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I recently ordered and received the Aurora Rod End Bearing called out in the plans for the Ail push rods. I ordered the alternate WM-5's as called out. I expected the bearing to have the "witness" hole as shown in the plans. They of course came with no hole. I saw on a couple of builder site that they drilled #40 holes themselves. I wanted to poll others out there and see what they did. I have concerns running a drill bit through the rod ends. Won't this weaken a critical part? Thanks.

Jason Smith
Sonex #460

It's not a problem, Jason. I see no need for a #40 though. One only needs the size required to "witness" the threads. Drill a smaller hole. I was surprised how easily the rod end metal is drilled. It seems soft...

I bet the threads weaken the part a lot more than a small hole.

Jason wrote:I recently ordered and received the Aurora Rod End Bearing called out in the plans for the Ail push rods. I ordered the alternate WM-5's as called out. I expected the bearing to have the "witness" hole as shown in the plans. They of course came with no hole. I saw on a couple of builder site that they drilled #40 holes themselves. I wanted to poll others out there and see what they did. I have concerns running a drill bit through the rod ends. Won't this weaken a critical part? Thanks.

Jason Smith
Sonex #460

I had the exact same concerns. There actually is a very obscure note on one of the related pages in the plans showing just where to do the drilling. I cant get to the plans just now, but that note was in the upper LH quadrant of what ever page it is on. I felt sort of sheepish as I had to ask Kerry about those holes.! :)

The call-out is on SNX-C01, Detail K, top left portion of page.

Witness hole is drilled 5/16" from end (threaded end) of bearing. A 1/16" hole is good for this witness hole.

Maximum distance between end of rod bearing and start of pushrod tube is 15/16"

I know this is an old thread, but I just got to this where I am fitting the rod ends to control rods. The rod ends that I have are MW-5's which do not have the witness hole. I drilled the witness hole - easy enough. But just a note to anyone else doing this in the future... The MW-5 has quite a bit of grease in there and after drilling, lots of metal. Clean it out very well, run a threaded rod through there a few times, then clean it out again. Then add new grease.

I just attached the flap push rod to the flap drive plate. It seems to me that hole in the drive plate would be subject to wear easily due to the force on it in flight during use. I'd think enlarging that hole to insert a press fit bronze bushing would be a good idea there. Then the bushing could be replaced in the future if it wears.