Drop everything, it’s this old Tony!

Hearing your boy is a preteen has given me another dozen gray hairs. Seems like yesterday he was 3 years old and "helping" build your CNC router.

I'm glad you used a Sharp calculator. Statistically, Blunt calculators cause far more injuries.

"Jars feel that same exact pain every time you close them" Tony really keeping up on that mild psychological horror. Never change.

I don't know anyone else who could make it almost 27 minute video about what's basically a fancy hinge and still manage to make it so incredibly entertaining that I was sitting on the edge of my seat waiting to see the next mechanism.

Give a raise to the mysterious guy yelling from the other side of the room, he knew all the answers 😮

I work in injection molding factory, matter of fact, making fliptop caps. I trust your story of how the bi-stable hinge was discovered. Actually, we had one cap which, if you opened it from another angle than it was intended to, the spring of the hinge snaped. One day, the mold flashed around the hinge and we discovered it made it more resistent. You could open the fliptop cap in a 45 degree angle from the front and the hinge didn't snap. That "failure" was success, and since then we made all cavities with that intentional flash. PS: I truly thank you for explaining the by-stable mechanism, specially the triangle principles. I work with these for more than 2 years and NOW I GET IT. Thank you ♥

I simply love knowing that there is a big enough community out there willing to hear a guy nerd out about over center mechanisms for almost 30 minutes. 😍

I chickened out when my kids asked about over-centre mechanisms, and I just gave them the book "Where did over-centre mechanisms come from?".

the forstner bit making the ends round is pretty funny lol

Trying to figure out how it works on your own in the shower is difficult. You're a good Dad Tony.

There is no one else on Gods green earth that could have made over-center explanation this entertaining. Well done, young man.

This is the pinnacle of KZfaq content and formatting. It will never get better than this.

26:12 "I don't know who this video is for..." Me. "...who needed to see it..." Also me. "...or what they might do with it..." Absolutely nothing, except enjoy it, obviously.

Love the video - information, insight, humor - everything. The plastic cap hinges are called “living hinges”- (I’m sure Tony will have some fun with this term.) A factoid I learned in industrial design school is that some plastic living hinges must be flexed (cycled) shortly after being injection molded in order to preserve the flex of the hinge. If this is not done, the hinge becomes brittle, reducing the number of cycles/life. This was accomplished by ejecting the part against a baffle which caused the part to close. But, this was 40 years ago, so this process might not be current. Absolutely LOVE all of Tony’s work! Thank you!

25:52 I feel personally attacked. btw Tony, I started watching your videos as a sophomore in college and I'm 3 years in the industry now. Things I learned from your videos allowed me to effectively lead my senior design project because almost all the other kids had no hands on experience. I really appreciate that you have the interest in doing this. It's probably more valuable than we all realize.

You know, watching this video made me realize that Tony probably has a side gig where he makes video's for science and shop teachers that are too hung over to teach class that day. All they have to do is take attendance, turn off the lights, play the video, and sleep until the bell.

"And now, we're well on our way to hurting ourselves." 🤣

Hard to articulate why in a KZfaq comment, but this video just made a project idea I had not only easy and possible, but it will cost me at least $1000 less. Genuinely thank you SO MUCH educated-hands-with-disembodied-voice-man.

On the opening, The dial tone automatically triggered my brain to the lyrics “I need your arms around me I need to feel your touch”

This is the absolute best over-center video I have ever seen! OK, it is the only over-center video I have seen, but it is still the best. Thanks, Tony, for another gem!

This video has changed my life and I cant explain it to anyone without sounding like a crazy person.

I was going to say "same old ToT, same quality laughs, same good content"... But no, this is on another level. This is gold! Where have you been all this time, ToT? I almost forgot how much I missed your content!!

I've dated a couple bistable mechanisms... You're a great dad keeping your kids and all the other kids in the world informed 🙌

Finally. Like the first sip of refreshing water after a long dry spell

that forstner bit gag cracked me up

I _knew_ it - ToT showers with tomato sauce! These videos are now not just machining, entertainment… they are Art! Library of Congress, you got to add these!

“To break up the monogamy..” Been there! 😂

A machinist named Tony's so neat, His videos are always a treat. When he posts something new, I can't help but woohoo! His return makes my joy quite complete!

The spring hitting the center screw actually benefits the mechanism. It makes the "sorta-stable" position in the middle virtually impossible.

The crazy thing is that I was I middle of making a TV mount for the roof of my truck and I wanted it to go up and down by itself basilly with a gas shock to assist it. I was not even looking for designs or anything like that on KZfaq when I got the notification of this video and I didn't even understand the title either just hit play because it's Tony!! Watching this has made me think of a perfect layout to build now!! Talk about perfect timming!! I am that person this video was made for!! Thanks Tony!!

Before I realized it I started clapping when that piston kept the door both open and closed. Incredible!

Excellent. If my father had this conversation with me when I was at the age of asking difficult questions, my life would have been different. Thanks Old Tony.

