So, as a maintenance QC Inspector for a U.S. Major Airline of 24 yrs, one of our jobs in QC is to re-calibrate and certify all of the Torque Wrenches issued to the mechanics, for work on our Aircraft, by our Tool room. Proper Torquing IS a big deal, is Required to be done In Accordance With the manufacturer's specs and is Required to be witnessed by a QC Inspector, for a specified group of maintenance items called out by the FAA. All U.S. Carriers use this same list of Required Inspection Items (the RII list). This is a good subject to know a bit about, especially when working on such specialized hardware and equipment as Bicycle's have become. That said, some items are too delicate to put a Torque Wrench to, as damage will occur. You did well here in explaining & warning of the problems & issues caused by Over-Torquing & Under-Torquing as well as the mechanics behind how Torque Wrenches work, BUT, you never explained what Torquing a screw actually does. Torquing a screw essentially has the same effect as adding a Locking Washer under the head of the screw, or adding Loctite to the screw threads with metal-on-metal screws. Torquing a screw actually Stretches the screw within a fixed thread pitch which causes physical binding between the screw & the base metal threads or nut. This serves to lock the screw in place. Torquing screws is simply a method of binding screws to their threaded base metal or nut. That said, there is a narrow limit to stretching a screw before it reaches its "elastic limit". Often the base material is too soft or not strong enough to allow a screw to stretch (be torqued). Just something to be aware of, more Torque isn't better. Torquing a hardened steel screw into soft aluminum, plastic or some composite material will usually damage the threads of the base material. Only Torque what is called for, meaning you're dependent on your calibrated elbow for the softer materials. For what it's worth, Beam type Torque Wrenches are almost Always the most accurate, because of their simplicity. That's followed by "click" types which are easily damaged if used to loosen stuck or over-torqued screws. Torque Wrenches should never be used as a substitute for a Ratchet Wrench or simple wrench, that's what usually causes the calibration to change. Since Torque requirements for bicycles tend to be on the "low" side, you're far better off w/ a "fine" ratchet on your Click type Torque Wrench vs a coarse rachet. Usually the cheaper Click type torque Wrenches will be a fairly coarse type ratchet, so look for that. The finer the Ratchet on a Click type, the easier to work in a tight spot. The "slip" type of Torque Wrenches are the least accurate, so get a good name brand if you can, it'll be the most accurate. In the aviation world, it's sometimes required to measure the "running Torque" of a bolt or screw, iow, the amount of resistance or friction on the bolt shank before it's begun to tighten. You add the running torque to the specified finish Torque setting for an accurate actual Torque. So, if a screw or bolt has a lot of resistance while rotating before it's reached its tightening phase, it's possible to under-torque that screw if you go the min Torque setting.

This one is a keeper! Best top level overview of common fasteners and proper torque tools ever and I am going to refer a lot of people to it. This was also the best woken and visual explanation of each of the most common tools a bike mechanic will encounter. Your discussion on proper storage of each type was essential and something very rarely addressed. A good follow on would be to cover electronic strain gauge based torque sensors and their benefits, but that is a bit OCD for bike wrenching. A deeper dive into the topic of how it is the “load path” and initial installation conditions that determine the optimum torque, not solely the bolt. It is the stress distribution of the load path that torque is being used as a proxy. This proxy assumes that all elements in the load path meet their relevant material specifications, correct initial conditions the proxy was based on, and that tool and technique are valid. Miss one of these (and maybe some I overlooked) and the connection is no longer fit for purpose.

Loved the explanation of how each wrench type works inside.

I always learn from this channel, thanks!

That was very informative, thank you. I want PT-ATD now :)

Excellent !

Fixed torque keys are my favorite. I use my 5nm, and 6nm torque keys constantly building bikes, and doing service. I use my Park click type wrenches for higher torque values.

Great video. :) My thinking out loud: Fact 1: No shop in my city has a torque wrench as far as I know (except one, where I gave them that as a gift for opening - LOL). Fact 2: I've worked for decades without a torque wrench. And still I would not recommend working without one, especially on modern light stuff (not to mention carbon) - and definitely not as a pro mechanic (liability risks in case of any problems). Relja

Loved the history lesson, did not know about the robertson in the model T getting a jump start. Phillips(not jis) is designed to strip the head before breaking the bolt or parent material.

And today we're gonna torque about.... On a serious note I got my torque wrenches hanging right next to my hex and torx tools right behind my bike stand. There's no point for me NOT to use it. However, I did make an exception recently when I was going to remove tokens from my Fox fork and nobody in my country had a 32mm chamferless 3/8" socket which is why I opted for a 32mm chamferless 1/2" instead and just use a normal ratchet wrench for dismount and mounting. Some workshops told me they never used a torque wrench for it, so I thought to myself that it's probably fine. Just snug it up and no heavy force, and if there's no airleak then it should be golden.

I so enjoy your wonderful videos. It's amazing that you have the ability to take the boring subject of torque and make it interesting and informative. BTW, I have a few acquaintances who volunteer at the Sacramento Bike Kitchen. Is there a backstory on how you came upon Bike Kitchen t-shirt?

Love the channel and all the great bike shop business content! Unfortunately, you absolutely can over-torque bolts with those slip-type torque wrenches. When they click, they apply an instantaneous force similar to how the hammer of an impact wrench works. Clicking it once is a non-issue, but continuing to click them will over-torque a bolt really fast.

Wera does have click type torque wrenches that you cannot overtighten; safe-torque they call them.

Great tutorial and overview. You reminded me of something that I've long wondered, which is why click torque wrenches specify storage at the minimum setting, not zero. My guess is that dialing it to zero could leave space between the parts, allowing corrosion to form more easily than if they were actually in contact. Do you, or any viewers here, know if that's it?

I appreciate the brief history lesson about bolt types and how they came to be, but you somehow failed to mention the also common hex head.

I'm too chicken to trust myself that the click type would be calibrated correctly when I go to use it, so I bought both of the Park Tool beam type. Pretty foolproof, even for this fool.

I enjoy the info. But hate your movie skits. !