Forward pushrod end bearing thread depth?

[Nashpdman]

I've just completed the forward push rod, F-1089. I'm only getting 3/8" of thread depth on the rod bearings when I set it to 37-13/32" as referenced on pg 39-3 figure 3. This seems kind of shallow to me. Can anyone advise, is this normal? I've rechecked and verified the measurements (33" tube) and I'm using the correct rod bearings.
Thanks!
Mike

 

[BobTurner]

I don’t have the plans in front of me, but my recollection is that the two rod end bearings were identical. The two you show are different lengths (I counted the threads). Maybe my memory is faulty. When properly assembled there should be more threads inside the tube than showing outside the tube, both ends. That way even if the jam nuts fail you cannot ‘unscrew’ the push tube - one end bearing will come tight before the other falls free.

 

[gkochers]

I don’t have the plans in front of me, but my recollection is that the two rod end bearings were identical. The two you show are different lengths (I counted the threads). Maybe my memory is faulty. When properly assembled there should be more threads inside the tube than showing outside the tube, both ends. That way even if the jam nuts fail you cannot ‘unscrew’ the push tube - one end bearing will come tight before the other falls free.

This is the one pushrod where that is not true though. That’s why this pushrod gets safety wired to prevent rotation.

 

[Nashpdman]

I don’t have the plans in front of me, but my recollection is that the two rod end bearings were identical. The two you show are different lengths (I counted the threads). Maybe my memory is faulty. When properly assembled there should be more threads inside the tube than showing outside the tube, both ends. That way even if the jam nuts fail you cannot ‘unscrew’ the push tube - one end bearing will come tight before the other falls free.

Hey Bob, I thought that was odd too but that's what the plans call for. I'm not sure what the issue is...

 

[wirejock]

Not a 10 but I cut all my pushrods longer than plans. They all fit and the last check before torquing jam nuts was to spin them all the way to one end and shake.

 

[Ralph Inkster]

I think the longer (forward) rod end is intended to clear the bell crank fork through its full motion. If you happen to put the link in backwards, the VA-111 may interfere with the bell crank.

 

[Richard Connell]

It’s to make sure the front of the F-1089 dosent interfere with the tie F-1065.

Don’t “make the pushrod longer” or otherwise apply your own or other peoples interpretation to it.

Build it exactly as plans and read ahead to where it tells you how to safety it such that it doesn’t back out - because it is one of the rare places where it can as the rod ends don’t engage beyond half way.

 

[Nashpdman]

I believe my solution will be to use a MD3616M (1.812) in place of the MD3614M (1.375). This will give me .425 additional length of threads and leave the tube as built. I'll watch to make sure there's no interference with F-1065. This may not be necessary, but it'll make me feel better. I'll call Van's to verify

 

[scsmith]

The amount of thread engagement you show is plenty for strength. You have about 1.5 diameters of thread which, even threaded into aluminum, is plenty strong. Setting aside the concern about the pushrod rotation being able to unscrew one side, this looks fine. The thread engagement to prevent unscrewing one side is a standard practice, and if the plans discuss it and provide an alternate means of secondary protection (safety wire) then I think you are good to go.

 

[Walt]

Every time I inspect a 10 that connection is always a bit of an eye opener, it just doesn't look right even though it is ok.