Gear leg length

[Bryan Cotton]

So my plans say 34" for length, but my parts are 1/8" longer than that. I am tempted to leave that 1/8" on and deprive myself of the joy of cutting the ti rod. Anybody else guilty?

[Gripdana]

Yes mine were long. The extra length simply runs out the top of the mount.

[Gripdana]

This is an old photo. The SB has been done on the bolts.

[Sonex1517]

I am with Dana - the extra is sticking out the top a little bit.


Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved

[Bryan Cotton]

Well, I guess I'll have to slide that hole down a bit then.

[Sonex1517]

I am also going to install AN4H-30 bolts at the recommendation of someone who suffered through a failure.


Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved

[GordonTurner]

What is the AN4H-30 bolt and why is it needed? Is it hard to find or install?

[Bryan Cotton]

Typed in a long reply and my darn iphone lost it. Trying again on from Ubuntu.

Gordon,
AN4H is a 1/4" AN bolt with a drilled head for safety wire. I assume it is wired so the bolt doesn't fall out if it breaks, but I don't know.

No problems drilling the Ti. I drilled up in 3 steps, #30, 3/16", and 1/4". Slow going with the #30, lots of clearing of the chips and time to cool down. Bought fancy "cold fire" bits for the 3/16" and 1/4". The 3/16" worked ok, the 1/4" bit died immediately. Took out a plane jane black oxide 1/4" bit from sears and it drilled through no problem. I used the idea attributed to Bob Mika, didn't drill through until the very end so the hole would hold oil. That was genius. I used MM air tool oil rather than WD40. Started with WD40 but it was working poorly for me.

So my gear legs fit tight in the sockets, which is good. Hard to align the 1/4" hole in the motor mount with the 1/4" hole in the gear leg due to friction. I think I will taper a 1/4" steel rod and tap it in. Anybody want to share their technique? I plan to align the holes then finish drilling through the back of the motor mount.

Here is my drill press setup:


Here is the first leg stuck in:

[ScottM-Sonex1629]

Bryan,

I had a different gear arrangement, but did the drilling in stages similar to how you're doing it. Every stage I updrilled I would start with the gear In the weldments (or motor mount for your case), then remove the TI leg and finish in the drill press, then transfer back to the mount so I could finish the through drilling of the mount so the hole was straight. Not sure if that makes sense or helps you out...but it mostly worked for me.

[Sonex1517]

What is the AN4H-30 bolt and why is it needed? Is it hard to find or install?

Per the guy that suggested it, as Bryan explained these bolts (available through Aircraft Spruce for about $5 each) have a drilled head and drilled thread.

I believe the suggestion stemmed from broken bolts resulting in a gear failure with damage to the aircraft. The idea being that if the safety wire is done correctly, the bolts breaking would not result in the gear departing or collapsing.

I am paraphrasing. I have not had the issue personally.

Maybe someone with more knowledge than I can interject.


Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved