Bolt torques


Jay Scheevel
 

Has anyone ever documented if there is an appropriate torque for the AN4 bolts that pin the torque tubes together on the elevator and aileron linkages, or is it "just tighten until it feels right"?  Thanks.

Cheers,
Jay Scheevel, Tri-Q, still building



Richard Thomson
 

Hi Jay,

You say AN4 which I presume you are relating to the elevators, the ailerons runs are AN3, unless I have missed a mod.

It partly depends on how good your hole tolerance is, I used a 3/16th Taper reamer to finish the holes and they are spot on, so no slop with the bolt.

I used a bolt length that made sure the shaft was bearing on the shank both sides, and a washer, or two if necessary, each side then just snugged them down so they wouldn't freely rotate.That way there is no shear on the thread.

If you use a torque figure it may deform the pipe and preload the bolt.


Richard T.


Jay Scheevel
 

You are right Richard, I did not think to state that the ailerons are AN3's. Good point about the shank. I will check that. In any case, I am sure my holes are not as precise as could be, but I can use the hole reamer to check/improve. I have deburred them. I am presuming that the bolt tension and associated friction is what eliminates slop in the control system, since only a thousandth or two will show up as some play in the controls. Small torques should not distort the tube too much since it is fairly thick walled steel, but trying to find the happy medium between distorting and providing adequate clamping force that would provide enough friction. Just thinking out loud here... Thanks for your input.

Cheers,
Jay


Sam Hoskins
 

Tighten them down until the wiggle is gone. Use fresh bolts, nuts and washers. 

Sam

Sent via wireless Gizmo.

On Jul 20, 2017 6:19 PM, "jay@... [Q-LIST]" <Q-LIST@...> wrote:
 

You are right Richard, I did not think to state that the ailerons are AN3's. Good point about the shank. I will check that. In any case, I am sure my holes are not as precise as could be, but I can use the hole reamer to check/improve. I have deburred them. I am presuming that the bolt tension and associated friction is what eliminates slop in the control system, since only a thousandth or two will show up as some play in the controls. Small torques should not distort the tube too much since it is fairly thick walled steel, but trying to find the happy medium between distorting and providing adequate clamping force that would provide enough friction. Just thinking out loud here... Thanks for your input.

Cheers,
Jay