Supersized elevator horn holes-what to do?

[dsmithlib]

It was all going so well. Horiz stab, elevators. Then the time came to drill the holes in the elevator horns. After lining up the trailing edges, I got out the long #40 bit and drilled those holes with no guide between the horns.

Well, the holes are out of alignment. Putting the AN3 bolt will surely pull the elevators out of alignment. So, I started working the holes with a file in hopes of getting them from #40 up to 3/16. I pretty well got the alignment straightened out but, one of the holes is now an AN3-1/2. The elevator horn hole on one side is about 1/32 oversize. This just does not seem like the place to tolerate it.

I am considering stepping up to AN4 with a new $45 rod end from Spruce.

I have also thought about just putting an external lock washers on either side of the over-sized hole in hopes that it would prevent the 1/32 play in one of the elevators.

I am also looking for a good way to ensure that the elevators are lined up correctly.

I will never, ever freestyle drill again!!
Feedback appreciated......

Dave

[MauiLvrs]

Weld it up....
Start over....
Carefully follow the instructions to be sure that the holes line up...

[DanH]

Swap the rod end and drill or file for an AN4 bore, or weld up the oversize hole and drill again....either is fine.

The lockwasher approach is unacceptable.

[fixnflyguy]

You arent the first to do that ! I have repaired 2 other horns with the same scenareo for fellow builders. It can be easily welded with the horn still on the elevator assembly. After its carefully ground down, you wont even be able to tell. Both of the aircraft I repaired have been flying for over 10 years with no problems. If the weld is allowed to cool slowly, there will be no side affects of hardening.

[mike newall]

Weld it - that's what I had to do on our 8

Followed the instructions, drilled the correct horn but then realised that one horn was slightly twisted up relative to the other.........

This is our second, so I am a little embarrassed.

Anyhow, took it to my mate who glued the hole up with CMS32 rod, I fettled it back - you couldn't see the weld ! He is a very clever chap.

Redrilled - this time from the other side - no problem.


Hey Dan - That new Avatar looks a hoot !

[rv9av8tr]

Originally Posted by MauiLvrs

Weld it up....
Start over....
Carefully follow the instructions to be sure that the holes line up...

I had to do the same thing.

[rv7boy]

Mike,
How refreshing to learn some new word today. I did not know we could fettle back our elevator horns.

Seriously I did not know what fettle means until I read your post and then looked it up.

Thanks. Add another reason to read VAF every day. I hope to visit the Motherland someday.

Don Hull
Descendant of George Hull of Crewekerne, county Somerset, England who arrived in New England (Connecticut) in 1630.

[Greg Arehart]

An alternative approach might be to bolt a plate of 0.063 steel on the side of the horn (outside, cut the plate to fit closely within the horn flanges), drill it straight, then bolt another plate on the other horn and backdrill it.

greg

[lorne green]

Yup, weld it up and re-drill the horn. Even though the repaired hole surface will be harder because the welding rod material is harder,
it will drill easily with a sharp bit because the horn leg is so thin. My one horn was five bucks to weld up.

[6 Gun]

Im fixing to take tail group off my project to paint when i take it off im going to put horz on saw horses with elv on horz and drill hole for push rod whats the trick or tool to get it straight.
bob