Confused by Idler

[Andy Walker]

Hey all...

I'm working on building my elevator idler, and the plans have me thoroughly confused. There are two sets of bushings (one bronze, one steel) and a AN3-7A bolt. What exactly is supposed to rotate? Just the idler itself, the bolt & idler, or the idler, bolt, and inner bushings??

The plans say "line ream pivot bushing to achieve a snug, but free to rotate fit with -23 pivot bushing and idler." This indicates to me that the idler and bolt are the only things free to rotate, and the inner and outer bushings are just press fit together, which I did easily with an arbor press. Am I correct here? Here's what I have:



The way mine is now, the idler will rotate on the bolt, held snug against the bushings on the side. The bolt may or may not rotate, but is pretty much free to do so...is that correct?

[sonex892]

I could be wrong but this is what I think. Idler is clamped solid on assembly with steel bushings and the bolt. The steel bushings then rotate in the bronze bushings. Which as you said are a press fit in the aluminium angle.

The moving sufaces on all these bronze bushings in the sonex should be steel on bronze. (Steel not including the bolt. The bolt should not be able to rotate freely)

[Andy Walker]

I could be wrong but this is what I think. Idler is clamped solid on assembly with steel bushings and the bolt. The steel bushings then rotate in the bronze bushings. Which as you said are a press fit in the aluminium angle.

The moving sufaces on all these bronze bushings in the sonex should be steel on bronze. (Steel not including the bolt. The bolt should not be able to rotate freely)

Re-reading with my wife helping me understand English, I think you are correct. The problem is that the plans use "pivot bushing" to refer to both the steel and bronze bushings, it would be nice if they'd use different terms. So I guess I need to ream out the bronze bushings so that the steel ones are free to rotate. BUT...how do I ensure that the bolt doesn't rotate? There's nothing to keep it from just spinning in the steel bushing. Do I just put enough clamp on it with the castel nut to prevent this?

[Mike53]

Andy I found this if it helps.http://youtu.be/kTYEcZHs45c and the forum talk here http://groups.yahoo.com/group/sonextalk/message/51483

[sonex892]

BUT...how do I ensure that the bolt doesn't rotate? There's nothing to keep it from just spinning in the steel bushing. Do I just put enough clamp on it with the castel nut to prevent this?

Yes thats it Andy tighten the bolt enough to clamp it. Even though most of the other bearings are a different configuration. Its basically the same for all the other bearings. Such as the other elevator bearings and aileron bellcranks. They just need to be clamped with the bolt

[sonex892]

BUT...how do I ensure that the bolt doesn't rotate? There's nothing to keep it from just spinning in the steel bushing. Do I just put enough clamp on it with the castel nut to prevent this?

Yes thats it Andy, tighten the bolt enough to clamp it. Even though most of the other bearings are a different configuration. Its basically the same for all the other bearings. Such as the other elevator bearings and aileron bellcranks. They just need to be clamped with the bolt

[Andy Walker]

BUT...how do I ensure that the bolt doesn't rotate? There's nothing to keep it from just spinning in the steel bushing. Do I just put enough clamp on it with the castel nut to prevent this?

Yes thats it Andy, tighten the bolt enough to clamp it. Even though most of the other bearings are a different configuration. Its basically the same for all the other bearings. Such as the other elevator bearings and aileron bellcranks. They just need to be clamped with the bolt

Great, thanks!

[Andy Walker]

Okay, so I got the idler together. The plans say to shim with paper until the idler is "snug but free to rotate." Using a 0.032" metal shim, idler rotates, but is more "stiff" than "snug." I don't think that I should shim much more than that. How freely should the idler arm move?