# 300 UWO (Unit Watts Out) equals more or less than 300 in-lbs?



## justplumducky

My current cordless drill torque rating is 300 in-lbs. Lost one of the batteries and the remaining one expired. Wouldn't charge on the charger any more. 

Looking at Dewalt's 20v, model number DCD771C2 cordless kit (1/2" chuck, two batteries and charger), which has a power rating of 300 UWO (unit watts out). Can anyone tell me the approximately equivalent in in-lbs of torque? 

Is 300 UWO at least higher torque than my original cordless with 300 in-lbs

http://www.homedepot.com/p/DEWALT-2...-Cordless-Drill-Driver-Kit-DCD771C2/204279858


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## thediyhubby

Lately Dewalt only supply the UWO and not the torque, while some other manufacturers again only supply the torque rating. Here is a comparison chart of some cordless drills with torque ratings and power output ratings.
_link removed_


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## Daniel Holzman

This is an interesting example of improper comparison of units, due to faulty physics. An inch-lb, like a foot-lb, is a unit of energy, not a unit of power. A watt is a unit of power, not a unit of energy. In the automotive world, the typical power rating for a car is in horsepower, which is 550 ft-lbs/sec, and the typical unit of torque is in ft-lbs, so torque is a unit of energy.

Just as you cannot directly compare a truck that generates 500 ft-lbs of torque to a hot rod that generates 500 horsepower, you cannot directly compare a drill with a rating of in-lbs to a drill with a rating of watts. You can convert the two units, but you have to know the rpm's of the tool at the comparison point.


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## justplumducky

Daniel Holzman said:


> This is an interesting example of improper comparison of units, due to faulty physics. An inch-lb, like a foot-lb, is a unit of energy, not a unit of power. A watt is a unit of power, not a unit of energy. In the automotive world, the typical power rating for a car is in horsepower, which is 550 ft-lbs/sec, and the typical unit of torque is in ft-lbs, so torque is a unit of energy.
> 
> Just as you cannot directly compare a truck that generates 500 ft-lbs of torque to a hot rod that generates 500 horsepower, you cannot directly compare a drill with a rating of in-lbs to a drill with a rating of watts. You can convert the two units, but you have to know the rpm's of the tool at the comparison point.


I'm not sure if you're labeling my question as an improper comparison, or labeling the article information as such. However, that's what my link (the article) is all about... detailed information to facilitate arriving at a more accurate comparison of those cordless drill/drivers in the article (only those tools listed in the article, no other types of tools). Uh oh - forgot that I started another thread for the articlel/link I'm talking about, so here's that link:

http://www.protoolreviews.com/tools/...round-up/5108/ 

If you were labeling my question as an improper comparison (well, you couldn't have been labeling the article -- the above link -- because I hadn't yet posted it in this thread), I understand and could have been more thorough in stating my question. 

However, I was hoping that someone with prior experience comparing UWO with Torque (cordless drill/drivers) could shoot from the hip and tell me if the cordless I was considering (300 UWO) was at least higher in Torque, so I wouldn't be buying a less "powerful" cordless for driving screws at a comparable driving speed. I've quoted powerful because as the article states, it can mean different things, depending on what kind of performance you're after from the cordless in question.

I believe the author of the linked article concedes that his method of comparison is not perfect, but reasonably close. Possibly you can confirm that, or improve on it? Thanks for jumping in...


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