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How the heck do I torque these nuts

rv6ehguy

Well Known Member
So I have installed my MT prop governor on the back accessory pad of my AeroSport Power IO-375 engine. I have fingered tightened the nuts on the mounting studs but now I need to torque these nuts. Anyone have any ideas about torquing these nuts? I cannot get a socket or a crows foot on the nuts. I can get an open end wrench on the nuts but that’s it. Do I need to get a special socket or make a special tool to accomplish this task? Thanks for any suggestions.
John Van Lieshout
RV6A 85%
C-FMYM (reserved)
AeroSport Power IO-375M1S 195hp
VPX Pro &PPS
Garmin G3X Touch 2 screen suite
 
You can get a wrench, but not a crows foot, on the nuts?
You can pull on the wrench with a fish scale, measuring the force; calculate the torque.
 
Make a practice nut. Use the same size bolt and the same nut. Torque it to the desired torque using your torque wrench. Then using the same wrench you will be using "calibrate" your hand.
 
You can get a wrench, but not a crows foot, on the nuts?
You can pull on the wrench with a fish scale, measuring the force; calculate the torque.

Torque a nut in a vise. Measure the torque with the wrench that you will use and a fish scale, then apply that same measurement to the nuts you want torqued.
 

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You use a dog bone wrench adapter. Has a wrench on one end and a drive adapter for a torque wrench on the other.

You may have to modify it a bit. Its tough to find one that's exactly what you want.

1Q811_AS01
 
Allen at Anti-Splat Aero makes a special wrench for prop bolts. It comes in two sizes. Make sure to order the right one or you'll end up owning one of each like I do! :)
 
torque

Remember torque is pounds times the length of your wrench (in inches or feet) times the Sine of the angle between what's pulling the wrench and the wrench. If the pull is 90 deg to the wrench then the Sine of 90 = 1, so it's not a factor.

So one pound pull on the fish scale on a 6 inch wrench is one half a foot pound or torque (or 6 inch pounds), but keep the fish scale pull 90 deg to the wrench.
 
The Antisplataero extension works great; I have determined over the last 14 years that it's the best tool for the job. Hartzell manual lists how to calculate the proper torque when using an extension.
 
The Antisplataero extension works great; I have determined over the last 14 years that it's the best tool for the job. Hartzell manual lists how to calculate the proper torque when using an extension.

It is almost always possible to insert the torque wrench at right angle to the direction of the extension, so that no recalculation of the torque value is required.

Now for the next brain-teaser: the nuts that come with the engine don't seem to be coated with cadmium. That would mean the effective strain could vary by ~2x depending on whether they were oiled or not. Are all the nuts-on-stud on the exterior of the engine supposed to be oiled? What about the ones with the star washer underneath?
 
That's a really good picture.

Opt 1: Here's a wrench from Spruce that will work

https://www.aircraftspruce.com/catalog/appages/wrench05-12375.php?clickkey=58579

Opt 2: Ask someone / mechanic at the airfield if you can give them $20 to borrow their wrench

Opt 3: You can spend $1,000 with Snap on and get a certified to NIST standard interchangeable head torque wrench and head

Opt 4: "German Torque"

Opt 5: The cheapest option is to use a combination wrench and put a double nutted bolt in the box end and use your torque wrench and the formula found here: https://www.norbar.com/Home/Torque-Wrench-Extension-Calculator

* I watched someone break 3 propeller bolts using Opt 4. Those bolts were $105 each. (Schadenfreude)
 
I love how the OP asked about torquing a prop governor, and gets advice on torquing a propeller! Lol
 
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I love how the OP asked about torquing a prop governor, and gets advice on torquing a propeller! Lol

Oh Shoot. I'm guilty. Sorry about that. Just trying to be helpful. A perfectly correct answer to a question that wasn't asked.
 
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