How are we measuring torque these days?

[Tom the Remodeler]

Hi again everybody! So I'm about to take the plunge into a C12, and in my research I noticed some huge discrepancies between the different drill/drivers on the market in regard to their rated torque. For years it seemed like torque was rated in inch-lbs, and most professional 18volt drills seemed to hover around 500 in-lbs. Now, my understanding is those measurements can be pretty misleading because there was no industry standard method (in NA) for measuring torque.  However, I remember a blurb in a trade magazine a few months ago about a new industry standard agreed to by all of the major tool makers so it'd be easier to compare models. So, now I'm looking at my 2008 Hilti catalog, and it states that they are using a European standard that provides two torque measurements: "hard joint" and "soft joint". Apparently "soft joint" torque is most applicable to construction, and nearly all of the Hilti drills, from 14.4v to 15.6v to 18v all rate at 292in-lbs, with the 24v rated at 398 in-lbs and the 12v at 186 in-lbs (all in wood). This makes a little more sense to me that the C12 would be rated at 265 in-lbs in steel and 160 in-lbs in wood. However, now I go to the Dewalt website and see they are now measuring in "Unit Watts Out"? What gives? Does anybody know what the future, standardized unit of measure for torque is going to be? Thanks!!

 

[Frank-Jan]

Hmm, I always thought the standard unit for torque was Nm, (Newton meter) Just did some searching, and this is the standard unit for the SI system.
Wiki-link Another wiki-link

some quotes:

"1 newton metre = 0.7375621 foot-pound force (often "foot-pound") "

"Three nations have not officially adopted the International System of Units as their primary or sole system of measurement: Liberia, Myanmar and the United States."

I was looking at the hard/soft numbers etc myself a while back, after I got my 18v Protool hammerdrill.

I really wanted a new cordless drill, but couldn't choose (14.4 V panasonic, or makita (of which I have the impact driver, and an extra battery, but I read bad stuff bout the gears of the regular drills, and one of the chargers we have made the dreaded sound). So I decided to hold off untill the 12V dewalt I had died (I had a XRP which held up very well, but it died recently, and I used the cheap dewalt drill I got when I needed new batteries (that drill + charger + 2XR2 batteries was cheaper than just the batteries). But when they had the protool drill on display, I couldn't resist temptation, and just got it...

I've had it for 2 weeks now, and really like it. Centrotec; right-angle head; 4 speed, with a whopping 3800rpm max; tec motor like the C12, including the beeping electronic clutch thingy,...
Torque is 40Nm soft/ 60NM hard.
It's a bit overkill/ too bulky for the fine woodworking most people here do, but it fits my needs very well. I'll post some pictures when the centrotec stuff arrives I ordered (should be in this week)

 

[Tom the Remodeler]

Hi Frank-Jan! Yeah, I noticed that all of the Euro websites list their tools in NM, but I am also wondering how they get their results? Are they using a standardized test, or is all of the testing done to in-house standards? Definitely post some pics once you get the Protool! I was chatting with a Fes rep the other day and he said there was talk of bringing Protool to NA, so it'd be neat to get a sneak peak!  ;D

 

[Frank-Jan]

I guess it's done to inhouse standards, this video shows how festool tests their new li-ion drills: link The test is at 2:45 in the video.

I have the protool drill for 2 weeks now, but I'm still waiting on the centrotec stuff. Sofar I used it for drilling lots of small diameter holes in steel, some screwdriving (still prefer my makita impact for that, but my dad preferred the protool for screwing through the steel (he snapped a few screwheads with the impact, after that he liked the electronic clutch thing), and used it with 83 and 75 mm holesaws through OSB and ply. I haven't taken any pictures yet, but here is a video that has been posted a few times already.

 

[Brad Evans]

I hope it's not how the big-name shop vacuums measure horsepower...

 

[jaegerhund]

Well if you are not too rigorous with concepts here,  a Nm is a joule and if they measure it over a time span, they can get watts --- just playing around with units.

Justin

 

[extiger]

Having just purchased a C-12 Drill, I wondered how powerful it was. So I contacted Milwaukee about their corded Magnum 1/2 drill that I used so much in construction. Their website didn't have torque ratings.

They answered yesterday that it develops 230 inch-pounds of torque. I am assuming it is inch-pounds because I asked for that number. Foot-pounds would be absurd. Although the Milwaukee is sort of frightening in its capabilities.

So that means (if I am absorbing this correctly) that the 3-phase AC motor in the C12 is equal to a corded 1/2 " drill. And I don't get the part about dual ratings for steel and wood.

Gary Curtis

 

[Ron Pegram]

Having just purchased a C-12 Drill, I wondered how powerful it was. So I contacted Milwaukee about their corded Magnum 1/2 drill that I used so much in construction. Their website didn't have torque ratings.

They answered yesterday that it develops 230 inch-pounds of torque. I am assuming it is inch-pounds because I asked for that number. Foot-pounds would be absurd. Although the Milwaukee is sort of frightening in its capabilities.

So that means (if I am absorbing this correctly) that the 3-phase AC motor in the C12 is equal to a corded 1/2 " drill. And I don't get the part about dual ratings for steel and wood.

Gary Curtis

My guess would be inch-pounds as that's how screw torsional strength is measured.

This is a link to a graphic displaying our screws' typical torsional strength by head size:

McFeely's Torsional Strength Chart

 

[Tom the Remodeler]

Ok, here's  the article I was thinking of.

 

[Tom the Remodeler]

And THIS is another great explanation, it even gives some examples comparing Milwaukee, Dewalt, Bosch, and Makita drills. No C12 though..... Very interesting nonetheless!  8)

 

[extiger]

Great information, Tom. I'm tempted (like everyone) to think about Torque in automotive and truck engines. Diesels have a huge amount of torque and and thus can drag a bank safe up a steep hill. Starting with the info on my Milwaukee half-inch corded drill, I know that when running an auger bit through 2x4's the torque meant it would rip my arms off if the bit jammed or stalled.

So when Festool rates the C12 at the same number of inch/lbs -- 230 in this case -- it tells me that I can drive almost any size bit through tough material. I don't do construction work, so this doesn't offer great appeal. But I would think a guy driving those long deck screws all day long would make a purchase choice based on those numbers. In the several technical articles on the C12 offered by Festool, practical considerations are almost drowned out by tech data. 4 paragraphs on the planetary gearing. Yawn. And I come from an aviation background. I simply wanted to know what an brushless, 2-phase AC motor offer in real-world terms.

Gary