Just to mention the effort that videos of this quality must take to make... the wits, the attention to detail, the script... the little silly things on the side. I am always amazed.

I taught theory of machines and mechanisms and this is just perfect! It is the type of videos that get students interested in the subject. It brings the semantic gravity of it all to real-life level where they can observe these mechanisms and learn in and around their own homes. Thank you so much for the passion and effort you put into your videos!

That has to be the best explanation of something barely worthy of its own name that I have ever seen. From this day forward, I will annoy my family by pointing out every over-center mechanism I see.

Next time you watch a video of aircraft mechanics "swinging the gear" on a large airplane while it is suspended on jacks, look closely at all the struts, links, hooks and springs that come into view. You will see many over center mechanisms, and they are the devices that securely lock the gear into either the retracted or extended position. Once moved into the over center lock position, the gear will stay in that position even if hydraulic pressure is lost. If hydraulic pressure is lost in flight while the gear is retracted, simple mechanical or pneumatic devices can be actuated to move the up locks over center and allow gravity to do the job of lowering the gear and locking it down with spring-loaded over center mechanisms for a safe landing.

Looking at the light switch thinking "what's your over-center secrets" 😂

Tony if you read this, I just want to thank you so much for sharing these videos with us, they are always such a joy. The work you put into them really shines through. I’m no good with words so I can’t properly articulate my appreciation for you. You have truly mastered the art of the creative, humorous, educational video for the nerds like me who like working with their hands.

I’m native Spanish speaker and the name of this system has been eluding me for years. I once watched how this is achieved when I was first learning English but forgot the name of that particular system until today. Thank you very much.

Great to see you back 👍 I heard that it was chamfers that separate us from the animals 🙂

I didnt know they had a name, now I can talk about them properly, excellent.

I live for your videos. I don't understand the things you talk about but I learn new things every time! As a lowly HVAC guy these are amazing. The presentation and humor make every single one of these special and for that, I thank you Good Sir!

That dude who keeps answering needs to raise his hand.

Being a plastics process technician, I believe you are absolutely correct with your first theory of invention. Great video Tony, nice to have lunch with you!

You know it's going to be a great weekend when TOT posts! Don't turn that contraption upside down because all of the gravity will fall out.

How dare you teach me so much about this interesting subject? I came to be entertained, not to Learn AND be entertained!

OMG! I’m nominating you for a Noble prize. You are an extraordinary human being Tony.

Awesome timing; the other day I was watching a tow truck operator hooking up an F-150 that had dropped its differential in front of my building. When he came to install the pair of tandem trailering wheels around the immobile back wheels of the pickup, I watched him use a long rod to lever the cradle up and over centre and leave the truck locked by gravity into place four inches above the ground and I was struck by just how utterly brilliant yet gloriously simple that invention was. And now here you are, teaching me all about the concept in yet another amazingly well scripted, filmed, edited and executed video. This is exactly the kind of stuff for which KZfaq was invented!

26 minutes and I'm still glued to this concept - I'm a maple producer, I make maple syrup in a saphouse in my backyard - and the windows in the cupola up on the roof have to be opened and closed when in use - they are 14ft off the ground, and it took a bit of figuring, but I was able to use an over center mechanism to help them start to move from vertical to nearly horizontal. Great video!

I feel educated. As a non engineer, this video taught me a lot and covered different ways this technique is applied. I can't thank you enough for making content this precious. You're amazing, keep up the good work!

The plastic hinges are called living hinges and fall under the discipline of compliant mechanisms. You have to use some funky calculus (elliptic integrals) to analyze and design them. Very cool stuff.

The Forstner bit gag at the beginning is easily missed but brilliant. I wish making an external radius was that simple. 😊

I mean this with all my heart and soul. My eyes light up like its chirstmas when i see a new video uploaded. Your sense of humor super smartness is one of a kind. I would love to meet you one day. Just to sit down and talk shop. Thank you for everything. Tony, you are seriously my hero.

It just occurred to me that I haven’t experienced this same cocktail of wonder/awe/laughter since watching James Burke’s Connections series on PBS back in 1978. Thank you, I’ve been missing it

Dude you are my kind of crazy. So many people just accept such everyday little engineering marvels and never stop to appreciate any of it. Loved this video.

7:28 a Welsh man once told me a sheep is like a spring. I never did get this, but now I know. Thank you 😆

These educational videos are 10/10. Even if it's a concept you already know, you always pick up something new. 10/10, LOVE THESE.

This video had the perfect blend of Humor, education and randomness. Thanks Old Tony :)

The jab at Olive Garden....priceless!

I like that subtle throw back to the goof who suggested the chuck could be locked by unlocking it.

For the last 63 years I never thought of 'over center ' now thanks to you I see it every where THANKS tot!

"if you made this far" bro, you are the only content I can watch for 2 hours

Damn man, I don't think you realize how amazing your videos are. Your skills in mechanics, humor, storytelling, videomaking and all other stuff that goes into these videos are AMAZING.

I'm so thrilled about that upcoming video about poop jar!

