I am trying to figure out how much sustained torque my old style Hole Hawg is capable of.
For what its worth I see some cordless drills rated at 33 ft-lbs (400 inch pounds) but that must be when the windings ignite or the battery ruptures. Surely a cordless is only capable of say 5 ft-lbs in a sustained fashion.
Hawgs can toss you when they bind but that is more of an instantaneous torque resulting from the gearing and motor inertia (think flywheel). What I am interested in is sustained torque.
If you have any ideas please let me know.
John
Replies
I'm clueless, even less clueless as to how you would measure sustained torque with anything you might have on hand.
Maybe go to Milwaukee's web site and click on "contact us"?
Jim
I'm clueless, even less clueless as to how you would measure sustained torque
Sustained torque is measured with your hand pinned between hole hawg & immovable object.
Might sometimes also be measured by blood loss.
Joe H
Agreed, but I think he wants a quantitative number perhaps for comparison.
Might also be RPM of your body spinning around the drill motor.
Ever notice how long it takes to convince your body to let go of the trigger when that happens????
JimNever underestimate the value of a sharp pencil or good light.
Joe,
Sustained torque is measured with your hand pinned between hole hawg & immovable object.
Its only "sustained" if your trigger finger is pinned with the switch in the ON position.
Jim x 3
I'd somehow chuck a piece of pipe to the Hawg, then build a "brake" on the pipe with a couple of pieces of wood and thumbscrews (or maybe something a little beefier). Set up the Hawg in a test fixture with the shaft up, the lever arm of the brake off to one side. Attach a rope to it with a pulley so you can hang weights on the rope. Rig a disconnect switch so that if the lever arm swings around the power will be cut.Start the hawg and slowly tighten the brake (make sure the nut you tighten is on the "safe" side of the lever arm) until a known weight is (barely) lifted. The length of the arm times the weight gives you the torque being generated.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Understood how to measure momentary torque, your technique would certainly work.
But, he asked originally about measuring sustained torque.
I interpreted sustained torque as a "duty cycle" of sorts, like perhaps he was trying to run a pump or similar with the Hole Hawg motor.
Or perhaps as a comparison value against another tool.
JimNever underestimate the value of a sharp pencil or good light.
No, my scheme would measure sustained torque. Of course, it's up to the tester to decide whether a given load is "sustained" or sufficient to burn out the motor.(I'd modify my scheme slightly to add a second weight, below the first and separated by an inch or two of rope. Tighten until the first weight is lifted. The second weight is "insurance" to keep the arm from swinging around.)
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Got it, you would leave the drill motor running after the lift = sustained torque.
I guess you could monitor the motor exhaust temperature to decide when to shut it off......
JimNever underestimate the value of a sharp pencil or good light.
The easiest way to measure torque might be to chuck up a drum with a rope wrapped around it, put a weight at the end of the rope, and see how much weight you can add and have the drill still lift it at a constant speed.
A big drum (longer torque arm) will reduce the amount of weight you have to use.
Or, clamp the chuck in a vise, attach a really big fish scale to the handle, lock the trigger down, hold the other end of the fish scale, and plug her in!
Forrest
I've tried to measure foot pounds before and with the weight on a rope it doesn't transfer over. Well, not for me.
A foot pound is a pound of weight at the end of a one foot lever sticking out level with the floor.
It's the same with newton meters. Not sure what a newton is but I know what a meter is. So your lever is a meter.
I had to measure the torque of a spring I was making and I just didn't have the time to build a lever adequately. I just wanted to make them consistent with each other anyway. A guy complained his was to weak so I started measuring them before I shipped them. "There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves."Will Rogers
Put the threaded pipe handle on. Mark a line 1 ft from the drill center (could be other than a foot but you will have to correct for that).
Use a scale to measure the force to resist twisting of the drill at the marked point while you are drilling with what ever sustained loading you have in mind.
The force times the lever arm (1 foot if you marked it as above) is the torque.
Edited 8/27/2009 1:20 pm ET by mike585
i have use my hole hawg to drill water wells
I use mine to drill for oil.
