thats what said chatgpt

Typical torque to turn a household key is roughly 40–200 in·oz (0.28–1.41 N·m) depending on lock type and condition.
For planning actuators or motors, pick a driver with 2–3× margin (e.g. a 150–600 in·oz motor for tougher locks)


so assuming 3x margin = 4.23 N-m (600 in-oz)

which sounds like a nonsense

AI is bonkers... that would shear the key with ease.

A while ago i connected socket extension to a 800W servo motor and measured torque that my hand can hold.
shaft is about 5/8" (no lever action). and since it is smooth i put some masking tape on it for better grip. as i recall, the maximum I was able to hold was about 4.5Nm and that is probably 2x what average adult may do.

i would say that turning house key should be not more than 1/10 of that. even a stiff lock is maybe 2 in-lb (about 0.25Nm). that is enough to turn the door-knobs.

or... the best approach is to just measure it yourself.

 

@panic mode assuming what u said means that 40 in-oz motor is required.

 

yes, that should be plenty to turn the key (if that is torque that can move your knob). are you sure that it needs to to turn 360deg and not only 90 or 180deg?

 

@panic mode ; that white button provided on photo has to be turned 2x , each turn is 180 deg ie 180/ or 360

 

The one in post #17 is typically 60 oz-in.

 

yes typical NEMA 17 motors should be fine. ESP32 also has numerous projects/examples using stepper. just search internet.

 

okay
what about 61 oz-in double shaft
https://anaheimautomation.com/17y302d-lw4-ms.html

Item (click for more information)	NEMA Size	Bipolar Torque (oz-in)	Bipolar Series RMS Current (A)	Bipolar Series RMS Voltage (V)	Bipolar Series Inductance Per Phase (mH)	Bipolar Series Resistance Per Phase (ohm)	Rotor Inertia (oz-in-sec2)	# of Lead Wires	Shaft	Weight (lbs)	Length (in)	Included Accessory	Lead Time	1pc Price (USD)	Add to Cart

17Y302D-LW4-MS

17

61

0.85

5.6

11

6.6

0.00096

4

Double

0.77

1.89

MiniFit Jr. Connector, Wired in Series

https://anaheimautomation.com/stepper/stepper-motors/high-torque-square-stepper-motors/17y/

 

Better price on Amazon.
Ensure it is 4-wire = bipolar.

 

Ron, mind you share a screen - i am getting Access blocked. thx

With me it is just a link to Grainger but if you just do a simple Google of "Crows Foot Wrench" you should get plenty. They look like this:




You drive it with a torque wrench.

Ron

 

Here is the spring scale version, if you don't have a torque wrench.

1. Set up the lever arm: Secure the object you are testing, such as a shaft, so that it cannot rotate. Attach your lever arm to the object.
2. Attach the spring scale: Hook the spring scale to the lever arm at a precise, measured distance from the object's center of rotation. For example, hook it exactly 1 foot away.
3. • Apply the force: Pull on the spring scale until the object just begins to rotate. Be careful to pull perpendicular to the lever arm to ensure an accurate measurement.
   • Read the force: Read the force measurement in pounds directly from the spring scale.
   • Calculate the torque: Multiply the force from the spring scale (in pounds) by the length of your lever arm (in feet).
     • Formula: Torque (lb-ft) = Force (lbs) x Lever Arm Length (ft)
     • Example: If you pulled with 50 pounds of force on a lever arm 1 foot long, the torque would be 50 lb-ft.

 

Thats what i got from nuki:

The Nuki Smart Lock works with a force of 2Nm, this is about the force an adult has turning the key with one hand. So in principle, stiff doors are no problem for the Nuki Smart Lock.
http://nuki.io/


so i am confused with the assumption:
1.41 N·m ~ 200 oz-in

 

I would measure to be exact, using either the torque wrench or spring scale method.