| DonkeyHody 2005-12-30, 11:21 am |
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KMoiarty wrote:
>
> Further to my inquiry below, does anyone happen to know how a typical corded
> driver would rate if actual torque specifications were provided for corded
> drivers like they are for cordless? For example, roughly how many
> inch-pounds of maximum torque from, say, my 4.6 amp (Skil "Slugger", geared
> to rev up to 2600 rpm) corded drill?
>
Ken,
I wish it were that easy. I can tell you that 4.6 amps at 120 volts
translates to 18 inch pounds of theoretical torque at 2600 rpm. BUT
(you knew there would be a but, didn't you?) that doesn't consider
friction losses in the gear box which will eat a lot of that torque.
And it doesn't consider that the motor will slow down when a load is
applied, and will generate more torque at lower speeds. Just how much
torque it can develop is determined by the torque curve of that
particular motor. That particular drill probably won't develop as much
ultimate torque as a good cordless.
Torque alone is not a good indicator of performance because it ignores
speed. If you grab the chuck, the cordless seems stronger, especially
in low gear. But when put to the task of drilling, your "Slugger" is
whizzing around at close to 2600 rpm, while the cordless is chugging
along at under 1400, even in high gear.
Consumers are left without reliable ways to compare one cordless to
another, much less cordless to corded. Check out the Consumer Reports
article where they found some higher-voltage drills didn't develop as
much power as other lower-voltage ones. That's why I said ignore the
specs and buy what feels good in your hand. The major brands all put
out enough power for most of our uses. When that's not enough, grab
your extension cord.
But you are right that cordless cannot develop as much power as even a
medium duty corded drill.
By the way, a 4.6 amp 2600 rpm B&D wasn't exactly what I had in mind
when I suggested a corded drill for those times when your cordless
couldn't get the job done. I was thinking more along the lines of this
7.8 amp Dewalt geared to turn 850 rpm.
http://www.amazon.com/gp/product/B0...29617?n=228013.
You won't have any trouble knowing whether that one is stronger than a
cordless.
DonkeyHody
"Every man is my superior in that I can learn from him."
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