardware should be fine to hold my brake caliper bracket? Loved learning through your video!!
This was a more interesting video than expected - You should have put a picture of your tensile test rig in the thumbnail, I thought this was going to be a purely theoretical discussion but no, you actually tested this!
You mentioned there is a multiplier for each size bolt to correctly calculate max tensile strength. Is there a chart with that information to quickly calculate tensile strengths?
The Engineering Tool Box site has a detailed explanation of the Tensile Stress Area is (www.engineeringtoolbox.com/bolt-stretching-d_1164.html ) and you can find numerous tables such as this one (www.engineersedge.com/hardware/bolt_root_and_tensile_stress_area_15776.htm )
@NCSUMES so in a structural application could an SAE bolt be substituted for a ASTM bolt? My understanding was grade 8 was for mechanical applications and A325 or A490 were for structural applications
The theory comes from Materials Engineering or Materials Science, but it is used extensively in any engineering discipline dealing with the safe design of parts under load, such as Mechanical, Aerospace, Civil, Biomedical, etc.
Assuming you mean pulling a fastener into the plastic (yield) region and then releasing it, not re-pulling the broken one: Once anything is plastically deformed, it has a permanent change of shape. In this example, first look at the horizontal axis on the graph (length). The bolt will spring back the length of the elastic part of the curve, but stay permanently longer by the length of however far it got into the plastic part of the curve. It will now be work hardened (strain hardened) so on the second pull, it will stretch in the elastic part of the curve until approximately the same force that it was pulled to the first time. On a graph of the second pull, that means the height (vertical axis) where the curve changes slope is about the same height as the final height of the curve from the first pull. However, the amount of plastic deformation before it necks (length of the plastic part of the curve where the force is still rising, before the curve drops and the part weakens before breaking) is a limited amount, called elongation to break. So if a sample part has 10mm of elongation at break, and you plastically stretch it 4mm, you can only plastically stretch it 6mm next time before it breaks instead of 10mm.
Different types of fasteners respond differently based on the kind of material they are made from and the heat treatment they undergo. But no matter what, going past the yield point changes the fastener forever. Without intervention, it will never act the same again.
Yes it sure does and comes into the equation in the Tensile Stress Area. You can find it in a table such as this (www.engineersedge.com/fastener_thread_stress_area.htm). For our example a 1/4-20 = .031in^2 and 1/4-28 is .036in^2. So, ultimate force is 4,650 lb for 1/4-20 and 5,400 lb for 1/4-28.
Knowing how to calculate the strength of this type of fastener reveals how much weaaker it is than the straight tensile strength would imply. This is why deaign is best left to specialists and experts.
I'm curious, where did you get the ''reveals how much weaker it is than the straight tensile strength would imply'' part? What is the tensile strength value implying? If you mean someone seeing 150,000 PSI and thinking it can hold 150,000 lbf then that would just be out of this world dumb. Unless you mean something else?
@@Orgakoyd I've definitely met people who look at the chart, see large numbers like 150,000 and immediately think a bolt can support the weight of an entire semi including loaded trailer. I've also seen people make assumptions like using the area of the head of the bolt, nominal thickness, etc. It turns out things can be more complicated and its worth consulting with someone who knows what they're talking about.
@@Orgakoyd The reveals are standard charts for engineering standards. Tensile strength represents the minimum load you can apply without the fastener breaking. If you apply any load over the Minimum Tensile Strength, there is no guarantee the fastener will not break. Theoretically, you could go up to the minimum tensile strength without the part breaking, but in normal circumstances, you would not want to. As soon as your load passes the yield point, the fastener is permanently damaged (bent - out of the elastic zone) and will never perform the same again. In Engineering, we do not design things to break or only be good for one use. We design things so the load stays down in the safe working range. We add safety factors and do our best to ensure the load never exceeds the yield point. A scene from Apolo 13 comes to mind. Watch it if you have not!. They are trying to design a way to get the stranded astronauts home. The manager asks the engineers if a device can do something. They respond, "It was not designed to do that." He responds with, "I don't care what it is designed to do (with safety factors staying away from the yield point), I want to know what it can do (one time to get the people home even if we have to go close to the yield point."
