Want to get yourself frustrated? Just try to teach someone proper screw tightness!

[rosewood]

Too many people use power tools to install sheet metal screws because it saves time, and in their haste they over-torque and auger out the heads/sockets.
I worked in the aviation maintenance industry for many years, and dealt with those same problems on a regular basis.
With aircraft, probably 90% of threaded fasteners have a torque value listed in maintenance manuals to be adhered to and documented.
Absent any guidance on how tight to install a bolt or screw, the proper method is to tighten 1/6 to 1/3 of a turn past a significant increase in felt resistance (torque). I use this method on lawnmower blade bolts, rifle scope ring and mount screws, wheel lug nuts, etc.
Anyone should be able to understand that, and with repetition becomes second nature requiring little thought.
I should mention that one of my top pet peeves (right up there with people that chew their food with their mouth open) is over-tightened screws, bolts, AND TIRE LUG NUTS.
More people having torque wrenches would only partially lessen the problem at hand unless the person has ready access to fastener torque value charts or manufacturer’s guidelines, which most don’t have and won’t try to find anyway.

How about oil filters too!

 

[Autonomous]

Random thoughts.

Someone smarter than me recommended Vibra-Tite VC-3 reusable threadlocker for firearms.

When using oil-grease-anti-seize on fasteners you need to decrease torque by a significant amount to prevent stretching them. Just because you have gotten away with not adjusting the torque value before does not mean you can't start using best practice going forward.

Lubricated Bolts and Reduced Torque

Lubrication effect on bolt tension and torque.

www.engineeringtoolbox.com

Back in the day before anyone had heard of Japanese Industry Standard (JIS) screws, everyone used Phillips screwdrivers on them and stripped the heads out. This required the use of a handheld impact tool to proceed.

 

[Jimbo41]

Some years back I bought a Wiha variable torque screwdriver. It really helped me calibrate my arm for mounting optics and the like.

 

[chief38]

Too many people use power tools to install sheet metal screws because it saves time, and in their haste they over-torque and auger out the heads/sockets.
I worked in the aviation maintenance industry for many years, and dealt with those same problems on a regular basis.
With aircraft, probably 90% of threaded fasteners have a torque value listed in maintenance manuals to be adhered to and documented.
Absent any guidance on how tight to install a bolt or screw, the proper method is to tighten 1/6 to 1/3 of a turn past a significant increase in felt resistance (torque). I use this method on lawnmower blade bolts, rifle scope ring and mount screws, wheel lug nuts, etc.
Anyone should be able to understand that, and with repetition becomes second nature requiring little thought.
I should mention that one of my top pet peeves (right up there with people that chew their food with their mouth open) is over-tightened screws, bolts, AND TIRE LUG NUTS.
More people having torque wrenches would only partially lessen the problem at hand unless the person has ready access to fastener torque value charts or manufacturer’s guidelines, which most don’t have and won’t try to find anyway.

ESPECIALLY when it comes to sheet metal! It is extremely rare I work on something that is made of sheet metal (like an AC unit) that has been worked on by others and doesn't have a bunch of stripped screws! Whenever going to someones home to service an AC unit, I always bring extra and larger sheet metal screws to replace the stripped ones. Pretty sad actually!

 

[JimFr]

Now let’s talk about those that use the common 1” micrometer as a “C”-clamp!

 

[MyTurn]

Random thoughts.

Someone smarter than me recommended Vibra-Tite VC-3 reusable threadlocker for firearms.

When using oil-grease-anti-seize on fasteners you need to decrease torque by a significant amount to prevent stretching them. Just because you have gotten away with not adjusting the torque value before does not mean you can't start using best practice going forward.

Lubricated Bolts and Reduced Torque

Lubrication effect on bolt tension and torque.

www.engineeringtoolbox.com

Back in the day before anyone had heard of Japanese Industry Standard (JIS) screws, everyone used Phillips screwdrivers on them and stripped the heads out. This required the use of a handheld impact tool to proceed.

Real world question, then. What should the torque be for an AR-15 barrel nut when using the grease recommended in the military manual?

