Torque wrench substitute


#1

I had read somewhere you can substitute a 3foot ‘cheater bar’ on the end of a ratchet and a persons body weight on the end of this bar to produce reasonable accurate results. Example, 150 lb person equals 150FT Lbs, 200 lb person equals 200 FT LBS, etc. I realize this is not the correct way to torque a fastener to specs, was just wondering if it actually works?? Thanks


#2

Good Lord no!

A three foot bar with a 200 pounds of force will produce 600 pound feet of torque!
Perhaps this website will help you to understand torque better.
http://www.solarbotics.net/bftgu/tutorials_mech_torque.html

Oh, and a 200 pounbd person putting all his weight on a three foot cheater bar attached to a ratchet will probably break his head when the wratchet breaks and he comes crashing to the ground.


#3

This is not an acceptable substitute, and your formula is not accurate. To achieve 150 ft. lbs with a three foot bar, you would exert 50lbs of force on it. A foot pound is a pound on a one foot bar. A 150lb person on a three foot bar would produce 450 ft lbs. That’s close to what lug nuts on a semi are torqued to.


#4

I think you would need the 150/200 pounds only 1 foot away from the socket. If you put 200 pounds at the end of a 3 foot cheater you’ve got way more than 200 ft/lbs of torque.

Somebody smarter than I will explain this more accurately.


#5

It’s pretty simply really. One pound-foot of torque is one pound of force applied one foot from the axis. Multiply the distance from the axis X the force.

Visit the website I suggested for more clarity.


#6

Thanks for the reply, the torque website you suggested was a little complicated for me, but the 1 foot, 1 pound, from the axis makes sense. The idea for the cheater bar came from a ‘car repair for dummies’ type book I had read somewhere. They were talking about torquing the rear axle nut on a Volkswagen Bug (150 FT LBS) when a torque wrench wasn’t available.


#7

a 150 lb person putting all his weight on 1 foot from the axis would be an excellent way. The one caveat would be that the socket be no longer than necessary to fully engage the hex, without an extension, and the wrench be the proper size without adapters. The further away from the hex you get, the more difficult it becomes to keep all of the force as torque.

Equipment is calibrated by using laws of physics, and the way a torque wrench is calibrated is actually by putting a measured exact weight exactly a specific distance from the rotating axis and checking to see what the wrench reads. Said simply, the one pound-foot increment on a torque wrench would be calibrated by putting a one pound weight exactly one foot from the axis and seeing what the wrench reads. Any variation is considered “error”, and if required a “compensation chart” is generated from these various error readings.


#8

I don’t like the 150ftlb figure for the VW axel nut, it sounds too low. Is this actually what you are tightening?


#9

‘car repair for dummies’ type book

[i] How to keep you VW alive
    A step by step manual for the complete idiot. [/i]

#10

My book shows about 217 Ft. Lbs on the rear axle nuts for Types 1 and 3 so oldschool is correct.
Type 2 is shown with a huge variance depending on production date and chassis number; 217 or 108, all depending.


#11

I was trained to tighten this nut as tight as my CP 734 impact would make it (boy was I proud the day I bought my first impact, I was 18 and that was beer money going to waste for a tool). To get some extra power out of the impact we would add some transmission fluid down the air intake of the impact and turn the socket you were using back into the hammers of the impact.


#12

Possibly, this was over twenty years ago that i read it.


#13

Didn’t have any idea this would generate such a response!! The actual vehicle is a dodge truck (2wd) the part is the spindle nut that holds the hub on. The manual said torque to 185 FT. Of course I didn’t have a wrench that would go that high.


#14

I’m real curious as to which spindle nut that is, chuck. And as for responses, this place has more advice and opinions than a politician. But unlike a politician, some of the advice here is good.


#15

I found a 185ftlb torque value on a 2002 Ram1500 front halfshaft to hub nut but you say 2wd. This value is in the 130ftlb range. What yesr/model, nut are we talking about?


#16

So, you are the guy at the tire store that makes me use a 5’ cheater bar to get my lug nuts loose so I can torque them down. With Harbor Freight having 1/2 " click type torque wrenches on sale frequently in the $10-$13 range everyone should have one.


#17

Many auto parts stores will loan out tools like this for free.


#18

Ah, bought one, used once, great. Then was doing a pan drop and ATF change on my other car 3 months later and the Wrench was not working. Had to use my elbow/brain correlation ratios and got lucky with no ATF leak. Though the thing has a lifetime warranty and they gave me a new one.


#19

Wasn’t me that worked your lug nuts over as my traing also included instructions not to apply the “tight as you can get it” technique to every nut I came accross.

I conclude you don’t have any experience with the paticular axel nut we are talking about. Many DIYer’s never got this nut tight enough and the result was the wearing away of the splines in the drum by the cooresponding splines on the axel. When the drum lost its splines like this the “bug” did not move. Many people got scammed into buying transmissions they did not need because of this.


#20

Sounds like me. My first impact was a CP 734 and it was a good one too. Apparently too good because I came back from lunch one day and it was gone, along with the quick disconnect on the air hose after someone unplugged the air hose and cut it off.