@@NCSUMESto which a good engineer would have answered something along the lines " 95 out 100 bolts will hold 200 pounds or more of additional load before yielding, while 5 out 100 will hold between 100 and 200 more. 1 out of 10'000 yielded at only 5 pounds over the limit. How lucky do you feel?"
You were supposed to learn that Grade matters. You might also have learned that bolts tend to snap at the threads. You might have learned that there is a special "area" for threaded fasteners. You might also have learned a whole bunch of basic engineering terms and concepts. Maybe watch again?
I think some people who watch this may learn that for a threaded joint the strength is calculated by the TENSILE STRENGTH AREA and not the cross-sectional/diametral area of the fastener.
I love youtube suggesting 48 subscriber accounts with such great information, thank you William!
Indeed a gem! Cheers to the author 👌
Always means you've just stumbled on some top tier shit!
Now 175.
It's like they know me better than i do
The algorithm is blessing us with this content, and the author with subs - about 200 more since Greg's comment two weeks ago 🎉
Boeing utilizes whatever fasteners are in stock at Lowe’s.
I think that's Northrup Gruman. Boeing SOP is to check Home Depot pricing against Amazon.
Boeing uses the right bolt it’s just that their employees are all high.
Boeing doesn’t use any bolts at all.
They HAVE the bolts but they left them on the toolbox tray, it was just before break so no sense walking down just to get them.@N8SRQ 😮
Boeing fired all their union employees when they closed their plants they should be fine with lower quality workers right?
Gosh. This is the type of thing that interest me. Tensile, Compression, Shear. All good stuff.
Great to see it demonstrated.
Something that could help a lot of people is to learn about pre-tension.
In particular, when someone uses their ugga-dugga power tool to put their wheel lug nuts on, and they torque those suckers up to 300+ ft-lbs instead of the intended ~100 ft-lbs and then when going around a corner their wheel falls off and they wonder why the lugs broke.
Can't believe there was a practical demonstration. Bravo!
Can you do a video about how to specify the correct bolt torque when designing a new thing. Walk us through the rationale behind TTY, Torque + Angle, or simple Torque specification. How much clamping load do I need? How does direction of force (normal, sheer, hybrid) dictate the prescribed clamping load.
Those are great questions and topics covered in a typical junior level mechanical engineering class once you have some foundations to properly apply the theories involved.
Tighten until you hear a popping noise and the fastener spins freely, then ask the apprentice to torque everything down.
This is great stuff! I loved my applied materials and statics classes, we got to do these kind of test in labs.
classic first year engineering stuff, so applicable
As a dude who 3D prints stuff I design this kind of expanded explanation around what is a really simple concept is super helpful because engineers are often grumpy. Subscribed.
It would be fascinating to hear about the metallurgy for TTY bolts that operate in the yield zone, such as TTY head bolts used on some motors.
Im subscriber 291. Ill never forget the day I subscribed to "Wild" Bill Fortney.
605
Great video! Love the format and the demonstration!
Thank you respectable bigga
Stunning!!! There are no words. This is what kids and people should be doing. This makes my brain reverser enginneer engines and thinking of ford 6.0 engine and their failing head bolts that need to be studded. Wow!!!!!
Thank you! Great channel. I used to make structural drawings for high rise buildings.
This is only part of the picture.
Besides the static failure, the designer should also consider the amount of acceleration, bolt pre-load, application environment and many more factors.
Great way to teach laypeople the language and engineering. I learned "elastic" and "plastic" as it relates to material science!
Nice demonstration. This is why I use fine thread fasteners with as little thread as possible on my race cars
Awesome video! I will be watching more.
is the load proportionally distributed with additional fasteners? does two bolts have double the strength?
Your question leads you into the field of statics where you learn to analyze all forces on a system. From this analysis, you would know the force on each fastener and if it was distributed proportional or not.
Bluehill... I remember that software. Something about v2 being completely incompatible with v3, but i could be way off.
Nice video and explanation!
Haha I love the idea that somebody would try to lift nearly two tons with a 1/4-20 bolt
One press channel made comparison between different grade bolts and the results showed higher grade bolts just snapped more violently when certain threshold was reached. I personally would not even know where to buy anything less than grade 8
Big box home improvement stores.
