NEW! Ultimate C/S Prop Wrench Anti Splat Aero

[gasman]

Originally Posted by Rv8ter

all this discussion has the basic principle of torque changed?

In most wrench applications the force relationship may be expressed by the following formula:

F x D = T
FORCE x DISTANCE = TORQUE

Where:

F equals turning force in pounds applied by the Operator.

D equals lever arm or wrench handle in inches or feet.(Whatever the distance)

T equals total force applied to wrench head in pound-feet, kilopoint-meters or Newton-meters

I'll just continue to keep it simple!
My money is with Allan on this one!

The argument is not over the basic principle of torque.............

The argument is over "How A Torque Wrench Functions."

[PerfTech]

Originally Posted by gasman

The argument is not over the basic principle of torque.............

The argument is over "How A Torque Wrench Functions."

I am not making any statements as to how anyone's torque wrench functions, where they should grip it or advocating the use of a piece of pipe on the end of it. I am saying how to properly use our tool or any torque adapter and will try to shoot a video tomorrow night. In this case "IT aint over till the fat guy makes video"

[380mxc]

Originally Posted by PerfTech

All foot lb. torque wrenches are the same regardless of handle overall length. The overall length only effects how hard you need to pull on it. on a foot lb. torque wrench the .8 multiplier is exactly and always the number. It is not rounded off and it never changes as long as the crows foot or our tool is 3" and in installed straight.

This statment is the one in question. And the safe use of torque wrenches longer than 12"

Safety first.

[PerfTech]

Originally Posted by 380mxc

This statment is the one in question. And the safe use of torque wrenches longer than 12"

Safety first.

You don't need to talk safety to me. If you have been to our web site you would be aware that all of our offerings are pointed to improve safety. We have invested many thousands in developing and importing products for the RV community. I intend to address this safety issue is my video that will be up in a few days. After posting the video, I will put the prop wrenches up again in the classifieds, for now I won't sell any more until this is put to bed. Allan

[WAM120RV]

Hey Allan you will always be one of the Good Guys in my book!

Keep developing items like this, dont let this little side show stop you coming up with good engineering solutions.

I think your nose job is great and I might be in a position to order one next month, hopefully Peter will have got his through the UK system by then.

[444TX]

The debate here is the accuracy of using the x .80 conversion for getting the desired fastener torque when using a 3 inch torque extension regardless of the torque wrench effective handle length.

Any debate on where to grip the torque wrench or adding extensions to the handle has little merit. The wrenches are calibrated with the handle pulled at a particular spot and videos show that final torque can be effected by hand position. Using a different technique would require verification to show accuracy. Just because it clicks or indicates a value does not mean that the indicated value is the same as the fastener actual torque value without verification.

The industry standard is to use the formula in FAA AC 43.13-1B (chapter 7), instructions that come with the torque wrench or the formula posted in this thread. They are all the same. The result of the formula is different for different torque wrench effective handle lengths. When using a 3 inch extension the .8 formula only works with a 12 inch effective handle length.

I have a digital Snap-On 1/2 drive torque wrench with an effective handle length of 22.18 inches (total handle length, center of square to handle end, is 25.375 inches). Using the 43.13 formula when torquing a Harzell prop to 65ft/lb the S-O wrench would require a 57.25 ft/lb indicated setting/reading when using a 3 inch torque extension. If the .8 formula was used with the S-O wrench, the indicated wrench setting/reading would be 52 ft/lb (65 x .8). When taking the 43.13 formula and converting the indicated 52 ft/lb (from the .8 formula) back to the actual torque at the fastener the result is 59.03 ft/lbs. If the widely accepted formula is correct, the fastener would be under torqued by almost 10%.

Using a 60 ft/lb desired torque (the minimum Hartzell torque value) one would only get a fastener torque of 54.49 ft/lb using the S-O wrench, 3 inch extension, .8 multiple for the desired torque and running the numbers backwards with the industry used formula. 5.51 ft/lb below the recommended minimum torque.

There is actually more going on here than simply adding a longer arm to get leverage. The torque wrench is only measuring the twisting force centered on the drive hole in the torque extention. The second force is the pressure neccessary to move the torque extension in an arc centered on the torque extension pivot point. (post #296) The 43.13 formula takes this all in to consideration.

I like Allan's tool and may purchase one. I am still waiting for his video and would hope there are torque wrenches much longer than 12 inches used in the comparison.

George
RV8

[PerfTech]

I set up and shot some video tonight and need to do a little editing (to long). Should post in a day or so. Regards all, Allan

[erich weaver]

Those exclamation marks from Allan look awfully enthusiastic...

Erich

[LAMPSguy]

Originally Posted by Mel

Because.....IT'S A TOOL!!!!!!!!!

You don't need an excuse to buy a tool!

I once explained this to my wife, told her if she needed a gift idea, find a tool I don't have, made in USA, and buy it!

[swordtail]

if you can find it, snap-on form SS428A-3A called "Bolts, Tension and Torque"
16 pages of answers. or form SB565A titled "Torque Problems" or SS1276 called "threaded fasteners & torque" if you can get them. The formula that we used for extensions and adaptors. Lever length of the wrench is extended
reading correction required! Calculation is requiredto find new reading (NR)

NR = L X T / L + E where T is torque value required
L = length of torque wr from
hand position to center of sq drive
E= extension length from center of sq
to center of hex.
NR= dial numeral representing torque value required
formula are tough in a post but I hope you get the idea.