I waited months for a new TOT video, and you never disappoint when it happens! Thank you for the great laughs! 😂

how funny, i was getting online to look up hinges and latches for a box im making my daughter. She asked me to build a box for her tattoo equipment with a false bottom so she can hide things in it. now im gona use a gass cylinder to hold it open and closed. thank you Tony. saved me lots of time.

As a truck driver; my favorite over-center-mechanism is a lever action chain binder. Outlawed in a few states due to how much force it can pack, but sure can make a chain tight in seconds with some mechanical advantage help from a cheater bar!

Really holds your attention, keeps you locked in

The poop jar bit made me actually laugh out loud 😅😅

I wasn't getting worried. I knew This Old Tony would come through after a well deserved rest. I needed to see this.

I can’t believe there was so much here that I didn’t even know that I didn’t need to know, but I am definitely a better person now that I do.

How can 26 minutes go by so quickly? Entertained, educated and greatly amused, it's a true wonderment for which I humbly thank you.

This video was for me! Just today I modified my drill press table by drilling a hole through it in the upper left hand corner, to accept a Harbor Frieght Pittsburg brand table clampy vise grip thingy. It's the benchtop 12 speed press, also from HF, so it's table is too small to use the slots in it for anything other than a fence, which I made out of some angle iron and a couple of stainless carriage bolts. I make knives, so this makes things easier that using the deep throat clamp I've been using for years.

I've had my fair share of education. You are one of the best teachers I've had. Thanks TOT!

I've been watching these videos for so long, that I've gone from being mystified and excited about concepts, to intuiting mechanics naturally, to being able to calculate them in linear algebra. I don't just see the mechanism anymore, I see state vectors of material strengths, stress graphs, dynamic free body force diagrams. When I see mechanisms like this I think about how I want to implement them as trajectoid rolling cam capstan tension joints, milled on compound differential machines, blah blah blah. I naturally jump to calculus solutions even when algebra is sufficient. I'm working on moving back towards simplicity, I want to find the gauge symmetry solution to every problem I encounter, instead of the convoluted, eclectic, un-implementable nonsense I come up with at first blush. Wherever I end up in the future, I just wanted to say you've been a major part of my journey. Textbooks seem to put absolutely no effort into motivating the problem solving processes. So in my opinion, these videos are uniquely valuable. I am deeply grateful for the incredible amount of effort it must have taken to make them over these long years.

I'm honored to hear that you place our edification above and beyond your children's. Thank you.

I really wish this had been out a few months ago. I was making what I now realize is an over-center hinge, but didn't know that's what it was called. It made looking for resources so much harder.

Just simply brilliant. Thanks Tony.

The only maker that makes me stop whatever I’m doing and watch as soon as I see the notification. It’s like a surprise present from a friend! Keep it up Tony!

I knew a guy called TOT . Used to make some pretty good KZfaq videos ... not seen him for a while now but they say , on cold dark nights when the wind blows from the west , you can still hear the faint sounds of informative light hearted educational videos wafting through the trees .. :)

Things we use everyday, explained, miraculously! Thanks TOT!

I didn't realize how much I needed a This Old Tony video until I started it, it just makes me happy! And kudos for giving flip top lids the admiration they deserve, live hinges have their own set of challeges to design. 🙂

Nothing better than laughing while learning something new. Thanks.

The "The engineering guy" orientation mixed with your style is fantastic. How a simple common mechanism works explained in a very very simple way. Fantastic.

Thank you. Sometimes I wake up at around 5AM and I can't get back to sleep. You and Mustie are my go-tos to get back to sleep.

Thank you for your service.

Aircraft landing gear rely on "over-center" mechanisms to "lock" down and into place. Yet another amazing application of this mechanical concept.

Thanks This old Tony. Putting screaming arthritic jars in my next D&D session. You never let me down.

“AS ALWAYS”……❤ enjoyed, great discussion on a design which we use daily on countless items

Thanks for the video This Old Tony! Absolutely magical!

Thanks TOT, your clear explanation of over centre locking systems has allowed me to undo the nipple clamps I’ve had stuck to me for the last 3 days. Phew!

Good job you put that 'un-pause now' hint in there otherwise I'd still be sat here staring.... what am I talking about, we're only a quarter of the way in so I'm still staring. 🤣

this is a very flippin timely video! This video was for me! I needed to add a gas spring to an industrial enclosure design, but for some reason was only considering compression gas springs, not extension ones! Thanks Old Tony!

Over center is really important in retractable aircraft landing gear. This helped me solidify the concept. Thanks!

It was just yesterday I was thinking, man I miss a good ToT video, my prayers have been answered.

And there I was thinking that TOT had snapped over his personal center... Thanks for coming back with such silky smooth content and hair.

As I was watching this, I was fidgeting with the die-cast model Shelby Cobra my kid gave me last Father's day and realized the doors use over-center mechanisms to snap open/closed. Thanks Old Tony!

I just started a job as a CNC machinist for an injection mold manufacturing company. This video was definitely for me. Thanks @This Old Tony

Can we just applaud this mans editing skills for a couple seconds????