bhassel

bhassel

Well Known Member
Steps 1 & 2 have you install the HS-1213A & HS-1213B hinge brackets to the Fwd spar. What it doesn't say is what the torque value is of the AN3-4A bolts going into the K1003 platenuts or the AN3-12A bolts used for the stops going into a AN365-1032 nut.

I believe that the later torque should be 20 - 25 inch pounds. However, I'm not sure of the torque value of the bolts going into the platenuts.

Bob
 
Checking the running torque

Ok, what we have been doing is using a beam type torque wrench to check the friction torque of the lock nut or plate nut. We have a 1/4" drive wrench for the small fasteners and a 3/8" for the bigger ones. We then add this to the hand book torque for that fastener size.

The beam wrenches will do most all the torque readings but the snap over type wrenches are more convenient, so we have both types.

You use the torque wrenches a lot in building the plane and later maintaining the plane, so I have always considered them a good investment.

Tony
 
Tony,

I tried the beam torque method of measuring running torque, but could never get a reliable reading. What were the typical values were seeing? On my landing gear bolts I decided the running torque was probably less than the torque range and just torqued to the high end of the range.

Rich
 
The values can be found in the little book they send with the kit. I bought a pretty low (50?) in/lb beam. It's surprising how quickly you can over torque a 10-32.

A general rule - never over tighten anything on a plane. If it falls out replace it. I've not run into anything critical that doesn't use a safety of some sort. And do not ream out nutplates - they are bent for a reason.
 
Water boy,

I think you misunderstood my question. I am asking what typical values of torque people are seeing to freely turn a self locking nut. I found them so low I could not get a reliable reading on a beam torque wrench.

Rich
 
RFSchaller said:
Water boy,

I think you misunderstood my question. I am asking what typical values of torque people are seeing to freely turn a self locking nut. I found them so low I could not get a reliable reading on a beam torque wrench.

Rich
Click to expand...

Rich, that is not really an answerable question.

There are at least 4 different types of self locking nuts used on the RV-12, and the prevailing torque on every one of them is different.
The standard AN365 type have a prevailing torque that is relatively low, and the small all steel MS self locking nuts have a P.T. that is quite high. The others fall somewhere in between.
 
Sorry, I did misunderstand the question. After re-reading the thread starter I don't think I could have done any different.

In any case, you're over thinking it. The rule for locking hardware is if you can thread a lock by hand it's garbage.
 
Scott, the reason I asked is because the landing gear mod instructs the builder to add the running torque if torquing the bolt head as opposed to the nut. I never could get a running torque value because it is at the low end of indication. I ended up just torquing to the high end of the range reasoning that the running torque was less than the difference between max and min recommended values.

I was looking for some validation in my assumption.
 
I ordered a Park Tools TW-1 (1/4 inch) torque wrench from one of the local bicycle shops. It's 0 - 60 inch pounds. I found that the AN365 are around 12 inch pounds of rotational torque added to the bolt torque. I was really surprised that the nutplates were about the same!

Bob
 
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