Bravo Mike!!!!
This is the best post so far!
Actually the best post so far Allan is the first post of this thread where you offer this wonderful tool to those of us who have fought the battle too many times taking a C/S prop on and off.
Bravo Mike!!!!
This is the best post so far!
Good...
Because I'm aware of everything you just said. But, it doesn't explain, what I'm looking for.
I've spent the last two days, scouring the Internet for the exact info I want. I've linked to numerous calculators. I don't need to hear anymore ...re quoting of the same numbers.
Ultimate C/S Prop Wrench
We have completed our testing and development on this product and now are offering them for sale. Please have a look at the demonstration video below. If you have a constant speed propeller or work on airplanes you will definitely want one of these. Let us know your opinions. Regards all, Allan
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http://antisplataero.com/Videos.html
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http://antisplataero.com/Products.html
The wrench appears to be made from two pieces bonded together to double the thickness... how are the two halves bonded together?
Here's a video I just made answering one of the questions that I think Larry was asking and Steve clarified. Does it matter where you hold a clicker type torque wrench. Intuitively you would think it shouldn't matter much. But as you can see using a Snap-On 100 ft-lbs clicker torque wrench set to 25 ft-lbs (300 in-lbs) and pushing against a Snap-On 600 in-lbs dial torque wrench, there is a significant error when pushing in the middle of the wrench instead of the handle. I don't know exactly how the mechanism works but I know it's calibrated using the handle.
http://youtu.be/_1LZk0jnQrA
By the way, this clicker wrench just happens to have an effective length of 12 inches so it should work perfectly with Allan's wrench and a .8 multiplier.
OK Larry, You are correct and I feel like it is time to explain this with the true numbers and set everyone's mind at ease. This discussion has been absolutely wonderful for us and since Sunday PM we have sold all but nine from our first run of 400 wrenches. Thank you to everyone for your support.
So here goes! First lets get the numbers established we are working with. To make this easier we will use 100 ft lb as the called out torque (ft lb is based at 12"). So 12" = 100% without our wrench. Our prop wrench is exactly 3" center distance. You take the 12" divided by 3" = 4 times or 25%. Now you add the 12"+3"=15" or 125% with no correction you would be over torquing to 125 ft lb with our adapter. So you must divide the 100 ft lb call out by 1.25. 100 / 1.25 =80.
thus the .8 multiplier. Using a 3" adapter you must set your ft lb torque devise (what ever it may be) to 80 ft lb to achieve 100 ft lb at the bolt. This is the math and nothing will change this fact. I hope I haven't offended anyone by presenting this in it's simplest form. I just want to clarify this to everyone. Love this forum and all who use it. Allan
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PS Keep an eye on our web site as we will be introducing several new products in the coming weeks.
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...This discussion has been absolutely wonderful for us and since Sunday PM we have sold all but nine from our first run of 400 wrenches. Thank you to everyone for your support...
Allan, your explanation is still invalid, your math is still wrong, and the torque values that follow from them are dangerously under-spec for any torque wrench with a handle longer than about 18". Several engineers, both mechanical and aeronautic, have clearly explained why that is so.
The fact that you so cavalierly exploit the controversy you have stirred up here to increase sales suggests that you do not have your customers' best interests at heart. I hope that that is not actually the case.
Thanks, Bob K.
Bob; My explanation is absolutely valid, my math is perfect and the torque values that follow from them are spot on. I graduated top of my class at MIT with three degrees in mechanical engineering with specialties in stress analysis and metallurgy. I have over forty years experience in tool design, owned and operated Omega Tool Co. (A company with 6 m $ yearly revenue specializing in the development and manufacture of specialized aircraft tooling). Believe me when I say, "I do not make mistakes with Jr High math".
As for your accusation that I have somehow stirred up a controversy, down rite ridiculous! I posted a top of the line product at a very low price with clear, concise instruction in it's use. The controversy was generated by the very small camp that has a problem understanding this simple mechanical concept. They passed their confusion on to others who truly wish to understand. I will rectify this misconception early next week when I return from my business trip on Tuesday the 21st. Keep an eye out for the video as it will be very entertaining as well as informative. Thanks,Allan
...We are not trying to re-design some manufacturers already built torque wrench with a cheater bar. If one desires a longer tool then buy one. What I said was "If you are using a foot pound torque wrench .8 is the multiplier with our tool". Regardless of your having a 12", 18.77", 23.842" 31" or a 99" or any other length commercially manufactured foot pound torque wrench at 100 ft lb they will all read, click bark or chirp at the same time when set to 100 ft lb.
If you want 100 ft lb with our prop wrench in the mix you will need to set them all at 80 ft lb. to get your desired 100 ft lb. The videos posted verify this exactly. I'm not manufacturing cheater bars, nor advocating their use, we are making a very high quality torque adapter that will perform flawlessly used as directed. Thanks, Allan
Poster #1, who still believes they are...... I have no idea who came up wtih the idea of clicker wrench being different..
Somebody please get Chris a different length torque wrench so he can redo the experiment.
Please do it!!!!
This might explain the question of the length of the torque wrench. http://www.tegger.com/hondafaq/torque_wrench/index.html
Read down to the cutaway view of the barrel.
As I see it, this rather interesting article proves that the length is irrelevant to the operation of the click style wrench.
Once you have a tube long enough to hold the parts, it just doesnt matter. What matters is the force the spring exerts on the tilting block.
Different size spring and adjusting screw etc will still allow exactly the same functionality in different length handles.
Thanks for sharing that link.
Correct - at the wrench head where the torque is sensed. The wrench will 'click' when the *head* reaches the torque you've set. The torque 3" (or any other non-zero distance) ahead of that sensing mechanism very much depends on the length and the force you're applying to get the selected torque at the head...as has been shown in this thread.As I see it, this rather interesting article proves that the length is irrelevant to the operation of the click style wrench.
Correct - at the wrench head where the torque is sensed.
...The moment (or torque in our case) along the beam is given by the linear equation M(x) = P * (L-x) where M is the moment, P is the force applied at the handle, L is the overall length of the beam, and x is a distance from the cantilever fixed end (the bolt in our case)...
Reiley, I think that this discussion would have died a timely death a long time ago, except for the fact that it revolves around a very important, flight safety issue...
I was taught that proper "counter torque" was critical when using the wrench. Bob, does the math prove that it makes a big difference? If so, where do you place the other hand for the counter force...at the nut or at the connection to the extension?
This takes the length of the arm of the torque creating device out of the equation completely, other than Allan's tool there is effectively no arm to figure
Mike,
There is no torque without an arm. Calculate the force on the arm to react against the motor torque and you are right back to a simple cantilevered beam.
Bob,
...probably using .8 wouldn't cause any problems since most everyone's torque wrench is probably close to a foot long...