MD3614M Rod End Bearing

[msmst25]

I'm trying to install the rod end bearings into my elevators, but the holes in the spar and hinge reinforcement plate seem to be too small to even insert the rod end bearing through to the nut plate underneath. All 4 of the holes are too small, and I've tried multiple rod end bearings. I don't see anything in the instructions that indicates I should have enlarged this hole prior to installing the nut plate. I'd appreciate any suggestions.

[msmst25]

With my calipers, it looks like the holes are about 3/1000 too small for the rod end bearing. I'm considering just using my unibit and slowly entering to enlarge to a full 3/8". I just don't want to take a chance on ruining my elevators if there is some reason this isn't a good solution

[walldan]

Before taking the Uni-bit to it I would call Vans or wait for others to reply..

[AlpineYoda]

I'm unclear where you are in the build - can you cite a page and step number?

As I recall, the VA-101 threaded inserts were really hard to insert into the pushrods, especially after priming the inside of the pushrods. I had to file down the VA-101s a little bit, and then use a rubber mallet to drive them in. Is that the part you are referring to? The same thing happened again for the aileron pushrods.

[Dean Pichon]

My recommendation is to open these holes as little as possible (3/8 reamer, drill, Unibit) to get the proper fit to the HS. However, before you rivet the Nut Plate to the spars and doubler(s), open the hole a bit (perhaps with a "W" drill or reamer (0.386")) in order to ensure the rod end will properly engage into the threads of the Nut Plate even in the case the Nut Plate is not exactly concentric with the spar/doubler assembly.

Good luck,

[msmst25]

The elevator is already assembled. I’m on the first step of the assembly of the empennage. I didn’t think that I would need to check those two pieces to make sure that the hole was the right size. I like the idea of using a 3/8” reamer. I think I’ll order one of those unless I hear a better suggestion. I think that will give me a cleaner hole than the unibit.

[Bill.Peyton]

Are you sure you have the correct rod end bearing?

[AlpineYoda]

I see where you are now. I don't see anything about enlarging those holes, either. A few basic things to check (not to insult anyone's intelligence - we all make avoidable mistakes). Are the plates overlapping properly? All four holes have both the spar and a reinforcement plate. Is it possible that you didn't keep the four pairs together? Is it possible that the center hole for the rod bearing isn't aligned?

Did you use a K1000-6 nutplate for all four holes? Maybe the problem isn't the holes, but rather the wrong nutplate?

Looking briefly at my elevators, the fit isn't 3/1000 inch, like you suggest. There is enough of a margin for error that if my nutplate was off by a little bit from dead center (and I'm sure it is off a little), the bearings still would fit through the hole into the nutplate.

Or, maybe Van's CNC process made an error somewhere.

Be careful with a unibit or reamer widening that hole - since you have a nutplate installed in each hole, if the unibit pokes through too far, you will damage it.

If you need to increase the diameter of the holes without hurting the installed nutplates, one option would be to use a narrow sanding or grinding tip in a dremel - just poke the tip in there and sand out the edge until the hole is wide enough.

[flion]

Don't be quick to enlarge those holes. Lots of builders and no one else has been reporting an issue. And it's unlikely that Vans has changed anything. My guess (already mentioned by another poster) is that you have the wrong bearings. Double and triple check. Here are the dimensions for that series of bearings, check the housing width and thread size. It's pretty easy to mix up the bearings, so if Vans made a mistake, it would most likely be there rather than a CNC error.

[David Paule]

Sometimes local hardware stores sell reamers, usually the fractional sizes like 3/8".

Dave