Now please do a worn serpentine belt on the lifting diagram!
I love youtube recommending 644 subscriber accounts with such great information.
0:05 I don't need friends to have crazy ideas 🤪
Great video! However, how does the threading factor into the yield strength? For example, if it were hanging by one thread, it’s not going to hold like you say. Also, the experiments showed the threads breaking before the bolt as might be expected. How do we dearth for threads, or, how many threads do we need to ensure the maximum pull performance? Related question, how much of the yield strength performance is provided by a ‘standard’ nut meant to work with that bolt (obviously if one used a grade 2 nut with a grade 8 bolt we should not expect top performance. This could be a whole video! ;-)
Great questions. Do a little research on number of threads required for maximum hold and you will be surprised. The technical answer can be found here
www.engineersedge.com/thread_strength/thread_minimum_length_engagement.htm
and a more general answer here www.fieldfastener.com/blog/2018/03/13/rules-of-thumb-for-thread-engagement
I knew all of this information, I have no idea why I just watched this 😂
Does elasticity degrade its load capability over time or no?
Great questions. In the sort term, the answer is no. But, if the application continually stretches and releases the fastener (or piece of metal) within the elastic zone, over time you start to worry about fatigue which does impact strength. Considering fatigue when designing is a field all of its own.
Nice information.
So what you’re telling me is that the grade 12.x ( I think it was 12.8) bolt I bought from Ace Hardware should be fine to hold my brake caliper bracket? Loved learning through your video!!
Is there any advantage to use studs with two nuts instead of a bolt and one nut in terms of strength?
Real question is what's the production cost difference between them why make lower grade bolts at all ?
Great video
Cool. Can you make a metric version of this video?
Enlightening
Would need to watch this in metric😂
This was a more interesting video than expected - You should have put a picture of your tensile test rig in the thumbnail, I thought this was going to be a purely theoretical discussion but no, you actually tested this!
Looks like he listened!
That spec sheet, why can’t it give that number you calculated?
You're using a 1/4-in bolt to hold almost a 2-ton load? That's insane. I would never do this with anything less than a 17/64 size bolt.
You mentioned there is a multiplier for each size bolt to correctly calculate max tensile strength. Is there a chart with that information to quickly calculate tensile strengths?
The Engineering Tool Box site has a detailed explanation of the Tensile Stress Area is (www.engineeringtoolbox.com/bolt-stretching-d_1164.html ) and you can find numerous tables such as this one (www.engineersedge.com/hardware/bolt_root_and_tensile_stress_area_15776.htm )
What about the difference between a Grade 8 and an A490? Or SAE bolts vs ASTM bolts?
Same calculations, but you get their specifications for ultimate and yield stress from a standards table.
@NCSUMES so in a structural application could an SAE bolt be substituted for a ASTM bolt? My understanding was grade 8 was for mechanical applications and A325 or A490 were for structural applications
sounds like your friend learned a bard lesson
what field study is this in? Mechanical engineering ?
The theory comes from Materials Engineering or Materials Science, but it is used extensively in any engineering discipline dealing with the safe design of parts under load, such as Mechanical, Aerospace, Civil, Biomedical, etc.
What about a second pull? After a fastener has entered its yield region, what happens then?
Assuming you mean pulling a fastener into the plastic (yield) region and then releasing it, not re-pulling the broken one: Once anything is plastically deformed, it has a permanent change of shape. In this example, first look at the horizontal axis on the graph (length). The bolt will spring back the length of the elastic part of the curve, but stay permanently longer by the length of however far it got into the plastic part of the curve. It will now be work hardened (strain hardened) so on the second pull, it will stretch in the elastic part of the curve until approximately the same force that it was pulled to the first time. On a graph of the second pull, that means the height (vertical axis) where the curve changes slope is about the same height as the final height of the curve from the first pull. However, the amount of plastic deformation before it necks (length of the plastic part of the curve where the force is still rising, before the curve drops and the part weakens before breaking) is a limited amount, called elongation to break. So if a sample part has 10mm of elongation at break, and you plastically stretch it 4mm, you can only plastically stretch it 6mm next time before it breaks instead of 10mm.