I thought that was why there was a threaded plug in the bottom of the pan.....
JimNever underestimate the value of a sharp pencil or good light.
I've used mine to drill Marines.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
mt starter broke so I used the hole hawk to crank the motor so I could buy a new starter. it work so good I bought beer instead
I had mine running off a 15KVA generator and drilled 4000+ holes 6" dia x 24"deep to plant dwarf apple trees. Then used a 2-1/2" auger to drill 48" deep holes to stake them. Needed an extension on the pipe handle to keep from wrapping up the cord.
Now that is impressive.
John
but where you live the water is just under the sod...
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WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
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Put drill in vise. Clamp torque wrench end in chuck. Clamp torque wrench handle down to bench. Turn the drill on and get a reading? Seems like it would work. Not very nice to the drill though.
Hmm,
good idea. Only change I would make is clamp both the drill and the torque wrench down, Tape the drill switch on, Plug the drill into a switched outlet and operate the switch with a ten foot pole.
They can't get your Goat if you don't tell them where it is hidden.
ROFL!!!BruceT
I'm not sure that would be a continuos sustained load he was looking for.
You could put some sort of clutch in between. Then take the torque up until it the drill starts to bog down. That would be the continuos sustained load.
"There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves."Will Rogers
Edited 8/27/2009 7:27 pm by popawheelie
Ok so if anyone is still listening here is what I've got.
The idea of chucking a drum with a 12" radius and winding a rope around it to lift a known weight would probably be the most accurate but at 300rpm it would lift 100' in a little over 3 seconds. You could use a smaller radius drum but then the weight would have to be increased to compensate and would become impractical to support.
So by calculation:
A 7.4amp motor at 110volts is 814watts, or about 0.9HP assuming industry standard 80% efficiency. (After I did this calculation I received an answer from Millwaukee stating 0.5HP, 1.0HP peak.)
Lbft=5252*HP/rpm
That would mean 8 lbft, 17.5 lbft peak.
Keep in mind this is very different than what you experience when it binds and you have the inertia of the armature and gearing trying to wind down almost instantly.
8 lbft is what this drill happy delivering continuously. (Partial binds while drilling may result in higher apparent torque without experiencing full stop binds.)
FWIW I've got a router that is rated at 2.0HP peak meaning its capable of drawing 13.5amps through it's 16 gauge cord. Its hard to imagine its more powerful than this 15 pound Hole Hawg. I suspect the router's normal operational horsepower is more like 0.2
John
You've forgotten to factor in the gear reduction. Figure maybe 1800 rpm at the motor, 300 rpm at the chuck, so 6:1 reduction in speed; 6X the torque.
Forrest
Based on the 12" drum it should work. 12 inches is 12 inches.
I used water in a bucket when i measured my project so I could change the weight easily.
After I had a standard i just made sure I repeated it. "There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves."Will Rogers
That would give you the stalled rotor torque. Easiest way to measure continuous torque, is to use a pump and a head column or pressure tank
I really don't think the tool owner is in any position to make accurate or realisitc measurements of torque.
In a laboratory setting, the drill would be chucked to a dynamometer. First running with no load, the dynamometer would gradually increase the load applied to the drill. The amount of current drawn by the drill would also be monitored. When the drill was drawing the maximum RATED amps, the load would be measured. This would be your sustained torque.
I agree. Short of having the "right" equipment, it is difficult to get an "accurate" measurement.
It helps to remeber that we don't have the right equiptment most of the time. "There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves."Will Rogers
That was pretty much my point.......
way back in post #2.
JimNever underestimate the value of a sharp pencil or good light.
Sorry, I didn't pick up on it.
That's pretty much what I described, other than using an ammeter to measure current.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Wow. You are in search of hard numbers. I have an old style hawg as well and it will knock me into the next county if I am not careful. Is "a wicked lot" close enough to a number for sustianed torque?
I meditate, I burn candles, I drink green tea, and still I want to smack someone.