Weld filling drilled hole in elevator horn

Mark L · #1 05-03-2009, 01:19 PM

Recently I went back to the HS and elevators to drill the hinge bolt holes in the elevator control horns, using a drill bushing in the bearing. I drilled a #40 pilot and enlarged up to 1/4". However, after enlarging I found that there was not quite enough clearance to fit the hinge bolt & nut; the hole was drilled too close to the pipe of the elevator horn. After evaluating the problem, it appears to be due to slight angle in the elevator horns when they were welded. Every thing fit up well when they were fit when constructing the elevators.

I called Van's (they said this is a common occurance) and it was suggested that I grind down the bolt head a bit to allow for fit (the only interence on this side is due to the weld bead between the horn and pipe), and use a recessed nut on the bolt (allowing me to secure or turn on the hinge bolt). But, no joy; I cannot get the washer on and thread on the nut. There still is not enough clearance (maybe as much as 1/16"). An alternative suggestion from Van's is to fill the drilled hole (weld it full), grind it down flat again, thus repair the hole; back out the HS rod end bearings a bit and redrill.

This is where I am headed. I have friend who will fill it for me. However, I would like to get some advice from the group as to what welding material and method (Mig?) should be used to fill the 2, 1/4" holes.

Any knowlegable welders out there?

N258RE · #2 05-03-2009, 02:54 PM

I had a similar problem. twice

well two different problems,any how I filled both holes with a mig,ground them flat (I was a weldor in a former life) and re drilled the holes,

I have not flown the plane yet but it was not even a blip on the concern radar for me

aerhed · #3 05-03-2009, 07:26 PM

You can weld it okay, but hardening around the old hole can make re-drilling tricky. Have you thought of making a nice divot in the washers on either side? That way your bolt head and nut stay square. Otherwise you can plug it with a soft steel bolt, re-drill, then weld the plug after or leave it. Depends on how the plug & new hole relate.

DanH · #4 05-03-2009, 09:43 PM

Back one side of the hole with a brass or copper block, clamp firmly. Warm the block enough to sizzle spit using a propane torch or something. Now tig the hole closed, working from the outer edge inward in a spiral. Leave the block clamped in place until cool enough to handle with a bare hand.

The block does two things. The plug will be flat and smooth on one side, and the block's mass slows the cooling rate. 4130 is an air-hardening steel; slow cool equals easy to drill later.

Lars · #5 05-03-2009, 11:34 PM

Quote:

Originally Posted by DanH

Back one side of the hole with a brass or copper block, clamp firmly. Warm the block enough to sizzle spit using a propane torch or something. Now tig the hole closed, working from the outer edge inward in a spiral. Leave the block clamped in place until cool enough to handle with a bare hand.

The block does two things. The plug will be flat and smooth on one side, and the block's mass slows the cooling rate. 4130 is an air-hardening steel; slow cool equals easy to drill later.

Also gives you plenty of time to go mix a gin & tonic, and slice a lime to perfection while you are waiting.

robjohnson · #6 05-04-2009, 04:23 AM

Buy a single flute drill bit from McMaster-Carr -- I had to have mine welded twice (first one misdrilled...the second messed up during drilling because of the hardness of the weld). Did a bunch of research and found that a single flute bit was the ticket. It went through the weld like butter! I started with #40 and then stepped it up to final size.

robjohnson · #7 05-04-2009, 04:28 AM

Also, I would TIG it closed, not MIG. TIG keeps the heat impacted area close and there is no splatter like MIG. Lincoln Electric has some guidance on TIG filler for 4130. I used ER80S-D2 on mine. Here's a link to their site --

http://www.lincolnelectric.com/knowl...hrome-moly.asp

RV8Squaz · #8 05-04-2009, 09:15 AM

I had mine professionally filled/welded and ground down. I didn't do the welding so I don't have specifics on that. What I can tell you is that I have 350 hours on my -8 with lots of aerobatics flown between -2 and 5 g and the filled hole is of no concern. The area looks great.

Jerry
RV-8 N84JE flying since Feb 4, 2007

24Golf · #9 05-04-2009, 09:18 AM

We welded ours and re-drilled - No problems...

swrankin · #10 10-25-2010, 08:12 AM

Quote:

Originally Posted by DanH

Back one side of the hole with a brass or copper block, clamp firmly. Warm the block enough to sizzle spit using a propane torch or something. Now tig the hole closed, working from the outer edge inward in a spiral. Leave the block clamped in place until cool enough to handle with a bare hand.

The block does two things. The plug will be flat and smooth on one side, and the block's mass slows the cooling rate. 4130 is an air-hardening steel; slow cool equals easy to drill later.

Does anyone know of any TIG welders in the Kansas City area with experience performing this repair? So far I've only come across gas or MIG welders.....must be a geographical preference or something. :-)

Thanks