Different types of fasteners respond differently based on the kind of material they are made from and the heat treatment they undergo. But no matter what, going past the yield point changes the fastener forever. Without intervention, it will never act the same again.
does the tread type have an impact 1/4 unc /unf? (1/4- 20 and 1/4- 28 tpi)
Yes it sure does and comes into the equation in the Tensile Stress Area. You can find it in a table such as this (www.engineersedge.com/fastener_thread_stress_area.htm).
For our example a 1/4-20 = .031in^2 and 1/4-28 is .036in^2. So, ultimate force is 4,650 lb for 1/4-20 and 5,400 lb for 1/4-28.
UA-cam needs more 5th grade science teachers. I commend you, fellow 5th grade science teacher.
Knowing how to calculate the strength of this type of fastener reveals how much weaaker it is than the straight tensile strength would imply. This is why deaign is best left to specialists and experts.
I'm curious, where did you get the ''reveals how much weaker it is than the straight tensile strength would imply'' part? What is the tensile strength value implying? If you mean someone seeing 150,000 PSI and thinking it can hold 150,000 lbf then that would just be out of this world dumb. Unless you mean something else?
@@Orgakoyd I've definitely met people who look at the chart, see large numbers like 150,000 and immediately think a bolt can support the weight of an entire semi including loaded trailer. I've also seen people make assumptions like using the area of the head of the bolt, nominal thickness, etc. It turns out things can be more complicated and its worth consulting with someone who knows what they're talking about.
@@Orgakoyd The reveals are standard charts for engineering standards. Tensile strength represents the minimum load you can apply without the fastener breaking. If you apply any load over the Minimum Tensile Strength, there is no guarantee the fastener will not break. Theoretically, you could go up to the minimum tensile strength without the part breaking, but in normal circumstances, you would not want to. As soon as your load passes the yield point, the fastener is permanently damaged (bent - out of the elastic zone) and will never perform the same again. In Engineering, we do not design things to break or only be good for one use. We design things so the load stays down in the safe working range. We add safety factors and do our best to ensure the load never exceeds the yield point. A scene from Apolo 13 comes to mind. Watch it if you have not!. They are trying to design a way to get the stranded astronauts home. The manager asks the engineers if a device can do something. They respond, "It was not designed to do that." He responds with, "I don't care what it is designed to do (with safety factors staying away from the yield point), I want to know what it can do (one time to get the people home even if we have to go close to the yield point."
@@NCSUMESto which a good engineer would have answered something along the lines " 95 out 100 bolts will hold 200 pounds or more of additional load before yielding, while 5 out 100 will hold between 100 and 200 more. 1 out of 10'000 yielded at only 5 pounds over the limit. How lucky do you feel?"
We call 'em "farsteners" in my neck of the woods.
what the fuck.
8.8
10.9
12.9
first number x100 = tensile strength in MPa
first number x second number x 10 = yield strength in MPa
Make fasteners grade8 again! 😊
This has to be one of the most american videos ever. Not a single metric unit. Americans will do everything to avoid metric. 🦅
Cool explanation but you'd have to be an asshole to bring me the wrong bolt and not even tell me, at least get two if you get the weaker one, wtf man
So... to summarize... you just took 6:28 of our time to tell us that Grade 8 bolts are stronger than Grade 2 bolts? Do I have that right?
Because no fasteners of mine would be caught dead without having straight As as a graduate PHD Doctor Student Professor Billionaire President.
Show numbers in metric as well.
Real engineering is done in imperial units
Interesting, but can you speak English and not MERICA?
So... Weak bolts are weak? I don't feel like I really learned something here
You were supposed to learn that Grade matters. You might also have learned that bolts tend to snap at the threads. You might have learned that there is a special "area" for threaded fasteners. You might also have learned a whole bunch of basic engineering terms and concepts. Maybe watch again?
Ball of steel
That sounds about right. Keep coming back.
You'd be surprised
I think some people who watch this may learn that for a threaded joint the strength is calculated by the TENSILE STRENGTH AREA and not the cross-sectional/diametral area of the fastener.