Drilling holes in repaired landing gear fittings

[james gevay]

Ok, here's a few more questions on the gear fittings. Like my other recent post on the longeron stab fittings, these gear fittings were welded at the same time.
The IA found a couple of cracks in the right front and center fittings and welded washers to them, he also replaced a few tubes in the floor at that time too.

My questions are, how to best drill the holes in the welded washers and make sure I'm as accurate as possible in hitting center and not inducing stress in the gear after it's bolted on and flying by having off center holes.

The first 2 photos show the right front gear fitting, front and back. As you can see, there's no way to be sure the washer is centered in the hole from the rear, so I don't think I can use that as a guide. Trying to drill from the front gives no guarantee that I can hit dead center either because of the rough weld surface, the same on the center fitting in the next set of photos.

My idea is to bolt up the oleo and axel strut and use those as a drill guides to have everything line as much as possible. Does that sound like a good plan? Do you guys have any other ideas that I could do without a full jig?

Oh yeah, all those other gear repairs were done years ago, way before I bought my Champ, I did not ground loop it.







The center fitting, front and back

[Richard Murray]

James,

This is hindsight, but didn't they bolt the gear and washers together and true everything before welding? Why was the center welded shut?
Your thought to use the gear as a guide at this point seems like the only method left to true things up.

Richard

[james gevay]

You're right, I didn't have the gear on the fuselage as it was welded up.
You can also see the ID of the washers have a smaller hole than the final hole size too.

[clipperfixer]

That weld is gonna be plenty hard. What I would do is grind the weld so you can get the gear leg back in. put the rear mount bolt in. Then make a bushing that extends from the good hole in the front through the front gear mount and push it up against the welded hole. The bushing would be the OD of the gear bolt and the ID would be a size to start drilling with. You could use like a 3/16" drill first. Once you have the hole piloted you can take the gear out and then ream it up to size. If you can't make a bushing you might use some raw bushing stock from wag. Drill with whatever the ID is. To step it up I would use at least a 4 fluted drill bit or reamers. If you are at a loss for finding drills or reamers to fit I may be able to help you depending on what size you need. If you just try to drill through everything with a bit the size of the bolt you might have a problem on your hands.
Ray

[colie85857]

read up on Aeronca service letter # 6, about repair of landing gear fittings.

[Richard Murray]

Here's a link to Service Letter #6
http://aeronca.celinaux.com/SL/SL-6.pdf

[MikeB]

Jim, I can't imagine why the holes were welded shut other than to fill the oversize holes but I've seen several repaired in accordance with SL6 including welding a piece of metal over the outboard side and a bushing to fill the inboard resized hole. Anyway, what's done is done so now you'll just have to deal with the problem as is. Using the gear as a guide to probably a good idea. Regarding the center section where the gear attaches to the fuselage. I've made a new piece out of metal (probably 1/8 or so) by tracing the old piece and welded it directly to the outside of the old damaged piece. Adds a little weight but it's much stronger.
Mike

[james gevay]

Maybe I should have been clearer in my description.

[b]None of the holes are oversize.
[/b]

Only the rear part of each fitting was welded recently and has the smaller hole on one side of the washer and the welded up hole on the other side.
The right front fitting fits a AN-6 bolt, and the center axle fitting fits a AN-5 bolt.
I do appreciate your comments and suggestions guys.