On relation to ratchet length, how much torque can one get?

[robertsolson]

I was told once that with a 9 inch ratchet, you can get about 35 pounds of torque. And I have read that you can get 1000 pounds of torque from a 40 inch breaker bar. Is there an equation to estimate the relative torque for a length of ratchet?

 

[Givl Reggin]

Pushing or pulling? Constant pressure with a smooth motion or jerking? Lots of factors... I don't know if it would be possible to come up with a rule-of-thumb.

 

[SMKS]

Well, you'd have to exert around 300 lbs of force on a 40" bar to equal 1000 ft lbs (if my math is correct). That's possible, but it would be pretty difficult to do.

 

[gtrotter]

Well, you'd have to exert around 300 lbs of force on a 40" bar to equal 1000 ft lbs (if my math is correct). That's possible, but it would be pretty difficult to do.

Not that hard, just stand on it?

 

[chris142]

I'm pretty sure that I can supply more than 35 pounds of torque to a 9 inch ratchet. 35 foot pounds aint nuthen.

 

[blacK20]

I don't understand what you're trying to ask. The amount of torque you can get is all relative to how hard you can push/pull on that ratchet. (up until something on the tool breaks of course). As well as the length of the ratchet.

 

[alvoski]

Lenght of ratchet in feet X force applied = torque

Or

(length in inches) /12 inches X force applied = torque

Anyone please correct me if I'm wrong. I haven't done algebra in a few years

 

[shampoop]

it's all about how strong you are + how long the lever is + how much power is stolen by the tool flexing.

you can definitely exert a lot more than 35 ft/lbs with a 9" ratchet.

 

[SMKS]

Not that hard, just stand on it?

I don't know how much you weigh, but I weigh 190 lbs. Standing on it would not equal 300 lbs. I'd have to be jumping on it, while attempting to keep the bar in place.

 

[Olafur]

I was told once that with a 9 inch ratchet, you can get about 35 pounds of torque. And I have read that you can get 1000 pounds of torque from a 40 inch breaker bar. Is there an equation to estimate the relative torque for a length of ratchet?

Yes, and a simple one.

Torque = "length of the ratchet" multiplied by the force applied.

Length of the ratchet - meaning the distance from the center of the square drive to the "point" where center of the force applied (i.e mid handle).

It follows, for the same force; if you double the length of the lever (ratchet, breaker bar) you double the torque.