Chamfer on rudder drive horn

[dxlusby84]

Greetings builders!

Just started my tail kit and am working on the chamfer of the drive horn.... I think i understand that the purpose of the chamfer is to allow the horn's pilot holes to align with the factory drilled holes on the rib... The chamfer allows the horn to clear the radius on the rib's corner...

However, after painstakingly edging up to the 1/16th chamfer, the two sets of holes wont line up... Have i misinterpreted the goal? Should I chamfer more than the prescribed 1/16 inch?

Thanks,
Devin

[Area 51%]

If the side and bottom of the horn are both touching the rib at the same time, then you've chamfered enough. In that event, it's just one of those instances the factory should have only put holes in one of the components and let the customer align and drill. I had no holes in the Legacy rib.

How much of a mismatch are you looking at?

I'm curious if they fixed the T04-06 hole mismatch yet. That's assuming you're building a Waiex. Keep us posted.

[dxlusby84]

So at the instructed 1/16 chamfer, id guess the part holes interfere by a 32nd? But its enough to make cleco insertion difficult and cause a bend because the horn's chamfered corner still interferes with the ribs rounded corner... Hopefully the attached pictures will help clarify.

[Bryan Cotton]

I would chamfer until it fits. I sort of remember a lot of chamfering on that part. My chamfering was a little more rounded so it fit the inside bend of the rib.

[dxlusby84]

Let me ask a general follow-up... How literally should i interpret the plans? The reason i didn't wish to go beyond a 1/16 chamfer is because presumably the plans don't want you to remove too much or too little material... Where should i take liberties... How do i judge whether i must decorate to overcome a manufacturing or design inaccuracy... I'd think, especially given my newness to building that I'd be on the more strict side of adhering to the plans and instructions...

[Bryan Cotton]

To be safe, you can always contact Sonex tech support and ask for guidance.

[Rynoth]

Are the holes in the pics still pilot holes (#40)? If so, that looks close enough for them to match up when updrilling to #30 (provided the alignment of the parts is otherwise correct.)

[dxlusby84]

They are #40 pilot holes in the horn, yeah... Factory holes in the rib, of course ... Holes line up great if i set the rib on top of the horn, so i know the holes themselves are good... Just got to sort out the chamfer so when the horn is set inside the rib, they live up with a nice flat mating...

[dbdevkc]

It looks like you either need to chamfer a bit more, or take a little off the edge of the horn to get the hole to line up perfectly. Have you already smoothed out any roughness on the edge of the drive horn? Looks to me just a tiny bit more taken off with a scotchbrite wheel would allow the holed to line up. When doing those kinds of adjustments, just be careful of hole edge clearance. In this case it doesn't look like you need to take too much so it shouldn't be an issue.