 

[roundels]

Too many people use power tools to install sheet metal screws because it saves time, and in their haste they over-torque and auger out the heads/sockets.
I worked in the aviation maintenance industry for many years, and dealt with those same problems on a regular basis.
With aircraft, probably 90% of threaded fasteners have a torque value listed in maintenance manuals to be adhered to and documented.
Absent any guidance on how tight to install a bolt or screw, the proper method is to tighten 1/6 to 1/3 of a turn past a significant increase in felt resistance (torque). I use this method on lawnmower blade bolts, rifle scope ring and mount screws, wheel lug nuts, etc.
Anyone should be able to understand that, and with repetition becomes second nature requiring little thought.
I should mention that one of my top pet peeves (right up there with people that chew their food with their mouth open) is over-tightened screws, bolts, AND TIRE LUG NUTS.
More people having torque wrenches would only partially lessen the problem at hand unless the person has ready access to fastener torque value charts or manufacturer’s guidelines, which most don’t have and won’t try to find anyway.

Yep yep. When I was doing automotive work I used to use the knob end on Craftsman screwdrivers to guesstimate torque on easily stripped or broken fasteners. Nestling the knob in the web and thumb/forefinger of my hand and tightening as much as my grip would allow gave perfect results.

 

[roundels]

Real world question, then. What should the torque be for an AR-15 barrel nut when using the grease recommended in the military manual?

35-85 ft. lbs. Aeroshell 33 is the customary grease. Make sure you use a high quality wrench with nubbies all the way around to completely grip the nut and a clamshell with a gas tube pilot rod-equipped receiver insert rather than the all in one that just goes off the receiver tabs. Don't skimp on paying for either of these unless you want to do the whole thing over and possibly ruin the parts as you go.

Also, the bigger the vise (at least 5") and the heavier the bench it's bolted to (no plastic event tables) the better your results will be. Any flex in either will affect torque specs. It's a good idea to cover the upper with 2 layers of masking tape before you start to keep the finish from being glossied up by being pressed hard against the inside of the clamshell, which will need to be clamped on fairly tightly. Torque and release the barrel nut three times to help mate the threads and then set final torque unless the nut lines up the first or second time at at least 35. If you are right at the high end spec and the gas tube still isn't lining up after mutiple attempts at torquing and releasing try a different nut. You'll have to take everything apart if you need to do this so you might want to start with a bare barrel just in case. Don't overtorque and whatever you do don't break out the files. Shims can also be used but as a last resort.

 

[Tiger 11]

Too many people use power tools to install sheet metal screws because it saves time, and in their haste they over-torque and auger out the heads/sockets.
I worked in the aviation maintenance industry for many years, and dealt with those same problems on a regular basis.
With aircraft, probably 90% of threaded fasteners have a torque value listed in maintenance manuals to be adhered to and documented.
Absent any guidance on how tight to install a bolt or screw, the proper method is to tighten 1/6 to 1/3 of a turn past a significant increase in felt resistance (torque). I use this method on lawnmower blade bolts, rifle scope ring and mount screws, wheel lug nuts, etc.
Anyone should be able to understand that, and with repetition becomes second nature requiring little thought.
I should mention that one of my top pet peeves (right up there with people that chew their food with their mouth open) is over-tightened screws, bolts, AND TIRE LUG NUTS.
More people having torque wrenches would only partially lessen the problem at hand unless the person has ready access to fastener torque value charts or manufacturer’s guidelines, which most don’t have and won’t try to find anyway.

What has always been my method is to use the power tool until just before the screwhead contacts the metal - then finish up by hand, with or without a torque wrench.

 

[Doriangray6]

When I taught the V-Rod course at MMI there were always students that thought they had calibrated hands and didn't need to use torque wrenches so I'd have them tighten a fastener that required 100 to 120 inch pounds of torque to what they thought was the correct torque with a regular wrench and then use my dial face inch pound torque wrench to loosen it.
Their calibrated hands always tightened the fastener to at least twice the correct torque amount.