Brodhead Pietenpol Association

Per plans, I drilled 1/4" holes through the barrel hinges for the landing gear (split gear), then welded it all. Everything was fine. I then drilled those holes (on aircraft right) to 5/16", per plans, but the alignment was lost. I had to make six new barrels on that side and re-weld to the fittings.

I'm now looking at the other side and wondering how to enlarge the holes in those six barrels to 5/16" while maintaining alignment. I bought three intermediate drill bits thinking I could slowly accomplish the task, but the first step, a 7/64" bit, wants to dig in, so that's not going to work.

Wondering what others have done. Thanks!

John C

I can tell you what happens when they don't align closely enough and the next size overbore leaves play, because that's what my landing gear have. When I taxi over uneven terrain, the gear clunks. It's not big clunks and they aren't loud, but they are clunks. With the plane parked in the hangar, if I put my shoe on top of one of the tires and move it back and forth, I can see and hear the clunking from the play in the attachments.

You might investigate metric size bits to creep up on the 5/16" close fit. Maybe one of those will be a snugger fit than the 7/64"-?

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

If I remember correctly, the mating barrels for the landing gear pivot points on the gear that is now under Ken Bickers's Piet was a very nice tight fit. I thought that set of gear legs was quite well made.

-Oscar

I lost the alignment not just the entire side, but in each fitting area. I'll take your suggestion to look at metric. I'll report back.

Thanks!

John C

John,

Oscar is correct the gear lugs line up and fit nicely on mine. I didn't build it, so cannot offer any specific solutions.

One thought that I have is that the issue maybe less the bits and more about the technique. Here's what I've done in other application: put a bolt in from the oppositie side that is sized to the current holes. Then drill forward, with your bit pushing the bolt out as the bit goes in. Upsize the bolt to the new hole size and repeat. For the final hole size, I try to use a reamer to ensure a smooth surface the length of the hole.

As an FYI, my gear was built by Jack Kearbey from Collinsville, Oklahoma, for Arlene Walsh, who at the time was building an Aerial. Sometime after her death in a car accident, the gear was acquired by Oscar and later gifted to me after my original gear was scrubbed off in an off-field landing. It might be that Jack Kearbey is available to answer questions. He's a well-known builder of antique airplanes, most notably an SE5a. Somebody doubtless has his contact information.

Good luck, Ken

Thanks Ken. I now have seven drill bits (some on order) to take me up to the final 5/16" bit. Hopefully, these eight will get the job done. I'll keep a look-out for Jack and see what he has to say about it.

John

John,

That's terrific. You can actually use the bolt-push method by slipping the previous drill bit in backwards on the opposite side of the hole. The next size up will push that one out. You can then swap in the bit you just used to enlarge the hole by slipping it in backwards on the opposite side and pushing it slowly out with the bit that is the next size up. That "should" keep everything aligned as you step up the hole sizes.

Please let everyone know what works (or doesn't). One of the main virtues of this website is that it is a searchable record of building information, unlike the Facebook site, which is terrible as a resource for future builders.

Cheers, Ken

Thanks Ken. I'll post results after I drill the barrels.

John

Used a laser and bolts on the other side to guide me through. Didn't work. I'll have to cut the barrels off and I may be able to re-weld them into the correct orientation.

That's unfortunate. What doesn't work is useful information. Thanks for sharing. Please keep doing so.

Cheers, Ken